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Equivalent focal lengths and crop factors...

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Anonymous
December 22, 2004 9:40:14 AM

Archived from groups: rec.photo.digital.slr-systems (More info?)

Haven't read here for a while. Wondered when all this would surface
here. Well, it has and it won't go away, so maybe some clarification is
in order.

This whole subject is what happens when the tech geeks and the arty
types fail to communicate, things get lost in the cracks, important
things. We have focal lengths, equivalent focal lengths, angles of
view, image area, depth of field, frame composition, perspective...
real hodge podge!

Two things that weren't considered, and are important, are:

1) The interface between photographer and camera, the view finder.

The one thing that does not ever change is the natural field of vision
of an individual, the inherent angle of view. That's the bench mark.
Now, an individual looks throught the viewfinder of a camera. If it's
an SLR, the viewfinder presents a perceived angle of view that does not
change. It does not allow the viewer to perceive the change in the
lens' angle of view.

Look through a rangefinder with interchangeable lenses. Different
marked off fields of view, so the viewer can perceive the changed angle
of view. Since the viewfinder is not part of the lens' optical train,
the perceived angle of view *of the viewfinder* does not change, and the
sense of the differences between the "perspectives" of different focal
length lenses is not apparent.

What happens with the SLR is that the eye is fooled into thinking that
what he/she sees has changed, when it has in fact not changed at all.
How that happens is obvious: A "standard" lens is one that will present
to the viewfinder what the eye would see if the viewfinder were a simple
window, unaltered by an optical train. One can often shoot with both
eyes open using a standard lens, without suffering the effects of
difference perceived by each eye.

Can't do that with a telephoto or wide angle. Well, at least I can't...

So what is going on here is that the camera user comes to identify the
perceived effect of different focal lengths, and comes to associate
particular differences with particular focal length lenses. And this is
why the persistent popularity of the "equivalent focal length".

Are the tech geeks right? Yep, they are. Is that important? Yep, it
is. Why? Because some things don't change, and one of them is DOF.
Another is relative distortion of the scene image. Both of these are
very important, of course.

Which leads to the second thing.

2) Perspective.

It turns out that there are two different definitions in common usage.
Now never mind the dictionaries, we know this without consulting them.
The first and literal definition is "what you see from where you are".
Here, we're talking about what you can and cannot see from a point of
view, which changes when the point of view is changed. You change your
viewing position, and some things that were not visible become so, and
some things that were visible, now are not.

That's not the same as the second definition, which has to do with the
relative size of viewed objects. The problem here is that this second
definition can easily be assumed to be a subset of the first: Things
get larger as one gets closer; given the natural angle of view, moving
closer makes an object take up more room in the field of vision.

However, the relative size of objects in the scene can be made
independent of the point of view created perspective. That is easily
accomplished with optics (and recorded in camera) by distorting the
scene optically. Artists do this all the time to achieve the effects
they want. They call it a change in perspective, and their use of the
term is what has established the second definition. Artists use
cameras, and so photography uses both definitions.

What's the problem? Well, there's a "gotcha!!" lurking here. And that
is that a photographer expects the camera to record reality as it is,
because that's what cameras are supposed to do. Right?

Well, that's as may be, but the reality is that no, they do not. What
they do is record an optically produced image, whatever that may be, and
the unwary can really get confused when optical distortion is not
acknowledged.

Here's the reality check: If things change in relative size, expect
different things to be visible. If different things are not visible,
you're looking at an optically produced distortion. And that's how you
tell which definition is being used.

The arty types don't care about all this "semantic detail". Perspective
change via distortion and perspective change via change in position are
deemed equivalent for their purposes, or so it seems. Not being an arty
type I wouldn't know for sure.

The tech geeks insist that they are entirely different things and should
never be confused. Perspective change is never produced by a change in
focal length, so they say, and according to the first definition, they're
right. And for them, apparently, that's all that matters. Not being a
tech geek, I wouldn't know for sure.

The truth is that both are missing an important aspect of this business,
and that is the effect these changes have on the viewer. Trouble is,
both types are also viewers, and because of this lack of complete
understanding, cannot come to an agreement about what's what.

There are some truths in some of the statements made, of course.

You cannot change perspective of the first definition by changing focal
lengths. But it's equally true that you certainly can change
perspective by the second definition by changing focal lengths. What
makes both true is that one makes the change by distortion and the other
does not.

As a camera user of some experience, you can equate the angle of view
provided by a focal length in one format with the perceived angle of
view in another. But the lenses themselves do not change focal length,
nor do they change angle of view. Enter the crop factor.

Incidentally, an optical train is an optical train whether displaying a
recorded image, or recording a displayed image. Optical crop is optical
crop. No, the two trains are not designed alike, but that's irrelevant.
For what its worth, that is...

Maybe if you guys would think all this through, you would realize that
reality does not change, and that differences in opinion are the result
of different perceptions. You want to be completely right? Better
think these things through a bit better. Otherwise, all you guys have
stuff to learn, and are better off listening to each other and trying to
figure out what you've missed.

Myself included, of course. I walk the walk I talk: tell me where I
screwed up here, or what I missed and I'll willingly stand instructed.

Will D.
December 22, 2004 12:52:45 PM

Archived from groups: rec.photo.digital.slr-systems (More info?)

"A "standard" lens is one that will present
to the viewfinder what the eye would see if the viewfinder were a simple
window, unaltered by an optical train."

I don't believe this was true on a 35mm film as the standard is 50mm when
approx a 70mm will give 1:1, but with a 1.6 crop with most digitals it may
now be right !

"Will D." <willd@no.spam> wrote in message
news:10si5mee4a5k3aa@corp.supernews.com...
> Haven't read here for a while. Wondered when all this would surface
> here. Well, it has and it won't go away, so maybe some clarification is
> in order.
>
> This whole subject is what happens when the tech geeks and the arty
> types fail to communicate, things get lost in the cracks, important
> things. We have focal lengths, equivalent focal lengths, angles of
> view, image area, depth of field, frame composition, perspective...
> real hodge podge!
>
> Two things that weren't considered, and are important, are:
>
> 1) The interface between photographer and camera, the view finder.
>
> The one thing that does not ever change is the natural field of vision
> of an individual, the inherent angle of view. That's the bench mark.
> Now, an individual looks throught the viewfinder of a camera. If it's
> an SLR, the viewfinder presents a perceived angle of view that does not
> change. It does not allow the viewer to perceive the change in the
> lens' angle of view.
>
> Look through a rangefinder with interchangeable lenses. Different
> marked off fields of view, so the viewer can perceive the changed angle
> of view. Since the viewfinder is not part of the lens' optical train,
> the perceived angle of view *of the viewfinder* does not change, and the
> sense of the differences between the "perspectives" of different focal
> length lenses is not apparent.
>
> What happens with the SLR is that the eye is fooled into thinking that
> what he/she sees has changed, when it has in fact not changed at all.
> How that happens is obvious: A "standard" lens is one that will present
> to the viewfinder what the eye would see if the viewfinder were a simple
> window, unaltered by an optical train. One can often shoot with both
> eyes open using a standard lens, without suffering the effects of
> difference perceived by each eye.
>
> Can't do that with a telephoto or wide angle. Well, at least I can't...
>
> So what is going on here is that the camera user comes to identify the
> perceived effect of different focal lengths, and comes to associate
> particular differences with particular focal length lenses. And this is
> why the persistent popularity of the "equivalent focal length".
>
> Are the tech geeks right? Yep, they are. Is that important? Yep, it
> is. Why? Because some things don't change, and one of them is DOF.
> Another is relative distortion of the scene image. Both of these are
> very important, of course.
>
> Which leads to the second thing.
>
> 2) Perspective.
>
> It turns out that there are two different definitions in common usage.
> Now never mind the dictionaries, we know this without consulting them.
> The first and literal definition is "what you see from where you are".
> Here, we're talking about what you can and cannot see from a point of
> view, which changes when the point of view is changed. You change your
> viewing position, and some things that were not visible become so, and
> some things that were visible, now are not.
>
> That's not the same as the second definition, which has to do with the
> relative size of viewed objects. The problem here is that this second
> definition can easily be assumed to be a subset of the first: Things
> get larger as one gets closer; given the natural angle of view, moving
> closer makes an object take up more room in the field of vision.
>
> However, the relative size of objects in the scene can be made
> independent of the point of view created perspective. That is easily
> accomplished with optics (and recorded in camera) by distorting the
> scene optically. Artists do this all the time to achieve the effects
> they want. They call it a change in perspective, and their use of the
> term is what has established the second definition. Artists use
> cameras, and so photography uses both definitions.
>
> What's the problem? Well, there's a "gotcha!!" lurking here. And that
> is that a photographer expects the camera to record reality as it is,
> because that's what cameras are supposed to do. Right?
>
> Well, that's as may be, but the reality is that no, they do not. What
> they do is record an optically produced image, whatever that may be, and
> the unwary can really get confused when optical distortion is not
> acknowledged.
>
> Here's the reality check: If things change in relative size, expect
> different things to be visible. If different things are not visible,
> you're looking at an optically produced distortion. And that's how you
> tell which definition is being used.
>
> The arty types don't care about all this "semantic detail". Perspective
> change via distortion and perspective change via change in position are
> deemed equivalent for their purposes, or so it seems. Not being an arty
> type I wouldn't know for sure.
>
> The tech geeks insist that they are entirely different things and should
> never be confused. Perspective change is never produced by a change in
> focal length, so they say, and according to the first definition, they're
> right. And for them, apparently, that's all that matters. Not being a
> tech geek, I wouldn't know for sure.
>
> The truth is that both are missing an important aspect of this business,
> and that is the effect these changes have on the viewer. Trouble is,
> both types are also viewers, and because of this lack of complete
> understanding, cannot come to an agreement about what's what.
>
> There are some truths in some of the statements made, of course.
>
> You cannot change perspective of the first definition by changing focal
> lengths. But it's equally true that you certainly can change
> perspective by the second definition by changing focal lengths. What
> makes both true is that one makes the change by distortion and the other
> does not.
>
> As a camera user of some experience, you can equate the angle of view
> provided by a focal length in one format with the perceived angle of
> view in another. But the lenses themselves do not change focal length,
> nor do they change angle of view. Enter the crop factor.
>
> Incidentally, an optical train is an optical train whether displaying a
> recorded image, or recording a displayed image. Optical crop is optical
> crop. No, the two trains are not designed alike, but that's irrelevant.
> For what its worth, that is...
>
> Maybe if you guys would think all this through, you would realize that
> reality does not change, and that differences in opinion are the result
> of different perceptions. You want to be completely right? Better
> think these things through a bit better. Otherwise, all you guys have
> stuff to learn, and are better off listening to each other and trying to
> figure out what you've missed.
>
> Myself included, of course. I walk the walk I talk: tell me where I
> screwed up here, or what I missed and I'll willingly stand instructed.
>
> Will D.
>
>
>
Anonymous
December 22, 2004 3:54:13 PM

Archived from groups: rec.photo.digital.slr-systems (More info?)

