DOF in viewfinder different from captured image!

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

This is weird.. I have a Nikon D70s.. just picked it up the other day..
my first DSLR (after using a Nikon FE-2).. so i put on my 50mm 1.4 AiS
lens and look through the viewfinder.. and things pretty much look
focused.. like as if i'm at f4 or f5.6.. i click the shutter (aperture
set at f1.4) and the captured image has shallow depth of field - as
expected at f1.4... but how come what i see through the viewfinder is
not the same?!!!!

Same story with my 35-135mm f3.5-3.5 AiS lens.. when i put it on.. and
take a picture at 3.5, it's different than what i'm seeing in the
viewfinder... the viewfinder image is again more like f5.6 ...

what's up with that??

Thanks for any insight.

p.s. i don't seem to have this problem with the AF-S 17-80mm DX (kit)
lens.. but then again.. its maximum aperture is already at f4.5..

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

No I don't think you get it.. the viewfinder is supposed to show me DOF
equivalent to f1.4 if my attached lens is 50mm f1.4!.. likewise, if my
other lens stops down to f3.5 then that's what i should see through the
viewfinder.. regardless of what actual aperture i end up shooting at..

but what i'm saying is, that even with my 50mm f1.4 lens, what i'm
seenig through the viewfinder is something more like f5.6.. the f5.6
should only end up on film (or ccd) but NOT in the viewfinder UNLESS i
engaged the DOF preview button...

I hope i'm clear....

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

Hussam wrote:
> No I don't think you get it.. the viewfinder is supposed to show me
> DOF equivalent to f1.4 if my attached lens is 50mm f1.4!.. likewise,
> if my other lens stops down to f3.5 then that's what i should see
> through the viewfinder.. regardless of what actual aperture i end up
> shooting at..
>
> but what i'm saying is, that even with my 50mm f1.4 lens, what i'm
> seenig through the viewfinder is something more like f5.6.. the f5.6
> should only end up on film (or ccd) but NOT in the viewfinder UNLESS
> i
> engaged the DOF preview button...
>
> I hope i'm clear....

Take the picture, shrink it to the relative size of your viewfinder
and judge the difference in focus between the in-DOF and out-of-DOF
features. Could it be the scale of the viewfinder doesn't allow useful
discriminations on wide-open, low-F views?

--
Frank ess

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

On 25 Sep 2005 14:32:50 -0700, "wilt" <wiltw@aol.com> wrote:

>Not intimately familiar with the D70, but a long time ago with
>twin-lens reflexes point and shoots, the aerial image thru the aiming
>lens was nice and bright and easy to see. Just point and shoot and
>don't worry about focus. Everything was sharp in these finders!
>Then SLRs came about, and groundglass was employed so that the entire
>screen could be focused, but not with enough precision, so focusing
>aids like split screen and microprism were added to improve focus
>acuity. But with the precision can darkening of the central focusing
>aide. Then manufacturers introduced exchangeable focusing screens, so
>that you could have enough focus precision for a long focal length lens
>without the screen darkening horribly.

Never has this problem with my early Nikons and later the Contarex
with it's fresnel focusing screen with a microprism ring around the
split prism.


>Now comes the autofocus SLR...the manufacturers begin with very bright
>focusing screens that are near useless for manual focus, but when
>photographers mount manual focus lenses they suddenly want some
>focusing precision, but not all the SLRs are optimized for that...they
>still use nice bright finders and focusing screens, but somewhat like
>the old aerial images fo the TLR point and shoot...so they show a lot
>of stuff in focus because the screens are designed to be bright, and
>that is counter to showing things sharp vs. somewhat unfocused for DOF
>evaluation.

So? You just put in a focusing screen that supports good manual
focus.

Canon has several for the 1 bodies and there are third party solutions
for the low end Canons.

The real problem with most DSLR's is found in the small sensor and the
lack of a true pentaprism.
*********************************************************

"I have been a witness, and these pictures are
my testimony. The events I have recorded should
not be forgotten and must not be repeated."

-James Nachtwey-
http://www.jamesnachtwey.com/

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

In article <1127678389.120858.193500@o13g2000cwo.googlegroups.com>,
"Hussam" <hktaha@gmail.com> wrote:

> No I don't think you get it.. the viewfinder is supposed to show me DOF
> equivalent to f1.4 if my attached lens is 50mm f1.4!.. likewise, if my
> other lens stops down to f3.5 then that's what i should see through the
> viewfinder.. regardless of what actual aperture i end up shooting at..
>
> but what i'm saying is, that even with my 50mm f1.4 lens, what i'm
> seenig through the viewfinder is something more like f5.6.. the f5.6
> should only end up on film (or ccd) but NOT in the viewfinder UNLESS i
> engaged the DOF preview button...
>
> I hope i'm clear....

