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"film" and "digital" lenses

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Anonymous
May 30, 2005 1:08:22 AM

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

Someone said in alt.photography that "film" lenses are designed to focus the
different color wavelengths differently to make up for the layered emulsion
in film. That sounds like non-sense to me.

Opinions?

--
Mark

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

More about : film digital lenses

Anonymous
May 30, 2005 1:08:23 AM

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

Mr. Mark wrote:

> Someone said in alt.photography that "film" lenses are designed to
> focus the different color wavelengths differently to make up
> for the layered emulsion in film. That sounds like non-sense to me.

I believe you're right.

The 'layers' of film emulsions are so thin as to escape correction in
the optics. Film thickness variance, optics variances, film transport
variances and so on, combined, are huge compared to the thin-ness of the
film emulsion.

Further, the film companies have differing emulsion build up designs,
including Fuji "4th layer" in some negative films. I never heard of
needing special lenses for that...

>
>
> Opinions?

The only 'issue' I know of, and don't pay much attention to, is whether
UV filters are necessary anymore. A flat piece of optical glass as a
sacrificial filter (or better: none at all) is all that is needed. This
does apply to CCD (lower UV sensitivity than film), I don't know about CMOS.

OTOH I've seen another claim that lack of UV filtering may lead to
'blooming' when photosites are close to saturation. (May apply to CMOS
and not CCD, I don't know).

All the lenses, unless designed to filter specifically, pass a range of
light far larger than the visible range we're interested in but are
centered in the visual spectrum where focus on the film plane is
concerned. The sensors have filtering (to greater or lesser degrees) in
their covers to block IR and possibly UV.

Cheers,
Alan.

--
-- r.p.e.35mm user resource: http://www.aliasimages.com/rpe35mmur.htm
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Anonymous
May 30, 2005 1:08:23 AM

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

Mr. Mark wrote:

> Someone said in alt.photography that "film" lenses are designed to focus the
> different color wavelengths differently to make up for the layered emulsion
> in film. That sounds like non-sense to me.
>
> Opinions?



I heard there is a coating on the rear element to prevent reflections
off the sensor for digital lenses though I've not seen any example of
these reflections so I assume it's quite a minor issue.


--
Paul Furman
http://www.edgehill.net/1
san francisco native plants
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Anonymous
May 30, 2005 2:51:03 AM

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

"Alan Browne" <alan.browne@FreelunchVideotron.ca> wrote in message
news:D 7dd35$l0a$1@inews.gazeta.pl...
> Mr. Mark wrote:
>
> > Someone said in alt.photography that "film" lenses are designed to
> > focus the different color wavelengths differently to make up
> > for the layered emulsion in film. That sounds like non-sense to me.
>
> I believe you're right.
>
> The 'layers' of film emulsions are so thin as to escape correction in the
> optics. Film thickness variance, optics variances, film transport
> variances and so on, combined, are huge compared to the thin-ness of the
> film emulsion.
>
> Further, the film companies have differing emulsion build up designs,
> including Fuji "4th layer" in some negative films. I never heard of
> needing special lenses for that...

Or special lenses for black and white...
May 30, 2005 3:38:06 AM

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

Mr. Mark wrote:

> Someone said in alt.photography that "film" lenses are designed to focus
> the different color wavelengths differently to make up for the layered
> emulsion in film.

Thats BS..

--

Stacey
May 30, 2005 4:25:53 AM

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

Mr. Mark wrote:
>
> Someone said in alt.photography that "film" lenses are designed to focus
> the different color wavelengths differently to make up for the layered
> emulsion in film.
>
Like George Preddy claiming Lateral Chromatic Aberration was a Sigma
feature...
Anonymous
May 30, 2005 11:52:28 AM

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

Martin Francis wrote:

>>Further, the film companies have differing emulsion build up designs,
>>including Fuji "4th layer" in some negative films. I never heard of
>>needing special lenses for that...
>
>
> Or special lenses for black and white...

Good point.

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: Remove FreeLunch.
Anonymous
May 30, 2005 1:54:33 PM

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

Paul Furman wrote:

> Mr. Mark wrote:
>
>> Someone said in alt.photography that "film" lenses are designed to
>> focus the
>> different color wavelengths differently to make up for the layered
>> emulsion
>> in film. That sounds like non-sense to me.
>>
>> Opinions?
>
>
>
>
> I heard there is a coating on the rear element to prevent reflections
> off the sensor for digital lenses though I've not seen any example of
> these reflections so I assume it's quite a minor issue.

So minor that DSLR's cannot do OTF TTL metering. Any need for coatings
to help in this regard sounds like the cry of the marketeers.

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: Remove FreeLunch.
Anonymous
May 30, 2005 7:19:40 PM

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

In article <d7eupn$18a$2@inews.gazeta.pl>,
Alan Browne <alan.browne@FreelunchVideotron.ca> wrote:
>Martin Francis wrote:
>
>>>Further, the film companies have differing emulsion build up designs,
>>>including Fuji "4th layer" in some negative films. I never heard of
>>>needing special lenses for that...
>>
>>
>> Or special lenses for black and white...
>
>Good point.

I seem to remember a special three-layer B&W film from perhaps
the late 1960s or early 1970s. I have never used it, but I read the
reviews of it with great interest.

Each layer was a different ISO, and by selective color
filtration in the enlarger, you could select the layer which had what
you wanted.