In article <cqbg5o$3o8$1@newsg4.svr.pol.co.uk>, dylan <spam@none.com> wrote:
>"A "standard" lens is one that will present
>to the viewfinder what the eye would see if the viewfinder were a simple
>window, unaltered by an optical train."
>
>I don't believe this was true on a 35mm film as the standard is 50mm when
>approx a 70mm will give 1:1, but with a 1.6 crop with most digitals it may
>now be right !

I guess you grew up with the modern auto-everything cameras, and their tiny
little viewfinders. Try looking through the viewfinder of an older camera
some time; something like a Nikon F2, or even just a Pentax Spotmatic.

Unfortunately when more and more camera automation came along, the makers
had a problem. They were stuck with three choices: to not present details
of what the camera was doing in the viewfinder (unacceptable in those days;
photographers might accept some level of automation, but they knew enough
not to trust the camera without verification); to present the information
alongside the traditional viewfinder (expensive, and difficult to use for
people wearing eyeglasses), or to reduce the size of the viewfinder image
to free up some space for all the additional display.

The modern digitals have, quite often, chosen to shrink the usage even
more (presumably because they share viewfinder optics with a film sibling);
the D70 still only has a magnification of 0.8 with a 50mm lens. Even the
D2X only gets a little better, at 0.86X. Canon are slightly better; the
0.70 of the 1DsII is somewhat understandable because of the larger sensor,
and the 300D matches the D70 at 0.8x. The 10D and 20D are both close to
0.9x, which is better than the far more expensive D2!
But the best viewfinder I've seen in a DSLR is in the Pentax *ist-D/DS.
These both have viewfinder magnifications of 0.95. Considering the fact
that the *ist-DS is in the same price bracket as the D70 and 300D, it's
quite impressive to see a viewfinder that large in a budget(sic) DSLR.

Disclaimer: I own a *ist-D. But I've used several of the alternatives
(including a D1, a 10D, and a D100), so I speak from personal experience.
Related resources
Anonymous
December 22, 2004 4:44:54 PM

Archived from groups: rec.photo.digital.slr-systems (More info?)

(repost - server prob.)

dylan wrote:

> "A "standard" lens is one that will present
> to the viewfinder what the eye would see if the viewfinder were a simple
> window, unaltered by an optical train."
>
> I don't believe this was true on a 35mm film as the standard is 50mm when
> approx a 70mm will give 1:1, but with a 1.6 crop with most digitals it may
> now be right !

Think you could not top post and snip away what is not needed?

The "normal" view with a cropped sensor (1.5) would be about 30 to 35mm, not 70mm.

Cheers,
Alan.

--
-- r.p.e.35mm user resource: http://www.aliasimages.com/rpe35mmur.htm
-- r.p.d.slr-systems: http://www.aliasimages.com/rpdslrsysur.htm
-- [SI] gallery & rulz: http://www.pbase.com/shootin
-- e-meil: there's no such thing as a FreeLunch.
Anonymous
December 22, 2004 6:59:50 PM

Archived from groups: rec.photo.digital.slr-systems (More info?)

Will D. <willd@no.spam> wrote:

> You cannot change perspective of the first definition by changing focal
> lengths. But it's equally true that you certainly can change
> perspective by the second definition by changing focal lengths. What
> makes both true is that one makes the change by distortion and the other
> does not.

The relative size of objects with distance does not change with focal length.
You can easily prove this for yourself with the usual experiments.

Take two pictures from exactly the same point, one with a telephoto and one
with a wide angle, not moving the camera in between. Crop the wide angle
shot so that its framing matches the telephoto shot, and you will see that
they are identical. There is no distortion, and there is no perspective
change by either of your definitions.

--
Jeremy | jeremy@exit109.com
Anonymous
December 22, 2004 7:17:38 PM

Archived from groups: rec.photo.digital.slr-systems (More info?)

"Will D." <willd@no.spam> writes:

> You cannot change perspective of the first definition by changing focal
> lengths. But it's equally true that you certainly can change
> perspective by the second definition by changing focal lengths. What
> makes both true is that one makes the change by distortion and the other
> does not.

The change you are making in 'distortion' are not changing the
perspective. Were this the case, then the objects present in both
frames would have different 'perspectives' (which they do not). The
'perspective' here is created by including other objects around the
edges which were not included in the first frame (or removing them).

B>
Anonymous
December 22, 2004 9:19:42 PM

Archived from groups: rec.photo.digital.slr-systems (More info?)

"dylan" <spam@none.com> writes:

> "A "standard" lens is one that will present
> to the viewfinder what the eye would see if the viewfinder were a simple
> window, unaltered by an optical train."
>
> I don't believe this was true on a 35mm film as the standard is 50mm when
> approx a 70mm will give 1:1, but with a 1.6 crop with most digitals it may
> now be right !

70mm will give 1:1? How can you possibly make this statement given the
huge range of viewfinder magnifications available?

B>
December 22, 2004 9:19:43 PM

Archived from groups: rec.photo.digital.slr-systems (More info?)

Let me try to explain.

If I look through my EOS 3 using a 24-85mm lens and compare the view through
the viewfinder with the view with my eyes I get the same size image direct
or through viewfinder when the lens is 70mm. If I try my EOS-10D the setting
is between 50 and 55mm.

Looking at the new Nikon F6, as an example, they quote viewfinder
magnification as .74 with 50mm and the EOS 1Ds Mk2 is .70 at 50mm.

The diagonal coverage of a 50mm is 40deg and a 70mm is 29deg giving a
maginification of 1.38.

1.38 x 0.7 = .96 and 1.38 x .74 = 1.02

both near enough to 1 for me.

Obviously as you say if there are other magnifications then this doesn't
work, ie Minolta 7 is 0.8 at 50mm, but I've always 70mm to be correct for my
cameras.

Certainly not the standard 50mm !!

Cheers



"Bruce Murphy" <pack-news@rattus.net> wrote in message
news:m2acs6ws75.fsf@greybat.rattus.net...
> "dylan" <spam@none.com> writes:
>
>> "A "standard" lens is one that will present
>> to the viewfinder what the eye would see if the viewfinder were a simple
>> window, unaltered by an optical train."
>>
>> I don't believe this was true on a 35mm film as the standard is 50mm when
>> approx a 70mm will give 1:1, but with a 1.6 crop with most digitals it
>> may
>> now be right !
>
> 70mm will give 1:1? How can you possibly make this statement given the
> huge range of viewfinder magnifications available?
>
> B>
Anonymous
December 22, 2004 9:42:21 PM

Archived from groups: rec.photo.digital.slr-systems (More info?)

On 2004-12-22, Jeremy Nixon <jeremy@exit109.com> wrote:
> Will D. <willd@no.spam> wrote:
>
>> You cannot change perspective of the first definition by changing focal
>> lengths. But it's equally true that you certainly can change
>> perspective by the second definition by changing focal lengths. What
>> makes both true is that one makes the change by distortion and the other
>> does not.
>
> The relative size of objects with distance does not change with focal length.
> You can easily prove this for yourself with the usual experiments.
>
> Take two pictures from exactly the same point, one with a telephoto and one
> with a wide angle, not moving the camera in between. Crop the wide angle
> shot so that its framing matches the telephoto shot, and you will see that
> they are identical. There is no distortion, and there is no perspective
> change by either of your definitions.

This is true, but you miss the entire point:

It is the perceived angle of view a) through the viewfinder, and b) when
viewing a print in the normal manner, that creates this effect.

The viewfinder enforces a single angle of view, and so does the standard
print viewing practice. The latter would have you hold the print at
approximately the distance equal to the diagonal of the print itself.

If you want to complete the experiment you cite properly, you should
view the prints at the appropriate distances. For the wide angle shot,
put your nose on the surface of the print, or thereabouts. For the
telephoto shot, stand back across the room. In both cases, the
distortion effect is cancelled. Of course, that might not serve the
intent of the photographer...

But you cannot do this with your viewfinder, and so cannot cancel the
perceived distortion effect at that point in the process.

Again, think this through to the end, and you'll likely answer your own
questions.

Will D.
December 22, 2004 9:52:40 PM

Archived from groups: rec.photo.digital.slr-systems (More info?)

I never said 'normal' (whatever that is) was 70mm with a 1.5 crop. All I
know is if I look through my EOS-1D with approx 50mm lens the image in the
viewfinder is the same size to my eye as looking without the camera, 1.5 x
50mm = 75mm.

Cheers

"Alan Browne" <alan.browne@freelunchVideotron.ca> wrote in message
news:cqcfam$a6j$1@inews.gazeta.pl...
>
> The "normal" view with a cropped sensor (1.5) would be about 30 to 35mm,
> not 70mm.
>
..
December 22, 2004 9:54:05 PM

Archived from groups: rec.photo.digital.slr-systems (More info?)

try EOS-10D not 1D, my typo

"dylan" <spam@none.com> wrote in message
news:cqcfq4$cti$1@newsg3.svr.pol.co.uk...
>I never said 'normal' (whatever that is) was 70mm with a 1.5 crop. All I
>know is if I look through my EOS-1D with approx 50mm lens the image in the
>viewfinder is the same size to my eye as looking without the camera, 1.5 x
>50mm = 75mm.
>
> Cheers
Anonymous
December 22, 2004 10:20:44 PM

Archived from groups: rec.photo.digital.slr-systems (More info?)

"dylan" <spam@none.com> writes:

> Let me try to explain.
>
> If I look through my EOS 3 using a 24-85mm lens and compare the view through
> the viewfinder with the view with my eyes I get the same size image direct
> or through viewfinder when the lens is 70mm. If I try my EOS-10D the setting
> is between 50 and 55mm.
>
> Looking at the new Nikon F6, as an example, they quote viewfinder
> magnification as .74 with 50mm and the EOS 1Ds Mk2 is .70 at 50mm.

Not a particularly wide selection. The high-end bodies in both ranges
tend to have fairly similar eyepiece magnifications.

> The diagonal coverage of a 50mm is 40deg and a 70mm is 29deg giving a
> maginification of 1.38.
>
> 1.38 x 0.7 = .96 and 1.38 x .74 = 1.02
>
> both near enough to 1 for me.
>
> Obviously as you say if there are other magnifications then this doesn't
> work, ie Minolta 7 is 0.8 at 50mm, but I've always 70mm to be correct for my
> cameras.

Things vary a bit more with some of the manual focus bodies.

> Certainly not the standard 50mm !!

The 'standard' lens is defined in terms of closeness to the diagonal
of the format in question. With such a lens (actually around 45mm on
35mm format) coupled with that format, you'll end up with a print
whose perspective looks natural at a normal viewing distance. In
contrast, shorter lenses will produce prints whose perspective looks
odd unless you're closer, and longer ones odd images unless you are
further away.

B>
Anonymous
December 23, 2004 10:30:46 AM

Archived from groups: rec.photo.digital.slr-systems (More info?)

Will D. <willd@no.spam> wrote:

> If you want to complete the experiment you cite properly, you should
> view the prints at the appropriate distances. For the wide angle shot,
> put your nose on the surface of the print, or thereabouts. For the
> telephoto shot, stand back across the room. In both cases, the
> distortion effect is cancelled. Of course, that might not serve the
> intent of the photographer...