You're clear but you're wrong and confused. Please don't snip so much
of the post in the future.

You said:

> This is weird.. I have a Nikon D70s.. just picked it up the other day..
> my first DSLR (after using a Nikon FE-2).. so i put on my 50mm 1.4 AiS
> lens and look through the viewfinder.. and things pretty much look
> focused.. like as if i'm at f4 or f5.6.. i click the shutter (aperture
> set at f1.4) and the captured image has shallow depth of field - as
> expected at f1.4... but how come what i see through the viewfinder is
> not the same?!!!!

You wanted to know why what you saw in the view finder ("like as if i'm
at f4 or f5.6" ) does not look like the finished image (" shallow depth
of field as expected at f1.4 but how come what i see through the
viewfinder is not the same?!" ).

> Same story with my 35-135mm f3.5-3.5 AiS lens.. when i put it on.. and
> take a picture at 3.5, it's different than what i'm seeing in the
> viewfinder... the viewfinder image is again more like f5.6

FIrst I want to ask you how you can judge DOF that precisely.

You have not said what distance the object you are focusing on is, which
also has an effect on DOF.

Oh, and don't go by the view finder. Tell us about the digital image.

But you communicated it all poorly. Maybe try again. Be very specific
with everything, limit the variables.

--

Photographs by Christian Bonanno
http://christianbonanno.com/

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

According to John A. Stovall <johnastovall@earthlink.net>:
> On 25 Sep 2005 14:32:50 -0700, "wilt" <wiltw@aol.com> wrote:
>
> >Not intimately familiar with the D70, but a long time ago with
> >twin-lens reflexes point and shoots, the aerial image thru the aiming
> >lens was nice and bright and easy to see. Just point and shoot and
> >don't worry about focus. Everything was sharp in these finders!
> >Then SLRs came about, and groundglass was employed so that the entire
> >screen could be focused, but not with enough precision, so focusing
> >aids like split screen and microprism were added to improve focus
> >acuity. But with the precision can darkening of the central focusing
> >aide. Then manufacturers introduced exchangeable focusing screens, so
> >that you could have enough focus precision for a long focal length lens
> >without the screen darkening horribly.
>
> Never has this problem with my early Nikons and later the Contarex
> with it's fresnel focusing screen with a microprism ring around the
> split prism.

Of course -- they were designed for *manual* focusing, as
autofocus did not exist at the time. They also had changeable focusing
screens because a microprism and split image which worked well with
wide angle lenses would not work so well with a telephoto and vice
versa -- as well as allowing you to select focusing screens better for a
given set of conditions.

IIRC, the screens for the Nikon F where this mattered came in
four different focal length ranges, to adapt to your lens focal length
range.

For critical focus with really long lenses, or for working
through a microscope, there was a plain ground glass screen (which would
work equally dimly with all focal lengths) with a clear center spot with
a fine '+' in the center. If you moved your head from side to side
behind the viewfinder (assuming a rigidly mounted camera, of course), if
the center area were truly in focus, you would see no relative motion
between the '+' and the image. However, the more out of focus it was,
the more relative motions was visible. This would work when any of the
split image or microprism screens would not.

> >Now comes the autofocus SLR...the manufacturers begin with very bright
> >focusing screens that are near useless for manual focus, but when
> >photographers mount manual focus lenses they suddenly want some
> >focusing precision, but not all the SLRs are optimized for that...they
> >still use nice bright finders and focusing screens, but somewhat like
> >the old aerial images fo the TLR point and shoot...so they show a lot
> >of stuff in focus because the screens are designed to be bright, and
> >that is counter to showing things sharp vs. somewhat unfocused for DOF
> >evaluation.
>
> So? You just put in a focusing screen that supports good manual
> focus.

Easy to say. However, the D70 (and presumably the D70s) does
not have interchangeable focusing screens -- at least in part because
the autofocus depends on special microprisms oriented to concentrate on
the autofocus sensors, not on the user's eye. Also, the focusing screen
has a lot of active electro-optical displays on it, such things as the
autofocus zone indicators and the grid which can be switched on and off.
That means a lot of interconnections, which could make problems with
contact quality every time you changed focusing screens.