Except that the wide-angle shot, once cropped, *becomes* a telephoto
shot. Cropping it is, for the purpose of the experiment, the same thing
as using a longer focal length -- this is the conclusion of the
experiment, not the premise, but in the end, zooming in is just a way
to optically crop the image.

The relative sizes of objects according to distance is a function of
the distances involved -- the lens can't change them, unless it's
distorting them due to optical defects, which doesn't really count.

When you look through a long telephoto lens, it may look like the
distances are compressed, but that is an illusion coming from the fact
that you are seeing the scene in a way your unaided eye cannot. The
perspective is actually identical to what you see with any focal length.

--
Jeremy | jeremy@exit109.com
Anonymous
December 23, 2004 10:45:35 PM

Archived from groups: rec.photo.digital.slr-systems (More info?)

On 2004-12-23, Jeremy Nixon <jeremy@exit109.com> wrote:
> Will D. <willd@no.spam> wrote:
>
>> If you want to complete the experiment you cite properly, you should
>> view the prints at the appropriate distances. For the wide angle shot,
>> put your nose on the surface of the print, or thereabouts. For the
>> telephoto shot, stand back across the room. In both cases, the
>> distortion effect is cancelled. Of course, that might not serve the
>> intent of the photographer...
>
> Except that the wide-angle shot, once cropped, *becomes* a telephoto
> shot. Cropping it is, for the purpose of the experiment, the same thing
> as using a longer focal length -- this is the conclusion of the
> experiment, not the premise, but in the end, zooming in is just a way
> to optically crop the image.

Well, if the point you are making is that photographic optical trains do
not introduce gratuitous distortion, you are correct, AFAIK. But that
does not address the issue I raised.

> The relative sizes of objects according to distance is a function of
> the distances involved -- the lens can't change them, unless it's
> distorting them due to optical defects, which doesn't really count.

Yes, we can assume no gratuitous distortions, I think.

> When you look through a long telephoto lens, it may look like the
> distances are compressed, but that is an illusion coming from the fact
> that you are seeing the scene in a way your unaided eye cannot. The
> perspective is actually identical to what you see with any focal length.

An illusion is an apparency that is the function of the interpretive
mind, which is classically dispelled by blinking one's eyes and taking
another look. Big noses and tiny ears in portraits taken with wide
angle lenses cannot be dispelled by blinking one's eyes. Compared to
what one sees with unaided vision, they constitute distortions.

I defined the second usage of the term "perspective" as caused by
distortion, because we are accustomed to gauging our position in our
environment, in part, by the relative size of the objects around us.
You can make the case that this second definition is an illusory
corollary of the first, but the fact is that artists have long used this
second definition and thus it is customary usage in photography.

Will D.
Anonymous
December 23, 2004 11:01:55 PM

Archived from groups: rec.photo.digital.slr-systems (More info?)

Will D. <willd@no.spam> wrote:

> An illusion is an apparency that is the function of the interpretive
> mind, which is classically dispelled by blinking one's eyes and taking
> another look. Big noses and tiny ears in portraits taken with wide
> angle lenses cannot be dispelled by blinking one's eyes. Compared to
> what one sees with unaided vision, they constitute distortions.

But they are not a product of focal length, nor is the amount of such
visual distortion a function of focal length. It is not the wide-angle
lens that causes this.

--
Jeremy | jeremy@exit109.com
Anonymous
December 24, 2004 10:40:18 PM

Archived from groups: rec.photo.digital.slr-systems (More info?)

On 2004-12-23, Jeremy Nixon <jeremy@exit109.com> wrote:
> Will D. <willd@no.spam> wrote:
>
>> An illusion is an apparency that is the function of the interpretive
>> mind, which is classically dispelled by blinking one's eyes and taking
>> another look. Big noses and tiny ears in portraits taken with wide
>> angle lenses cannot be dispelled by blinking one's eyes. Compared to
>> what one sees with unaided vision, they constitute distortions.
>
> But they are not a product of focal length, nor is the amount of such
> visual distortion a function of focal length. It is not the wide-angle
> lens that causes this.

Would you please explain this phenomena, then? Perhaps we all might
learn something here.

Will D.
Anonymous
December 24, 2004 10:40:19 PM

Archived from groups: rec.photo.digital.slr-systems (More info?)

Will D. wrote:
> On 2004-12-23, Jeremy Nixon <jeremy@exit109.com> wrote:
>> Will D. <willd@no.spam> wrote:
>>
>>> An illusion is an apparency that is the function of the interpretive
>>> mind, which is classically dispelled by blinking one's eyes and
>>> taking another look. Big noses and tiny ears in portraits taken
>>> with wide angle lenses cannot be dispelled by blinking one's eyes.
>>> Compared to what one sees with unaided vision, they constitute
>>> distortions.
>>
>> But they are not a product of focal length, nor is the amount of such
>> visual distortion a function of focal length. It is not the
>> wide-angle lens that causes this.
>
> Would you please explain this phenomena, then? Perhaps we all might
> learn something here.
>
> Will D.

Seems to me it has been esplained, discussed, and demonstrated to within
an inch of its (apparently eternal) life.

And without malice or meanness, just so at least one of us learns
something, it's "this phenomenon", "these phenomena".

Merry Christmas.


--
Frank ess
Anonymous
December 24, 2004 11:23:23 PM

Archived from groups: rec.photo.digital.slr-systems (More info?)

Will D. <willd@no.spam> wrote:

[so-called wide-angle distortion]
>> But they are not a product of focal length, nor is the amount of such
>> visual distortion a function of focal length. It is not the wide-angle
>> lens that causes this.
>
> Would you please explain this phenomena, then? Perhaps we all might
> learn something here.

I'm not sure how many different ways it can be explained before a few
people stop refusing to believe it.

It is a product of the camera position relative to the subject.

Some people *think* is has to do with the lens focal length because,
when using a wide angle lens, you get closer to the subject in order to
get the framing you want. But it is getting closer that does it. If
it had to do with focal length, you would get big noses and all that
stuff shooting a full-length picture of someone from 15 feet away with
a point and shoot digicam, since the lens would be less than 10mm.
But you don't, because it doesn't.

--
Jeremy | jeremy@exit109.com
Anonymous
December 25, 2004 10:19:09 AM

Archived from groups: rec.photo.digital.slr-systems (More info?)

"Frank ess" <frank@fshe2fs.com> wrote in message
news:a4GdnVFALqAd6FHcRVn-tA@giganews.com...
<snip>
> Seems to me it has been esplained, discussed, and demonstrated to within
> an inch of its (apparently eternal) life.
> And without malice or meanness, just so at least one of us learns
> something, it's "this phenomenon", "these phenomena".
>
> Merry Christmas.
> --
> Frank ess
-----------
Also, the word is spelled "explained" not "esplained". We all make errors
from time to time, don't we?
Merry Christmas to you and your family.
Don F
Anonymous
December 25, 2004 12:37:53 PM

Archived from groups: rec.photo.digital.slr-systems (More info?)

Don F wrote:
> "Frank ess" <frank@fshe2fs.com> wrote in message
> news:a4GdnVFALqAd6FHcRVn-tA@giganews.com...
> <snip>
>> Seems to me it has been esplained, discussed, and demonstrated to
>> within an inch of its (apparently eternal) life.
>> And without malice or meanness, just so at least one of us learns
>> something, it's "this phenomenon", "these phenomena".
>>
>> Merry Christmas.
>> --
>> Frank ess
> -----------
> Also, the word is spelled "explained" not "esplained". We all make
> errors from time to time, don't we?
> Merry Christmas to you and your family.
> Don F

Well, YOU can esplain that to Ricky and Lucy. Dipsh*t picayune spelling
cop. How do you feel now?

Merry Christms to you. (Big smiley face)

--
--
Frank ess
Anonymous
December 26, 2004 2:14:40 AM

Archived from groups: rec.photo.digital.slr-systems (More info?)

On 2004-12-24, Jeremy Nixon <jeremy@exit109.com> wrote:
> Will D. <willd@no.spam> wrote:
>
> [so-called wide-angle distortion]
>>> But they are not a product of focal length, nor is the amount of such
>>> visual distortion a function of focal length. It is not the wide-angle
>>> lens that causes this.
>>
>> Would you please explain this phenomena, then? Perhaps we all might
>> learn something here.
>
> I'm not sure how many different ways it can be explained before a few
> people stop refusing to believe it.
>
> It is a product of the camera position relative to the subject.
>
> Some people *think* is has to do with the lens focal length because,
> when using a wide angle lens, you get closer to the subject in order to
> get the framing you want. But it is getting closer that does it. If
> it had to do with focal length, you would get big noses and all that
> stuff shooting a full-length picture of someone from 15 feet away with
> a point and shoot digicam, since the lens would be less than 10mm.
> But you don't, because it doesn't.

What we have here is a failure to communicate, I must suppose. As I
originated the issue, I'll take responsibility for that failure, though
for the life of me I cannot see what it is you do not understand about
what I said.

Everything you have said is true, and I have agreed with you. If that
were all that were involved, this entire discussion would not be an
issue at all. Yet this issue continues to arise, over and over again.

There is more to the matter than just lens focal length. Because you
cannot grasp this, you cannot resolve the matter fully. You think you
have a pat answer that has been established long since, and you are
correct as far as you go. Problem is, you don't include the viewer in
the system you're analyzing.

In any case, I've done due diligence here.

Will D.
Anonymous
December 26, 2004 10:19:22 PM

Archived from groups: rec.photo.digital.slr-systems (More info?)

"Frank ess" <frank@fshe2fs.com> wrote in message
news:tNWdnVzHbN3nOFDcRVn-ig@giganews.com...

<snip>
> Well, YOU can esplain that to Ricky and Lucy. Dipsh*t picayune spelling
> cop. How do you feel now?
>
> Merry Christms to you. (Big smiley face)
>
> --
> --
> Frank ess
-----------------
Sad!
I feel fine, BTW. Thanks for asking.
Don F
Anonymous
January 2, 2005 7:34:31 PM

Archived from groups: rec.photo.digital.slr-systems (More info?)

"Will D." wrote:
>
><snip>
> An illusion is an apparency that is the function of the interpretive
> mind, which is classically dispelled by blinking one's eyes and taking
> another look. Big noses and tiny ears in portraits taken with wide
> angle lenses cannot be dispelled by blinking one's eyes. Compared to
> what one sees with unaided vision, they constitute distortions.
>
This effect - small ears and big noses - is because the viewing distance
of the photo is wrong. The 'correct' viewing distance of any image is
equal to the focal length of the taking lens times the subsequent
magnification applied to the image. At this distance - and only this
distance - the relative sizes of objects in the photograph will
correspond with what was seen by the lens when taking the shot. If you
view the image from too close, the perspective appears flattened, and
from too far away the perspective appears exaggerated. This is the
source of your ears/nose problem. Example: a portrait taken with a 24mm
lens on 35mm film, and enlarged to 10x8 will require a viewing distance
of 24mm x 8 (the degree of enlargement). This comes out to about 7.5
inches, much closer than one usually views a 10x8 print. However, if
you do view the image at that distance, the perspective will look right.
One definition of a 'normal' lens is when images from that lens, viewed
at the usual distance for the size of print, appears to have normal
perspective.

> I defined the second usage of the term "perspective" as caused by
> distortion, because we are accustomed to gauging our position in our
> environment, in part, by the relative size of the objects around us.
> You can make the case that this second definition is an illusory
> corollary of the first, but the fact is that artists have long used this
> second definition and thus it is customary usage in photography.

This follows from my above comments

Colin
Anonymous
January 2, 2005 7:34:32 PM

Archived from groups: rec.photo.digital.slr-systems (More info?)

On 2005-01-02, Colin D <ColinD@killspam.127.0.0.1> wrote:
>
>
> "Will D." wrote:
>>
>><snip>
>> An illusion is an apparency that is the function of the interpretive
>> mind, which is classically dispelled by blinking one's eyes and taking
>> another look. Big noses and tiny ears in portraits taken with wide
>> angle lenses cannot be dispelled by blinking one's eyes. Compared to
>> what one sees with unaided vision, they constitute distortions.
>>
> This effect - small ears and big noses - is because the viewing distance
> of the photo is wrong. The 'correct' viewing distance of any image is
> equal to the focal length of the taking lens times the subsequent
> magnification applied to the image. At this distance - and only this
> distance - the relative sizes of objects in the photograph will
> correspond with what was seen by the lens when taking the shot. If you
> view the image from too close, the perspective appears flattened, and
> from too far away the perspective appears exaggerated. This is the
> source of your ears/nose problem. Example: a portrait taken with a 24mm
> lens on 35mm film, and enlarged to 10x8 will require a viewing distance
> of 24mm x 8 (the degree of enlargement). This comes out to about 7.5
> inches, much closer than one usually views a 10x8 print. However, if
> you do view the image at that distance, the perspective will look right.
> One definition of a 'normal' lens is when images from that lens, viewed
> at the usual distance for the size of print, appears to have normal
> perspective.
>
>> I defined the second usage of the term "perspective" as caused by
>> distortion, because we are accustomed to gauging our position in our
>> environment, in part, by the relative size of the objects around us.
>> You can make the case that this second definition is an illusory
>> corollary of the first, but the fact is that artists have long used this
>> second definition and thus it is customary usage in photography.
>
> This follows from my above comments
>
> Colin

Finally, someone has thought this at least beyond the regurgitated dogma
handed out in these parts. Kudos!

I'm curious to know if you thought this was a difficult matter, or was
it obvious to you that part of the story wasn't being considered?

Will D.
Anonymous
January 2, 2005 11:23:22 PM

Archived from groups: rec.photo.digital.slr-systems (More info?)

Will D. <willd@no.spam> wrote:

> Finally, someone has thought this at least beyond the regurgitated dogma
> handed out in these parts. Kudos!
>
> I'm curious to know if you thought this was a difficult matter, or was
> it obvious to you that part of the story wasn't being considered?

I still can't figure out what it is you're getting at.

This discussion always starts with someone putting forth the misconception
that perspective is a function of focal length. It is not. It still is
not even taking into account what you're talking about here.

Moreover, I am unable to figure out how what you're talking about here
matters in any way whatsoever to the topic. Now, granted, I've tried the
"correct viewing distance" thing before, and I just can't see it -- I can
look at a picture shoved right up against my nose or from across the room,
and it looks exactly the same to me. I am unable to see this effect.
However, I'm willing to accept that everyone else can -- but even with
that accepted, I can't see what it has to do with anything. It doesn't
change the perspective of the image. It doesn't affect the image in any
way whatsoever.

--
Jeremy | jeremy@exit109.com
Anonymous
January 3, 2005 12:28:38 AM

Archived from groups: rec.photo.digital.slr-systems (More info?)

"Will D." wrote:
>
> On 2005-01-02, Colin D <ColinD@killspam.127.0.0.1> wrote:
> >
> >
> > "Will D." wrote:
> >>
> >><snip>
> >> An illusion is an apparency that is the function of the interpretive
> >> mind, which is classically dispelled by blinking one's eyes and taking
> >> another look. Big noses and tiny ears in portraits taken with wide
> >> angle lenses cannot be dispelled by blinking one's eyes. Compared to
> >> what one sees with unaided vision, they constitute distortions.
> >>
> > This effect - small ears and big noses - is because the viewing distance
> > of the photo is wrong. The 'correct' viewing distance of any image is
> > equal to the focal length of the taking lens times the subsequent
> > magnification applied to the image. At this distance - and only this
> > distance - the relative sizes of objects in the photograph will
> > correspond with what was seen by the lens when taking the shot. If you
> > view the image from too close, the perspective appears flattened, and
> > from too far away the perspective appears exaggerated. This is the
> > source of your ears/nose problem. Example: a portrait taken with a 24mm
> > lens on 35mm film, and enlarged to 10x8 will require a viewing distance
> > of 24mm x 8 (the degree of enlargement). This comes out to about 7.5
> > inches, much closer than one usually views a 10x8 print. However, if
> > you do view the image at that distance, the perspective will look right.
> > One definition of a 'normal' lens is when images from that lens, viewed
> > at the usual distance for the size of print, appears to have normal
> > perspective.
> >
> >> I defined the second usage of the term "perspective" as caused by
> >> distortion, because we are accustomed to gauging our position in our
> >> environment, in part, by the relative size of the objects around us.
> >> You can make the case that this second definition is an illusory
> >> corollary of the first, but the fact is that artists have long used this
> >> second definition and thus it is customary usage in photography.
> >
> > This follows from my above comments
> >
> > Colin
>
> Finally, someone has thought this at least beyond the regurgitated dogma
> handed out in these parts. Kudos!
>
> I'm curious to know if you thought this was a difficult matter, or was
> it obvious to you that part of the story wasn't being considered?
>
> Will D.

Sorry about not snipping here, but I couldn't without losing the trail.

I grew up with photographic matters way back in the 1950's, when the
Ilford Manual and similar publications were the bible of photography.
All of this perspective, DoF, etc. became an integral part of my
photographic experience, and is just second nature to me now. So, it
isn't difficult, I don't have to think about it, it's just 'there'. I
don't mean to sound boastful or arrogant, it's just the results of
lifetime learning and doing.

Colin.
Anonymous
January 3, 2005 2:20:09 AM

Archived from groups: rec.photo.digital.slr-systems (More info?)

On 2005-01-02, Jeremy Nixon <jeremy@exit109.com> wrote:
> Will D. <willd@no.spam> wrote:
>
>> Finally, someone has thought this at least beyond the regurgitated dogma
>> handed out in these parts. Kudos!
>>
>> I'm curious to know if you thought this was a difficult matter, or was
>> it obvious to you that part of the story wasn't being considered?
>
> I still can't figure out what it is you're getting at.
>
> This discussion always starts with someone putting forth the misconception
> that perspective is a function of focal length. It is not. It still is
> not even taking into account what you're talking about here.

Well okay, let me give this another try, then.

The dogma is that perspective has a single definition: the view from a
location. A change in the former necessitates a change in the latter.
Also included in this dogma is the assertion that this single statement
is all that is relevant.

I'm claiming that this last assertion is false. Here's why:

There are arguably two different definitions of perspective, though they
are related. The first and dogmatic is the scientific definition having
to do with the physics of optical trains, etc. The second, and here
ignored, definition is that used by artists, and has to do not with the
science of optics, but with the experience of the observer.

In support of this contention is the fact that painters produce images
using only their own eyes and dexterity with a paint brush. They
deliberately create artistic perspectives that may or may not be
optically reproducible, and they do so to affect the viewer in some
intended manner. It's not crystal clear that all artists see this the
same way, but it seems to me that they all are using the same human
facility, which is that we orient ourselves in our environment by means
of an (automatic) analysis of perceived perspective.

In this, we note what we can and cannot see as compared to what we know
exists, and we note the relative perceived size of objects that we have
had occasion to measure objectively (if only from some standard
distance, etc). Artists alter our sense of orientation wrt the scene in
their work. And so forth.

So these two definitions have a common basis, and that is the human
experience. One, the scientific version, is specific as a definition of
objective phenomenon. Cameras can and do have a perspective independent
of the user. The other, the artist's version, is specific as a
definition of a human experience, which is our most common way of
locating ourselves in our environment. The important thing about this,
in this thread, is that artistic perspective can be distorted, and any
distortion does affect the viewer, though perhaps not predictably in all
cases.

Having argued this dual definition, what I've said is that the invariant
angle of view of an SLR viewfinder creates such a distortion, and that
newbies trying to figure all this out for themselves usually do not
"get" this fact. The dogma does not satisfy their experience because it
either ignores or refutes that experience, neither of which is
reasonable as far as I'm concerned. Photographers are, or can be,
artists, and the use of the second definition is perfectly legitimate in
photography, and so the claim that it is not, or does not exist, is
invalid and such an assertion is false.

> Moreover, I am unable to figure out how what you're talking about here
> matters in any way whatsoever to the topic. Now, granted, I've tried the
> "correct viewing distance" thing before, and I just can't see it -- I can
> look at a picture shoved right up against my nose or from across the room,
> and it looks exactly the same to me. I am unable to see this effect.
> However, I'm willing to accept that everyone else can -- but even with
> that accepted, I can't see what it has to do with anything. It doesn't
> change the perspective of the image. It doesn't affect the image in any
> way whatsoever.

The topic here is not the science of optics, it is the experience of the
effect of uncompensated angle of view presentations, which has much to
do with the art of photography. The topicality is based on the fact
that new people sometimes consider DSLRs as a way of getting out of
snapshooting and into photography, and come here to learn. Part of that
experience has to do with addressing questions directly that they have
ignored before. This issue is one of those questions, which is why my
OP.

You say the print looks exactly the same regardless of viewing distance,
and so it should. The question is whether or not it looks natural, or
does it look distorted: the relative size of objects not corresponding
to what might be expected, creating the impression of exaggerated or
compressed distances.

Of course, maybe this is irrelevant to you, but it doesn't seem irrelevant
to newbies, at least in my experience.

Here's a question for you. You've noticed the engraved message in the
passenger side mirrors of modern cars? It says something like "Warning!
Objects in mirror are closer than they appear!" Do you consider the
image in such mirrors to be distorted? Most people do, I think. Do you
think this is important? If you don't, why not? Or maybe better yet,
if you do, how do you explain this?

Will D.
Anonymous
January 3, 2005 3:18:12 AM

Archived from groups: rec.photo.digital.slr-systems (More info?)

On 2005-01-02, Colin D <ColinD@killspam.127.0.0.1> wrote:

<snip>
> Sorry about not snipping here, but I couldn't without losing the trail.

No problem. I just turn the shears lose :) 

> I grew up with photographic matters way back in the 1950's, when the
> Ilford Manual and similar publications were the bible of photography.
> All of this perspective, DoF, etc. became an integral part of my
> photographic experience, and is just second nature to me now. So, it
> isn't difficult, I don't have to think about it, it's just 'there'. I
> don't mean to sound boastful or arrogant, it's just the results of
> lifetime learning and doing.
>
> Colin.

Sounds like me, I guess. I've had schooling, but these are the obvious
basics, seems to me. I read Ansel's books, and Dad had a sheet film
camera. Much the same sort of thing as the stuff in Ilford and Kodak
books, I suppose.