> Canon has several for the 1 bodies and there are third party solutions
> for the low end Canons.

Is this true for the Cannon DSLRs? If so, does the Cannon DSLR
also have active displays on the focusing screen as the Nikon does?

Enjoy,
DoN.

--
Email: <dnichols@d-and-d.com> | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

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

On 25 Sep 2005 10:32:13 -0700, "Hussam" <hktaha@gmail.com> wrote:

>This is weird.. I have a Nikon D70s.. just picked it up the other day..
>my first DSLR (after using a Nikon FE-2).. so i put on my 50mm 1.4 AiS
>lens and look through the viewfinder.. and things pretty much look
>focused.. like as if i'm at f4 or f5.6.. i click the shutter (aperture
>set at f1.4) and the captured image has shallow depth of field - as
>expected at f1.4... but how come what i see through the viewfinder is
>not the same?!!!!
>
>Same story with my 35-135mm f3.5-3.5 AiS lens.. when i put it on.. and
>take a picture at 3.5, it's different than what i'm seeing in the
>viewfinder... the viewfinder image is again more like f5.6 ...
>
>what's up with that??
>
>Thanks for any insight.
>
>p.s. i don't seem to have this problem with the AF-S 17-80mm DX (kit)
>lens.. but then again.. its maximum aperture is already at f4.5..

I may not be much help here, I use Canon so don't have much specific
experience with Nikon. Having said that, most Canon equipment has an
"aperture preview" button. In other words you set your aperture but
you will see nothing happen in the viewfinder. What's happening is
that the aperture is staying pretty open to allow maximum light in so
that you can see to focus. If you really want to see what effect the
aperture is going to have you need to press the "aperture preview"
button (to really check DOF and so forth).

I don't know if Nikon does it the same way.

Drifter
"I've been here, I've been there..."

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

On 26 Sep 2005 02:13:26 GMT, dnichols@d-and-d.com (DoN. Nichols)
wrote:

snipped
> Is this true for the Cannon DSLRs? If so, does the Cannon DSLR
>also have active displays on the focusing screen as the Nikon does?

http://www.dpreview.com/news/0508/ [...] dmkiin.asp

The camera’s focusing screens are interchangeable; an optional new
“Super Precision Matte” Ec-S focusing screen enables easier manual
focusing with fast lenses.

http://www.bhphotovideo.com/bnh/co [...] Q=&ci=4662

If you want to buy some.


*********************************************************

"I have been a witness, and these pictures are
my testimony. The events I have recorded should
not be forgotten and must not be repeated."

-James Nachtwey-
http://www.jamesnachtwey.com/

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

The aperture is working fine... the viewfinder is nice and bright.. the
lens is NOT stopped down... but looking thru the viewfinder the depth
of field is "deeper" than captured image even though i'm shooting at
f1.4 (or f3.5 in the case of the other lens).....

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

HI.. thanks for your thorough reply... I'm comparing the image in the
viewfinder to the image on the lcd ... it's not that hard to tell the
difference between an f1.4 and an f5.6 image.. i'm focusing at
something that's about 2 meters away and looking at a background that
is about 4-5 meters away.... you can tell the difference.

Also, with non-CPU lenses (as is the case with my manual focus 50mm and
35-135mm lenses), you MUST use Manual mode on the D70s... so i wasn't
on Auto.

I THINK the explanation is the diopter adjustment messing with the
image in the viewfinder.. making it sharper than what it really is..?
i'll check.

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

Hussam wrote:

> I'm not wrong.. but confused yes... that's why i posted my question.
>
> As to how i can judge DOF that precisely... it's not that hard to tell
> the difference between f1.4 and f5.6.. the difference is pretty big!
> You don't need super vision for that.
>
> Sorry for not specifying what distance i was focusing at.. didn't think
> it made a difference...i was focusing at 2 meters with the background
> being at 4-5 meters.
>
> What do you mean don't go by the viewfinder..i'm using an SLR!!! what
> else am i supposed to go by?!!!
>

The human eye can focus & see depth where the lens, f/stop & sensor
combination cannot capture it. Your brain is actually interpreting some
of the out of focus image and bringing it into focus for you.

Literally you SEE f/5.6 even when the viewfinder has f/1.4 DOF.