I just figure that answers that blow off questions aren't good answers.
To me, a valid answer has to satisfy the existence of the question, if
nothing else, and the answers given hereabouts to newbies about
perspective don't do that.

Anyway, glad to see agreement that this is all basic photographic
knowledge that anyone should understand from a bit of reading and
experience.

Will D.
Anonymous
January 3, 2005 4:03:24 AM

Archived from groups: rec.photo.digital.slr-systems (More info?)

Will D. <willd@no.spam> wrote:

> In this, we note what we can and cannot see as compared to what we know
> exists, and we note the relative perceived size of objects that we have
> had occasion to measure objectively (if only from some standard
> distance, etc). Artists alter our sense of orientation wrt the scene in
> their work. And so forth.

Yes, I agree; an artist using a media where the image is created from
"scratch" can play with perspective as you say. However, a photographer
cannot, so I don't see it as terribly applicable.

However, although a photograph does only display what is actually visible,
it doesn't include enough information for a human to reproduce the experience
of seeing the scene in person, in terms of orienting himself and determining
what goes where. Our eyes and brains use things that aren't included in a
flat photograph to do that. This allows some degree of optical illusion in
perspective, but still only in a way that doesn't change what is actually
there. The camera records what is visible from a certain viewpoint, and
that's it.

> Having argued this dual definition, what I've said is that the invariant
> angle of view of an SLR viewfinder creates such a distortion, and that
> newbies trying to figure all this out for themselves usually do not
> "get" this fact. The dogma does not satisfy their experience because it
> either ignores or refutes that experience, neither of which is
> reasonable as far as I'm concerned.

I also agree with this, but I think we differ on an underlying cause. In
the old days of film, it was not a problem to describe perspective in terms
of focal length, because a given focal length always meant the same thing
to 35mm camera users. Nowadays, you simply cannot use focal length to
describe perspective, because focal length can't describe the angle of
view on a digital camera -- lenses of the same focal length can have very
different views on different cameras, even the exact *same* lens used on
different cameras. Unfortunately, lots of stuff, including written stuff
in formerly-authoritative texts, still exists talking about perspective
of certain lenses, and all of that stuff is now simply not true.

If I put my 50mm lens on my 35mm SLR, and then put it on my digital SLR,
it will not give me the same field of view on both cameras. On the
digital it will behave exactly the same as a 75mm lens would on the 35mm
camera, with regard to field of view (not depth of field, which is a
whole other topic). If you want to consider perspective as a function
of focal length, you must then think of it as a 75mm lens when using it
on the digital SLR (at least a Nikon one) because that's how it will
work. Given identical framing (and thus differing camera-to-subject
distance) with that lens on the two cameras, the perspective will be
different.

So, I think people get confused because they have learned about perspective
either back when you *could* describe angle of view by focal length, or
from things written at that time. Back in the day, if you were writing
for 35mm film users, you could say that 50mm is a "normal lens" and be
right. You can't do that any more because it's not going to be right.

> You say the print looks exactly the same regardless of viewing distance,
> and so it should. The question is whether or not it looks natural, or
> does it look distorted: the relative size of objects not corresponding
> to what might be expected, creating the impression of exaggerated or
> compressed distances.

That's what I mean. To me, a wide-angle shot with "distortion" at the
edges (I put "distortion" in quotes because it's not really distortion,
and I've been scolded for using that word to describe it here already,
but I can't think of a better word to use) still looks identically
distorted no matter where the print is relative to my eyes. But since
everyone else says it doesn't, fine; this is something I haven't learned
to see, like those pictures in the mall with all the dots that are
supposed to become something if you stare at them long enough, but
which always (to me) just look like a bunch of dots.

But if that does work, it works because you're changing the angle at which
you're seeing certain parts of the scene, which is basically the same
thing you do when you move the camera. The wide-angle "distortion" is
caused by seeing parts of the scene at different angles, but then
projecting that resulting image onto a flat surface. So that doesn't
mean that something other than viewpoint changes perspective; you're
just changing the viewpoint.

> Here's a question for you. You've noticed the engraved message in the
> passenger side mirrors of modern cars? It says something like "Warning!
> Objects in mirror are closer than they appear!" Do you consider the
> image in such mirrors to be distorted? Most people do, I think. Do you
> think this is important? If you don't, why not? Or maybe better yet,
> if you do, how do you explain this?

That is distortion, due to the mirror being convex. So? It's basically
the same thing; it's a "wide angle" mirror.

--
Jeremy | jeremy@exit109.com
Anonymous
January 3, 2005 12:23:20 PM

Archived from groups: rec.photo.digital.slr-systems (More info?)

"Jeremy Nixon" <jeremy@exit109.com> wrote in message
news:10tgm1qcu4ant6a@corp.supernews.com...

> This discussion always starts with someone putting forth the misconception
> that perspective is a function of focal length. It is not. It still is
> not even taking into account what you're talking about here.
>
> Moreover, I am unable to figure out how what you're talking about here
> matters in any way whatsoever to the topic. Now, granted, I've tried the
> "correct viewing distance" thing before, and I just can't see it -- I can
> look at a picture shoved right up against my nose or from across the room,
> and it looks exactly the same to me. I am unable to see this effect.
> However, I'm willing to accept that everyone else can -- but even with
> that accepted, I can't see what it has to do with anything. It doesn't
> change the perspective of the image. It doesn't affect the image in any
> way whatsoever.
>
> --
> Jeremy | jeremy@exit109.com

That was me who put that forward, Jeremy. Perhaps Jeremy, your
interpretation of 'perspective' as applied to photographing portraits is
different to the interpretation of Photographers who actually take portraits
for a living?

I made the mistake of presuming this group was frequented by photographers
and artistic people who had natural perspective appreciation as part of
their makeup. I was wrong. This thread demonstrates that a new (let me call
it 'breed') of technocrats has emerged into what has always previously been
an artistic appreciation of the many aspects of art. Artists are more
inclined to focus on the final result of what they do. Their cameras are
only tools they use to achieve a photograph. They know a 100 mm lens will
produce a portrait with better 'perspective' than your assertion that a 20mm
one can too. Many could make the portrait with or without a camera.

Technocrats are digital deviates. They embrace photography for it's
technology as much as it's picture taking ability. The statements you made
above, very clearly demonstrate you have little of the artist in you and a
lot of the technologist. I still use a portrait lens for portraits because
80, 100 mm focal length lenses produce a better perspective to the
photograph. That is my statement. I learned it from masters of photography,
probably before you were born and you can't change it now with all your
mathematics and science.

For me that is all there is too it. For you, it seems there is a myriad of
mathematics and defined precision that portrait photography simply doesn't
have any use for. You can't 'see' a change in the perspective because you
don't have the ability to 'see' it. Do you understand that much? You are not
able to even comprehend the meaning of what I originally said, much less put
your argument into perspective when discussing a portrait.

Doug
Anonymous
January 3, 2005 1:20:32 PM

Archived from groups: rec.photo.digital.slr-systems (More info?)

Ryadia wrote:

> able to even comprehend the meaning of what I originally said, much less put
> your argument into perspective when discussing a portrait.

The only point that matters Doug, is that perspective is what perspective is,
and it is not anything else but what it is. Several people have set out
examples for you to follow in order to understand it, in general and in the
context of portraits. The exercises Gisle and I, and others proposed would
clearly demonstrate the principle if you would try them.

Delving into an alternate meaning based on 'portraits', does not make your
definition correct in any way. Perspective is a matter of distance from the
viewer to the subject. Period. Focal length has nothing to do with it. Period.

What you say about lenses around 100mm (35mm frame) being preferred for
portraits is true. And it is entirely based on perspective, that is true. Try
a full frame of a head/shoulders shot with a 50mm and it is obvious why a longer
FL is preferred. Stand back where you shoot the 100 for a full frame head
shoulders and shoot with the 50mm. Crop the result. It will have the same
perspective and look as the 100mm.

You will find that such admission will not change your ability to make
portraits, and it might even improve your photography in some other context.

Cheers,
Alan.


--
-- r.p.e.35mm user resource: http://www.aliasimages.com/rpe35mmur.htm
-- r.p.d.slr-systems: http://www.aliasimages.com/rpdslrsysur.htm
-- [SI] gallery & rulz: http://www.pbase.com/shootin
-- e-meil: there's no such thing as a FreeLunch.
Anonymous
January 3, 2005 3:10:20 PM

Archived from groups: rec.photo.digital.slr-systems (More info?)

Jeremy Nixon <jeremy@exit109.com> writes:

> That's what I mean. To me, a wide-angle shot with "distortion" at the
> edges (I put "distortion" in quotes because it's not really distortion,
> and I've been scolded for using that word to describe it here already,
> but I can't think of a better word to use) still looks identically
> distorted no matter where the print is relative to my eyes. But since
> everyone else says it doesn't, fine; this is something I haven't learned
> to see, like those pictures in the mall with all the dots that are
> supposed to become something if you stare at them long enough, but
> which always (to me) just look like a bunch of dots.

I think you'd be able to see it much more easily if you closed one
eye. Your brain has various compensatory mechanisms, you know.

B>
Anonymous
January 3, 2005 3:15:02 PM

Archived from groups: rec.photo.digital.slr-systems (More info?)

"Ryadia" <ryadia@hotmail.com> writes:

> I made the mistake of presuming this group was frequented by photographers
> and artistic people who had natural perspective appreciation as part of
> their makeup. I was wrong. This thread demonstrates that a new (let me call
> it 'breed') of technocrats has emerged into what has always previously been
> an artistic appreciation of the many aspects of art. Artists are more
> inclined to focus on the final result of what they do. Their cameras are
> only tools they use to achieve a photograph. They know a 100 mm lens will
> produce a portrait with better 'perspective' than your assertion that a 20mm
> one can too. Many could make the portrait with or without a camera.

Garbage. You've started whining about art and denouncing people who
actually have a real appreciation for the means by which an image is
formed on film.

If you want to pretent that there's a magic portrait land in which
perspective is a mysterious and wonderful thing, unaffected by, say,
the straight-line nature of light then go ahead. The rest of us are
going to sit back and continue concluding that you're an idiot.

B>
Anonymous
January 3, 2005 9:16:18 PM

Archived from groups: rec.photo.digital.slr-systems (More info?)

"Jeremy Nixon" <jeremy@exit109.com> wrote in message
news:10thbt1k3c7smdb@corp.supernews.com...

>
> What you really mean is that you like the perspective you get when you use
> a 100mm lens on a 35mm camera from portrait distance. This doesn't say
> much about what you'll get with a 100mm lens at portrait distance with
> an APS-size sensor.
>
> --
> Jeremy | jeremy@exit109.com

You get the same depth of field Jeremy. And that is precisely what I started
with...
Originally I said something along the lines that a wide held belief that 1.6
crop factor was in fact a telephoto factor, was wrong and went on to explain
why it was so. You saw fit to take one part of what I said (about the
perspective of a portrait being lost in that presumption) and make your own
entertainment out of it. I really don't care too much if you are a Rhodes
scholar in optical engineering...

You really need to take into consideration the thread which you hijack
before you get your rocks off on people who are not engineers. I post here
as a practicing Professional Photographer with 45 years in the trade. Yes,
when I was apprenticed as a Photographer it was a trade. You seem to think
my training and those before me (many of whom are well respected and
published authorities on the subject) who actually have a grasp on the
perspective of a portrait should all now bow to the engineers statement that
perspective is an engineering term and it is not to be tied to focal length.
Somehow the ditty of how many Engineers are needed to change a light bulb
comes to mind here.

Doug
Anonymous
January 3, 2005 9:16:19 PM

Archived from groups: rec.photo.digital.slr-systems (More info?)

Ryadia <ryadia@hotmail.com> wrote:
> "Jeremy Nixon" <jeremy@exit109.com> wrote in message
>
>> What you really mean is that you like the perspective you get when you use
>> a 100mm lens on a 35mm camera from portrait distance. This doesn't say
>> much about what you'll get with a 100mm lens at portrait distance with
>> an APS-size sensor.
>
> You get the same depth of field Jeremy.

No, you don't. Still, depth of field has nothing to do with perspective.

> Originally I said something along the lines that a wide held belief that 1.6
> crop factor was in fact a telephoto factor, was wrong and went on to explain
> why it was so.

But it is, in every way that actually matters, and the explanations you have
offered have amounted to nothing more than "I've been a photographer since
before your great-grandfather was born and I say so". Oh yeah, plus the
whole "magic perspective" thing you get when shooting a portrait that doesn't
happen with any other subject.

> You really need to take into consideration the thread which you hijack
> before you get your rocks off on people who are not engineers.

But *I'm* not an engineer.

--
Jeremy | jeremy@exit109.com
Anonymous
January 4, 2005 1:15:11 AM

Archived from groups: rec.photo.digital.slr-systems (More info?)

On 2005-01-02, Ryadia <ryadia@hotmail.com> wrote:
>
> "Jeremy Nixon" <jeremy@exit109.com> wrote in message
> news:10tgm1qcu4ant6a@corp.supernews.com...
>
>> This discussion always starts with someone putting forth the misconception
>> that perspective is a function of focal length. It is not. It still is
>> not even taking into account what you're talking about here.
>>
>> Moreover, I am unable to figure out how what you're talking about here
>> matters in any way whatsoever to the topic. Now, granted, I've tried the
>> "correct viewing distance" thing before, and I just can't see it -- I can
>> look at a picture shoved right up against my nose or from across the room,
>> and it looks exactly the same to me. I am unable to see this effect.
>> However, I'm willing to accept that everyone else can -- but even with
>> that accepted, I can't see what it has to do with anything. It doesn't
>> change the perspective of the image. It doesn't affect the image in any
>> way whatsoever.
>>
>> --
>> Jeremy | jeremy@exit109.com
>
> That was me who put that forward, Jeremy. Perhaps Jeremy, your
> interpretation of 'perspective' as applied to photographing portraits is
> different to the interpretation of Photographers who actually take portraits
> for a living?

Whoa! I started this thread, and Jeremy was responding to my posts.

> I made the mistake of presuming this group was frequented by photographers
> and artistic people who had natural perspective appreciation as part of
> their makeup. I was wrong. This thread demonstrates that a new (let me call
> it 'breed') of technocrats has emerged into what has always previously been
> an artistic appreciation of the many aspects of art. Artists are more
> inclined to focus on the final result of what they do. Their cameras are
> only tools they use to achieve a photograph. They know a 100 mm lens will
> produce a portrait with better 'perspective' than your assertion that a 20mm
> one can too. Many could make the portrait with or without a camera.

Well, I think you're right about techie geeks, but you have to honor
their insistence on accuracy. All artists have to deal with technology,
you know. Painters that don't know the science behind pigments and
emulsions etc, are going to screw up unnecessarily, just like
photographers who don't understand the science behind their gear.

Photographers who think that a 100mm lens is a portrait lens don't know
what they're talking about. Photographers can say that their 100mm lens
allows them to get useful portrait framing at the distance they like on
a 35mm camera, but they know that it is the angle of view that is the
active parameter. Put a 100mm lens on a 6x7 and you've got a standard
lens, or thereabouts. Put it on a 4x5 and you've got a moderate wide
angle lens. Put it on a digital with a smaller sensor, and you've got a
moderate telephoto lens.

But you know all this, don't you? At least, I sure hope you do!

> Technocrats are digital deviates. They embrace photography for it's
> technology as much as it's picture taking ability. The statements you made
> above, very clearly demonstrate you have little of the artist in you and a
> lot of the technologist. I still use a portrait lens for portraits because
> 80, 100 mm focal length lenses produce a better perspective to the
> photograph. That is my statement. I learned it from masters of photography,
> probably before you were born and you can't change it now with all your
> mathematics and science.

The question here is: Do you know why, and if so, what is your problem
with technical discussions in an equipment newsgroup?

> For me that is all there is too it. For you, it seems there is a myriad of
> mathematics and defined precision that portrait photography simply doesn't
> have any use for. You can't 'see' a change in the perspective because you
> don't have the ability to 'see' it. Do you understand that much? You are not
> able to even comprehend the meaning of what I originally said, much less put
> your argument into perspective when discussing a portrait.
>
> Doug

Perhaps portrait photography is all you know how to do? Doesn't sound
like it from your accounts of shooting in extreme conditions, or are you
doing wildlife portraits?

Will D.
Anonymous
January 4, 2005 1:15:12 AM

Archived from groups: rec.photo.digital.slr-systems (More info?)

Will D. wrote:
> On 2005-01-02, Ryadia <ryadia@hotmail.com> wrote:
>>
>> "Jeremy Nixon" <jeremy@exit109.com> wrote in message
>> news:10tgm1qcu4ant6a@corp.supernews.com...
>>
>>> This discussion always starts with someone putting forth the
>>> misconception that perspective is a function of focal length. It
>>> is not. It still is not even taking into account what you're
>>> talking about here.
>>>
>>> Moreover, I am unable to figure out how what you're talking about
>>> here matters in any way whatsoever to the topic. Now, granted,
>>> I've tried the "correct viewing distance" thing before, and I just
>>> can't see it -- I can look at a picture shoved right up against my
>>> nose or from across the room, and it looks exactly the same to me.
>>> I am unable to see this effect. However, I'm willing to accept that
>>> everyone else can -- but even with that accepted, I can't see what
>>> it has to do with anything. It doesn't change the perspective of
>>> the image. It doesn't affect the image in any way whatsoever.
>>>

Doug sayed:

>>
>> That was me who put that forward, Jeremy. Perhaps Jeremy, your
>> interpretation of 'perspective' as applied to photographing
>> portraits is different to the interpretation of Photographers who
>> actually take portraits for a living?
>

Will D. interjected:

> Whoa! I started this thread, and Jeremy was responding to my posts.
>

So, did you get your answer?

If not, how many more thousands of lines do you think it will take?

I suggest that everyone who has an interest in this thread now amounts
to some negative number, that the participants have all established
their positions (heh) and indicated the likelihood of accommodating any
others.

That's my perspective on it.


--
Frank ess
Anonymous
January 4, 2005 3:00:18 AM

Archived from groups: rec.photo.digital.slr-systems (More info?)

On 2005-01-03, Jeremy Nixon <jeremy@exit109.com> wrote:
> Will D. <willd@no.spam> wrote:
>
>> In this, we note what we can and cannot see as compared to what we know
>> exists, and we note the relative perceived size of objects that we have
>> had occasion to measure objectively (if only from some standard
>> distance, etc). Artists alter our sense of orientation wrt the scene in
>> their work. And so forth.
>
> Yes, I agree; an artist using a media where the image is created from
> "scratch" can play with perspective as you say. However, a photographer
> cannot, so I don't see it as terribly applicable.
>
> However, although a photograph does only display what is actually visible,
> it doesn't include enough information for a human to reproduce the experience
> of seeing the scene in person, in terms of orienting himself and determining
> what goes where. Our eyes and brains use things that aren't included in a
> flat photograph to do that. This allows some degree of optical illusion in
> perspective, but still only in a way that doesn't change what is actually
> there. The camera records what is visible from a certain viewpoint, and
> that's it.

Well, to the extent that people learn to ignore "optical illusion in
perspective", it becomes (or can become) of less importance that perhaps
you inferred from my comments. Certainly people who know little or
nothing about photography easily ignore the issue. But my point was
that newbies trying to extent their photographic knowledge and skills
will come to ask what's going on, and to state that nothing is going on
is to suggest to them that what they see is non-existent. And that's
not the case.

>> Having argued this dual definition, what I've said is that the invariant
>> angle of view of an SLR viewfinder creates such a distortion, and that
>> newbies trying to figure all this out for themselves usually do not
>> "get" this fact. The dogma does not satisfy their experience because it
>> either ignores or refutes that experience, neither of which is
>> reasonable as far as I'm concerned.
>
> I also agree with this, but I think we differ on an underlying cause. In
> the old days of film, it was not a problem to describe perspective in terms
> of focal length, because a given focal length always meant the same thing
> to 35mm camera users. Nowadays, you simply cannot use focal length to
> describe perspective, because focal length can't describe the angle of
> view on a digital camera -- lenses of the same focal length can have very
> different views on different cameras, even the exact *same* lens used on
> different cameras. Unfortunately, lots of stuff, including written stuff
> in formerly-authoritative texts, still exists talking about perspective
> of certain lenses, and all of that stuff is now simply not true.
>
> If I put my 50mm lens on my 35mm SLR, and then put it on my digital SLR,
> it will not give me the same field of view on both cameras. On the
> digital it will behave exactly the same as a 75mm lens would on the 35mm
> camera, with regard to field of view (not depth of field, which is a
> whole other topic). If you want to consider perspective as a function
> of focal length, you must then think of it as a 75mm lens when using it
> on the digital SLR (at least a Nikon one) because that's how it will
> work. Given identical framing (and thus differing camera-to-subject
> distance) with that lens on the two cameras, the perspective will be
> different.
>
> So, I think people get confused because they have learned about perspective
> either back when you *could* describe angle of view by focal length, or
> from things written at that time. Back in the day, if you were writing
> for 35mm film users, you could say that 50mm is a "normal lens" and be
> right. You can't do that any more because it's not going to be right.

I'm talking about newbies that have never used an SLR of any kind. They
know nothing of the traditional focal length / angle of view
correspondence. That's only for people who've used an SLR enough to
know better.

>> You say the print looks exactly the same regardless of viewing distance,
>> and so it should. The question is whether or not it looks natural, or
>> does it look distorted: the relative size of objects not corresponding
>> to what might be expected, creating the impression of exaggerated or
>> compressed distances.
>
> That's what I mean. To me, a wide-angle shot with "distortion" at the
> edges (I put "distortion" in quotes because it's not really distortion,
> and I've been scolded for using that word to describe it here already,
> but I can't think of a better word to use) still looks identically
> distorted no matter where the print is relative to my eyes. But since
> everyone else says it doesn't, fine; this is something I haven't learned
> to see, like those pictures in the mall with all the dots that are
> supposed to become something if you stare at them long enough, but
> which always (to me) just look like a bunch of dots.

I use the word distortion without quotes because that's what it is.
It's not an optical illusion at all. It's what happens when one tries
to force one angle of view into another angle of view. And you're right
when you observe that the print looks equally distorted from any viewing
distance if, and probably only if, you cannot suspend your sense of
current physical environment enough to "be with/in" the scene displayed
by the print.