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

"Hussam" <hktaha@gmail.com> wrote in message
news:1127756844.621888.77780@z14g2000cwz.googlegroups.com...

> The aperture is working fine... the viewfinder is nice and bright.. the
> lens is NOT stopped down... but looking thru the viewfinder the depth
> of field is "deeper" than captured image even though i'm shooting at
> f1.4 (or f3.5 in the case of the other lens).....

What makes you think so?

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

Not sure but I read somewhere that the viewfinder does not
use a 'ground' glas but microlenses. These are optimised
for 2.8 lensens. So the suggested effect would be that all
lensens with a larger aperature show as a 2.8 lens.

You should be able to confirm this. Use the Dof button
on 1.4, 2, 2.8, 4 etc. You should benoticing no or hardly
any difference between the settings up to 2.8 and then
there should be severe dimming and more dof above
2.8.

This does not explain your problem with the f3.5 lens.

Other factors come into play as wel, your eyes in
combination with your brain can compensate a lot
if the image is not totaly sharp. I know that my brain
(especcially if I squint) can make a picture apear
sharper than it actually is.

Lot's of people remarked that there are no focussing
aids in the D70. I think the whole 'ground' glas can
be used as a focusing aid because of the microlenses.
But yes the size of the image is a lot smaller than that
of a 35 mm slr.

Please report if the suggestion I give in the second
alinea is confirmed by trying. (I do not posses a 1.4
lens so can not try this myself).

ben brugman


"Hussam" <hktaha@gmail.com> schreef in bericht news:1127669533.119796.156930@z14g2000cwz.googlegroups.com...
> This is weird.. I have a Nikon D70s.. just picked it up the other day..
> my first DSLR (after using a Nikon FE-2).. so i put on my 50mm 1.4 AiS
> lens and look through the viewfinder.. and things pretty much look
> focused.. like as if i'm at f4 or f5.6.. i click the shutter (aperture
> set at f1.4) and the captured image has shallow depth of field - as
> expected at f1.4... but how come what i see through the viewfinder is
> not the same?!!!!
>
> Same story with my 35-135mm f3.5-3.5 AiS lens.. when i put it on.. and
> take a picture at 3.5, it's different than what i'm seeing in the
> viewfinder... the viewfinder image is again more like f5.6 ...
>
> what's up with that??
>
> Thanks for any insight.
>
> p.s. i don't seem to have this problem with the AF-S 17-80mm DX (kit)
> lens.. but then again.. its maximum aperture is already at f4.5..
>

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

"no_name" <no_name@no.where.invalid> wrote in message
news:yZGZe.71788$SL.1480957@twister.southeast.rr.com...
> Hussam wrote:
>
> > This is weird.. I have a Nikon D70s.. just picked it up the other day..
> > my first DSLR (after using a Nikon FE-2).. so i put on my 50mm 1.4 AiS
> > lens and look through the viewfinder.. and things pretty much look
> > focused.. like as if i'm at f4 or f5.6.. i click the shutter (aperture
> > set at f1.4) and the captured image has shallow depth of field - as
> > expected at f1.4... but how come what i see through the viewfinder is
> > not the same?!!!!
>
> The brain provides depth of field the camera lens cannot.

"Hussam" <hktaha@gmail.com> wrote in message
news:1127756933.915809.306330@o13g2000cwo.googlegroups.com...
> that's deep...

Deeper than your perceived depth of field. <g>

--
Mark

Photos, Ideas & Opinions
http://www.marklauter.com

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

Beach Bum wrote:
> "Hussam" <hktaha@gmail.com> wrote in message
> news:1127756844.621888.77780@z14g2000cwz.googlegroups.com...
>
>>The aperture is working fine... the viewfinder is nice and bright.. the
>>lens is NOT stopped down... but looking thru the viewfinder the depth
>>of field is "deeper" than captured image even though i'm shooting at
>>f1.4 (or f3.5 in the case of the other lens).....
>
>
> Your eye compensates for focus as well. The printed photo is static - the
> eye can't compenstate for the blur, but the view finder isn't static.


I do think viewfiner is static. You can see where the focus is. try to
focus to something close and then far and you can see the DoF at work
right on your viewfinder! However, you do need to concentrate because a
viewfinder is many times smaller than if you look at the picture on your
screen at 1:1 ratio. And the depth of field at f/1.4 is so tiny that you
have to move the focus back and forth a bit to track it right.