I've no idea what percentage of people can't do that, but I've got to
assume that a goodly percentage can, else visual art would not be the
universally appreciated commodity it has long been.

> But if that does work, it works because you're changing the angle at which
> you're seeing certain parts of the scene, which is basically the same
> thing you do when you move the camera. The wide-angle "distortion" is
> caused by seeing parts of the scene at different angles, but then
> projecting that resulting image onto a flat surface. So that doesn't
> mean that something other than viewpoint changes perspective; you're
> just changing the viewpoint.

Well, yes, of course. The scientific definition of perspective always
obtains. As far as flat surfaces are concerned, one might think of the
observed image as an image plane, but I'm not clear that this is really
relevant. In one case it's the ground glass, and the other it's a print
surface, but that doesn't mean that the viewer stops trying to extract
depth information. And it's the effect on the viewer that is primary to
my original statement.

And it's at that point that the second definition becomes relevant.

>> Here's a question for you. You've noticed the engraved message in the
>> passenger side mirrors of modern cars? It says something like "Warning!
>> Objects in mirror are closer than they appear!" Do you consider the
>> image in such mirrors to be distorted? Most people do, I think. Do you
>> think this is important? If you don't, why not? Or maybe better yet,
>> if you do, how do you explain this?
>
> That is distortion, due to the mirror being convex. So? It's basically
> the same thing; it's a "wide angle" mirror.

Exactly. It's one angle of view being forced into another angle of
view, which is the cause of the distortion. Now, here the flat surface
issue is relevant. Do you see the mirror as a flat surface? I don't.
I'm accustomed to extracting depth information from a mirror because
normally the mirror is planar. Of course there is an adjustment to be
made because of the viewer to mirror distance, but most people are able
to make that adjustment automatically, I think.

I think we've come to agree that the issue is real, whether or not it is
relevant here in general or specifically in the case of newbies
learning. We can debate the particulars and details, but it's that
agreement of the reality of the issue that I was seeking.

Will D.
Anonymous
January 4, 2005 4:24:53 PM

Archived from groups: rec.photo.digital.slr-systems (More info?)

Ryadia wrote:
<various snips>
> Artists are more
> inclined to focus on the final result of what they do. Their cameras are
> only tools they use to achieve a photograph. They know a 100 mm lens will
> produce a portrait with better 'perspective' than your assertion that a 20mm
> one can too. Many could make the portrait with or without a camera.
>
> I still use a portrait lens for portraits because
> 80, 100 mm focal length lenses produce a better perspective to the
> photograph. That is my statement. I learned it from masters of photography,
> probably before you were born and you can't change it now with all your
> mathematics and science.
>
Yes, I agree with what you say here, Doug, those lenses will produce a
better perspective in the final image than a shorter lens - *but* the
reason has nothing to do with the lens characteristics. It is entirely
due to the position you take with respect to the subject that produces
the desirable perspective. The longer lens merely lets you compose the
image within the frame from your viewing position. A shorter lens from
the same position will produce the same perspective, but a smaller image
of the subject.

The natural thing with any lens is to reasonably fill the frame with the
subject. Short lens, closer to subject. Long lens, further from
subject. The perspective is generated by the camera postion, not the
lens.

In my photographic experience, largely before good zooms were available,
a protog. would move around to get his desired viewpoint/perspective,
and then choose a lens that would reasonably fill the frame with his
envisaged shot. Today, with passable to good zooms available, he should
still walk around to get the best position, and then zoom to frame the
shot (Most non-pro's just stand where they first saw the shot and zoom
away, ignoring perspective entirely).

I can see that it is a kind of mental shortcut to associate perspective
with given lenses, and from that to accept that the lens is the source
of perspective. I find it much better to realise that perspective is
the result of viewpoint, and then choose the optics to get the shot.
More freedom that way.

Colin.
Anonymous
January 4, 2005 11:57:16 PM

Archived from groups: rec.photo.digital.slr-systems (More info?)

On 2005-01-03, Frank ess <frank@fshe2fs.com> wrote:

> Will D. interjected:
>
>> Whoa! I started this thread, and Jeremy was responding to my posts.
>>
>
> So, did you get your answer?
>
> If not, how many more thousands of lines do you think it will take?
>
> I suggest that everyone who has an interest in this thread now amounts
> to some negative number, that the participants have all established
> their positions (heh) and indicated the likelihood of accommodating any
> others.
>
> That's my perspective on it.

Wasn't looking for an answer.

What made you think I was looking for one? What question did you fancy
I was asking? Well, I'd ask what sort of answer you think I'm seeking,
but don't think I'm interested in anything taking thousands of lines.

Do you suppose that you actually understood what this thread was all
about? If you think I was asking a question, either you didn't read the
thread, or you're short on comprehension of what you did read. If
you're interested, I suggest you go back and find out what you didn't
get, and let me know. I'd be glad to explain what you didn't
understand.

Will D.
Anonymous
January 5, 2005 7:09:38 AM

Archived from groups: rec.photo.digital.slr-systems (More info?)

On 2005-01-04, Colin D <ColinD@killspam.127.0.0.1> wrote:
>
>
> Ryadia wrote:
><various snips>
>> Artists are more
>> inclined to focus on the final result of what they do. Their cameras are
>> only tools they use to achieve a photograph. They know a 100 mm lens will
>> produce a portrait with better 'perspective' than your assertion that a 20mm
>> one can too. Many could make the portrait with or without a camera.
>>
>> I still use a portrait lens for portraits because
>> 80, 100 mm focal length lenses produce a better perspective to the
>> photograph. That is my statement. I learned it from masters of photography,
>> probably before you were born and you can't change it now with all your
>> mathematics and science.
>>
> Yes, I agree with what you say here, Doug, those lenses will produce a
> better perspective in the final image than a shorter lens - *but* the
> reason has nothing to do with the lens characteristics. It is entirely
> due to the position you take with respect to the subject that produces
> the desirable perspective. The longer lens merely lets you compose the
> image within the frame from your viewing position. A shorter lens from
> the same position will produce the same perspective, but a smaller image
> of the subject.
>
> The natural thing with any lens is to reasonably fill the frame with the
> subject. Short lens, closer to subject. Long lens, further from
> subject. The perspective is generated by the camera postion, not the
> lens.
>
> In my photographic experience, largely before good zooms were available,
> a protog. would move around to get his desired viewpoint/perspective,
> and then choose a lens that would reasonably fill the frame with his
> envisaged shot. Today, with passable to good zooms available, he should
> still walk around to get the best position, and then zoom to frame the
> shot (Most non-pro's just stand where they first saw the shot and zoom
> away, ignoring perspective entirely).
>
> I can see that it is a kind of mental shortcut to associate perspective
> with given lenses, and from that to accept that the lens is the source
> of perspective. I find it much better to realise that perspective is
> the result of viewpoint, and then choose the optics to get the shot.
> More freedom that way.
>
> Colin.

Possibly what is missing here is an understanding of why we do
portraiture like we do. There is a reason for it.

Consider the nature of a portrait. It is a formal image, intended for
posterity. We can ask: what is the essence, if any, of a formal image?
A reasonable answer is that it is a public image, intended for viewing
by unknown people now and in the future. The key attribute here is
"public".

A public image is intended to be what the public would see if the
subject were present *in public*. What that means is that the viewer
would be expected to see the subject as he would be seen to comport
himself in public, and one of the things that has long been the case, at
least here in the west, is that in public, one maintains one's personal
space, wherever possible. That's one's personal "comfort zone", if you
will.

We are used to perceiving faces of those with which we have only a
public relationship at the distance mandated by that personal space.
Painters and portraitists work at almost exactly that distance. It's
worth noting that the more lofty the public persona, the greater the
distance, usually but not always entailing the inclusion of more space.

Now contrast this with intimate images. Some generic image formula
comes to mind: get the eye in focus and let the rest of the face fade
out of focus, often shot from close enough so that the manipulation of
the features needs to deal with the big nose problem. Isn't it
interesting that we have no problem with the arrangement of a person's
features in this case!? There can be several reasons for this, seem's
to me. One is the obvious personal intimacy of established sexual
relationships. Another is the unwanted intimacy of those we might
consider undesireable. "In your face" shots of the poor and homeless,
and those who don't warrant respect, etc.

The fact is, I suggest, that it is convention that dictates the way we
regard the most pleasing faces, and that convention is driven by social
considerations. Fashion photography generally observes the public
distance, even when only part of the face is shown in the print. When
the features display the distortion inherent in views from an intimate
distance, people can tend to become uncomfortable unless they are
willing to accept the implications of that sort of relationship.

So what's going on here is that when we do portraiture, we establish the
courteous distance from the subject, which gives us the slightly
compressed arrangement of features that we're accustomed to seeing, and
then photographers chose the angle of view they want to fill the frame
as they like.

Yeah, irrelevant trivia, but hell, it fits this part of this thread!

Will D.
Anonymous
January 5, 2005 10:58:25 PM

Archived from groups: rec.photo.digital.slr-systems (More info?)

"Alan Browne" <alan.browne@freelunchVideotron.ca> wrote in message
news:crbnrr$b72$1@inews.gazeta.pl...
> Ryadia wrote:
>
> > able to even comprehend the meaning of what I originally said, much less
put
> > your argument into perspective when discussing a portrait.
>
> The only point that matters Doug, is that perspective is what perspective
is,
> and it is not anything else but what it is. > You will find that such
admission will not change your ability to make
> portraits, and it might even improve your photography in some other
context.
>
> Cheers,
> Alan

I am tempted to continue in the face if contradiction but I fear there is
no point in attempting to make the horse drink after getting it to the
water.
http://209.196.177.41/07/07-06.htm

Doug
Anonymous
January 5, 2005 10:58:26 PM

Archived from groups: rec.photo.digital.slr-systems (More info?)

Ryadia wrote:

> I am tempted to continue in the face if contradiction but I fear there is
> no point in attempting to make the horse drink after getting it to the
> water.
> http://209.196.177.41/07/07-06.htm

Very good Doug. Just showing what I said in a prior post regarding the
suitability of, eg: a 50mm used close up on a person.

Now, repeating what I and others have said:

Take the same wide angle lens and shoot from the same __distance__ away that
you would shoot the longer lens to about fill the frame. eg: the wider
lens will now show the persons head as a small part of the frame. Do this
in the center.

(eg: shoot both the 50mm and 100mm from about 2 meters away with the same
subject).

Shoot.

Last: take the 50mm shot to photoshop, crop out the shot of the person so
the head fills the frame.

Voila... same perspective and look (no figure distortions) as the long lens
at that distance.



Cheers,
Alan.

--
-- r.p.e.35mm user resource: http://www.aliasimages.com/rpe35mmur.htm
-- r.p.d.slr-systems: http://www.aliasimages.com/rpdslrsysur.htm
-- [SI] gallery & rulz: http://www.pbase.com/shootin
-- e-meil: there's no such thing as a FreeLunch.
Anonymous
January 5, 2005 11:11:35 PM

Archived from groups: rec.photo.digital.slr-systems (More info?)

"Stand back where you shoot the 100 for a full frame head
> shoulders and shoot with the 50mm. Crop the result. It will have the
same
> perspective and look as the 100mm.
>
I am beginning to grasp to stupidely simple notion that the perspective you
techno geeks are on about is the diverging line perspective where there is a
vanishing point possibly somewhere out of view. Even this could change with
different focal lengths but anyway... This is not the perspective I am
talking about. If you can identify the source of the following statement,
you might just become a better photographer yourself - Alan.

"If you're not trying to fill the frame with the subject's face, you don't
actually need a telephoto lens to avoid an unflattering perspective."

Doug
Anonymous
January 5, 2005 11:11:36 PM

Archived from groups: rec.photo.digital.slr-systems (More info?)

Ryadia wrote:

>
> "Stand back where you shoot the 100 for a full frame head
>> shoulders and shoot with the 50mm. Crop the result. It will have the
> same
>> perspective and look as the 100mm.
>>
> I am beginning to grasp to stupidely simple notion that the perspective
> you techno geeks are on about is the diverging line perspective where
> there is a vanishing point possibly somewhere out of view. Even this could
> change with different focal lengths but anyway... This is not the
> perspective I am talking about. If you can identify the source of the
> following statement, you might just become a better photographer yourself
> - Alan.
>
> "If you're not trying to fill the frame with the subject's face, you don't
> actually need a telephoto lens to avoid an unflattering perspective."

Stop spinning your wheels Doug. The notion of filling the frame was an
exercise for you to understand why a shot of 50mm at dist. x gives the same
perspective of a shot taken with a 100mm lens at dist x. Cropping the 50mm
shot after the fact will yield an identical image (minus very minor
differences in the two lens' distortions).

You appear to be in "pride" mode where you can't simply admit that you're
wrong about persepective being only, solely and nothing but the distance
between the lens and the subject. And yes, this has a much bearing on
portraits as landscapes and architectural shots.

Cheers,
Alan.



--
-- r.p.e.35mm user resource: http://www.aliasimages.com/rpe35mmur.htm
-- r.p.d.slr-systems: http://www.aliasimages.com/rpdslrsysur.htm
-- [SI] gallery & rulz: http://www.pbase.com/shootin
-- e-meil: there's no such thing as a FreeLunch.
Anonymous
January 6, 2005 1:05:46 AM

Archived from groups: rec.photo.digital.slr-systems (More info?)

Ryadia wrote:
> "Alan Browne_" <alan.browne@FreelunchVideotron.ca> wrote in message
> news:crgvnv$7ej$1@inews.gazeta.pl...
>
>>You appear to be in "pride" mode where you can't simply admit that you're
>>wrong about persepective being only, solely and nothing but the distance
>>between the lens and the subject. And yes, this has a much bearing on
>>portraits as landscapes and architectural shots.
>>
>>Cheers,
>>Alan.
>>
>
> Hold on...
> I never said perspective is "only, solely".
> What I said was using a Portrait lens of 100mm or thereabouts (to shoot a
> portrait being the unspoken intent - because that is what I do most of the
> year) would produce a better perspective than using a wide angle lens. I
> also said the reason for this was the depth of field didn't change with an
> implied telephoto crop factor so using a 50 or 75mm lens with a crop factor
> of 1.6 did not produce the shallow depth of field ("the same perspective")
> as a 100 mm lens did.

I've several times said:

-100mm (or around there, 85 - 135 is fine with me) is appropriate for
most portraits.

-I've also said that the perspective of the CROPPED portion of a shorter
focal length gives exactly the same result from THE SAME DISTANCE to the
subject as if shot from the more appropraite lens. For simplicity
sakes, I used 50mm and 100mm as example lenses and in the context of
35mm camera.

-I never made any claim about DOF being equal. I did point out what the
DOFs would be for a common CoC. (Dec 20).

THAT IS ALL. I, and others, have indicated several ways for YOU to
check this out. If you are the professional you claim to be, this
should take you no more than a few minutes to try out.

So you can go around accusing people of being amateur this, or geek
that, but the truth is that perspective is a result of distance not
focal length. And that you can't doff your hat and admit so is
indicative of your poor spirited mind. And yes, I've admitted my own
mistakes here more times than I care to count.

Cheers,
Alan
Anonymous
January 6, 2005 8:29:16 AM

Archived from groups: rec.photo.digital.slr-systems (More info?)

Ryadia <ryadia@hotmail.com> wrote:

> What I said was using a Portrait lens of 100mm or thereabouts (to shoot a
> portrait being the unspoken intent - because that is what I do most of the
> year) would produce a better perspective than using a wide angle lens. I
> also said the reason for this was the depth of field didn't change with an
> implied telephoto crop factor so using a 50 or 75mm lens with a crop factor
> of 1.6 did not produce the shallow depth of field ("the same perspective")
> as a 100 mm lens did.

Therein lies the problem, which I now believe I fully understand. You are
defining "perspective" as "depth of field", but no one else is.

--
Jeremy | jeremy@exit109.com
Anonymous
January 6, 2005 4:13:55 PM

Archived from groups: rec.photo.digital.slr-systems (More info?)

"Will D." wrote:
>
> On 2005-01-04, Colin D <ColinD@killspam.127.0.0.1> wrote:
> >
> >
> > Ryadia wrote:
> ><various snips>
> >> Artists are more
> >> inclined to focus on the final result of what they do. Their cameras are
> >> only tools they use to achieve a photograph. They know a 100 mm lens will
> >> produce a portrait with better 'perspective' than your assertion that a 20mm
> >> one can too. Many could make the portrait with or without a camera.
> >>
> >> I still use a portrait lens for portraits because
> >> 80, 100 mm focal length lenses produce a better perspective to the
> >> photograph. That is my statement. I learned it from masters of photography,
> >> probably before you were born and you can't change it now with all your
> >> mathematics and science.
> >>
> > Yes, I agree with what you say here, Doug, those lenses will produce a
> > better perspective in the final image than a shorter lens - *but* the
> > reason has nothing to do with the lens characteristics. It is entirely
> > due to the position you take with respect to the subject that produces
> > the desirable perspective. The longer lens merely lets you compose the
> > image within the frame from your viewing position. A shorter lens from
> > the same position will produce the same perspective, but a smaller image
> > of the subject.
> >
> > The natural thing with any lens is to reasonably fill the frame with the
> > subject. Short lens, closer to subject. Long lens, further from
> > subject. The perspective is generated by the camera postion, not the
> > lens.
> >
> > In my photographic experience, largely before good zooms were available,
> > a protog. would move around to get his desired viewpoint/perspective,
> > and then choose a lens that would reasonably fill the frame with his
> > envisaged shot. Today, with passable to good zooms available, he should
> > still walk around to get the best position, and then zoom to frame the
> > shot (Most non-pro's just stand where they first saw the shot and zoom
> > away, ignoring perspective entirely).
> >
> > I can see that it is a kind of mental shortcut to associate perspective
> > with given lenses, and from that to accept that the lens is the source
> > of perspective. I find it much better to realise that perspective is
> > the result of viewpoint, and then choose the optics to get the shot.
> > More freedom that way.
> >
> > Colin.
>
> Possibly what is missing here is an understanding of why we do
> portraiture like we do. There is a reason for it.
>
> Consider the nature of a portrait. It is a formal image, intended for
> posterity. We can ask: what is the essence, if any, of a formal image?
> A reasonable answer is that it is a public image, intended for viewing
> by unknown people now and in the future. The key attribute here is
> "public".
>
> A public image is intended to be what the public would see if the
> subject were present *in public*. What that means is that the viewer
> would be expected to see the subject as he would be seen to comport
> himself in public, and one of the things that has long been the case, at
> least here in the west, is that in public, one maintains one's personal
> space, wherever possible. That's one's personal "comfort zone", if you
> will.
>
> We are used to perceiving faces of those with which we have only a
> public relationship at the distance mandated by that personal space.
> Painters and portraitists work at almost exactly that distance. It's
> worth noting that the more lofty the public persona, the greater the
> distance, usually but not always entailing the inclusion of more space.
>
> Now contrast this with intimate images. Some generic image formula
> comes to mind: get the eye in focus and let the rest of the face fade
> out of focus, often shot from close enough so that the manipulation of
> the features needs to deal with the big nose problem. Isn't it
> interesting that we have no problem with the arrangement of a person's
> features in this case!? There can be several reasons for this, seem's
> to me. One is the obvious personal intimacy of established sexual
> relationships. Another is the unwanted intimacy of those we might
> consider undesireable. "In your face" shots of the poor and homeless,
> and those who don't warrant respect, etc.
>
> The fact is, I suggest, that it is convention that dictates the way we
> regard the most pleasing faces, and that convention is driven by social
> considerations. Fashion photography generally observes the public
> distance, even when only part of the face is shown in the print. When
> the features display the distortion inherent in views from an intimate
> distance, people can tend to become uncomfortable unless they are
> willing to accept the implications of that sort of relationship.
>
> So what's going on here is that when we do portraiture, we establish the
> courteous distance from the subject, which gives us the slightly
> compressed arrangement of features that we're accustomed to seeing, and
> then photographers chose the angle of view they want to fill the frame
> as they like.
>
> Yeah, irrelevant trivia, but hell, it fits this part of this thread!
>
> Will D.

Agreed 100%. What you have written about is really perspective in
action. One maintains a socially acceptable distance from a person
derived from the relationship to that person (Except in crowded
transport, or lifts, etc, where the 'look at nobody directly' phenomenon
arises), and that socially acceptable distance is mirrored in the camera
distance from the subject of the portrait. Perspective is the tool with
which we instinctively judge the appropriate distance, with or without a
camera, which is what I meant when I said that a photog moves to find
the proper perspective, then chooses his lens to suit. The viewpoint
sets the perspective, not the lens.

If you agree with that, then we're home.

Colin.
Anonymous
January 6, 2005 4:13:56 PM

Archived from groups: rec.photo.digital.slr-systems (More info?)

On 2005-01-06, Colin D <ColinD@killspam.127.0.0.1> wrote:

<snip>
> If you agree with that, then we're home.
>
> Colin.

You got in one!

Will D.
Anonymous
January 6, 2005 11:29:01 PM

Archived from groups: rec.photo.digital.slr-systems (More info?)

"Jeremy Nixon" <jeremy@exit109.com> wrote in message
news:10tpj5cgkoo4659@corp.supernews.com...
> Ryadia <ryadia@hotmail.com> wrote:
>
> > What I said was using a Portrait lens of 100mm or thereabouts (to shoot
a
> > portrait being the unspoken intent - because that is what I do most of
the
> > year) would produce a better perspective than using a wide angle lens. I
> > also said the reason for this was the depth of field didn't change with
an
> > implied telephoto crop factor so using a 50 or 75mm lens with a crop
factor
> > of 1.6 did not produce the shallow depth of field ("the same
perspective")
> > as a 100 mm lens did.
>
> Therein lies the problem, which I now believe I fully understand. You are
> defining "perspective" as "depth of field", but no one else is.
>
> --
> Jeremy | jeremy@exit109.com

You are getting closer Jeremy but a long way to go yet.
I'll give you 9 points for at least trying to comprehend.

Doug
!