IIRC, the review showed a shot of a clear glass light bulb, in
operation, and from one layer, you could get the image of the glass
envelope (with the filament vastly over-exposed), while from another,
you could get an image which showed detail of the glowing filament.

But, granted, this is an extreme example, and as far as I know,
the film had a very short life in the market -- just too special
purpose. :-)

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 ---
Anonymous
May 30, 2005 8:49:50 PM

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

DoN. Nichols wrote:


>
> I seem to remember a special three-layer B&W film from perhaps
> the late 1960s or early 1970s. I have never used it, but I read the
> reviews of it with great interest.
>
> Each layer was a different ISO, and by selective color
> filtration in the enlarger, you could select the layer which had what
> you wanted.
>
> IIRC, the review showed a shot of a clear glass light bulb, in
> operation, and from one layer, you could get the image of the glass
> envelope (with the filament vastly over-exposed), while from another,
> you could get an image which showed detail of the glowing filament.
>
> But, granted, this is an extreme example, and as far as I know,
> the film had a very short life in the market -- just too special
> purpose. :-)

I love trivia like that. People tried to achieve new things in smart
ways. Like you say, a little too special for a market that demands fast
access to the film and reasonable turnaround. That film seems to have
required too much post processing to be any fun to use.

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: Remove FreeLunch.
Anonymous
May 30, 2005 9:06:17 PM

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

> > Further, the film companies have differing emulsion build up designs,
> > including Fuji "4th layer" in some negative films. I never heard of
> > needing special lenses for that...
>
> Or special lenses for black and white...

That was the first thing I considered. I even asked the poster about that
and several folks have replied that he's full of $#@!, but he has apparently
disappeared.

--
Mark

Photos, Ideas & Opinions
http://www.marklauter.com
Anonymous
May 30, 2005 9:07:35 PM

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

> I heard there is a coating on the rear element to prevent reflections
> off the sensor for digital lenses though I've not seen any example of
> these reflections so I assume it's quite a minor issue.

Wouldn't film do the same thing? It's shiny plasticy stuff after all.

--
Mark

Photos, Ideas & Opinions
http://www.marklauter.com
Anonymous
May 30, 2005 9:07:36 PM

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

In article <rLHme.83424$w15.16951@tornado.tampabay.rr.com>,
Mr. Mark <e.cartman@southpark.com> wrote:
>> I heard there is a coating on the rear element to prevent reflections
>> off the sensor for digital lenses though I've not seen any example of
>> these reflections so I assume it's quite a minor issue.
>
>Wouldn't film do the same thing? It's shiny plasticy stuff after all.

The film itself is (that is the plastic backing material), but
the emulsion which faces the lens is typically a matte gray prior to
development. Thus it is not capable of specular (mirror-like)
reflections.

There is also typically a darker coating on the back of the film
to reduce reflections from particularly bright highlights which can
punch through the emulsion and reach the back. This is dissolved in the
processing of the film.

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 ---
Anonymous
May 30, 2005 10:57:22 PM

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

On Mon, 30 May 2005 17:07:35 GMT, Mr. Mark <e.cartman@southpark.com> wrote:
>> I heard there is a coating on the rear element to prevent reflections
>> off the sensor for digital lenses though I've not seen any example of
>> these reflections so I assume it's quite a minor issue.
>
> Wouldn't film do the same thing? It's shiny plasticy stuff after all.

Not as shiny.

BTW, you wouldn't necessarily see the reflections, they can manifest
as a general lack of contrast.

--
Ben Rosengart (212) 741-4400 x215
Sometimes it only makes sense to focus our attention on those
questions that are equal parts trivial and intriguing.
--Josh Micah Marshall
Anonymous
May 30, 2005 10:57:45 PM

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

On Mon, 30 May 2005 17:07:35 GMT, Mr. Mark <e.cartman@southpark.com> wrote:
>> I heard there is a coating on the rear element to prevent reflections
>> off the sensor for digital lenses though I've not seen any example of
>> these reflections so I assume it's quite a minor issue.
>
> Wouldn't film do the same thing? It's shiny plasticy stuff after all.

Not as shiny.

BTW, you wouldn't necessarily see the reflections, they can manifest
as a general lack of contrast.

--
Ben Rosengart (212) 741-4400 x215
Sometimes it only makes sense to focus our attention on those
questions that are equal parts trivial and intriguing.
--Josh Micah Marshall
Anonymous
May 31, 2005 2:46:00 AM

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

On Mon, 30 May 2005 16:49:50 -0400, Alan Browne
<alan.browne@FreelunchVideotron.ca> wrote:

>DoN. Nichols wrote:
>
>
>>
>> I seem to remember a special three-layer B&W film from perhaps
>> the late 1960s or early 1970s. I have never used it, but I read the
>> reviews of it with great interest.
>>
>> Each layer was a different ISO, and by selective color
>> filtration in the enlarger, you could select the layer which had what
>> you wanted.
>>
>> IIRC, the review showed a shot of a clear glass light bulb, in
>> operation, and from one layer, you could get the image of the glass
>> envelope (with the filament vastly over-exposed), while from another,
>> you could get an image which showed detail of the glowing filament.
>>
>> But, granted, this is an extreme example, and as far as I know,
>> the film had a very short life in the market -- just too special
>> purpose. :-)
>
>I love trivia like that. People tried to achieve new things in smart
>ways. Like you say, a little too special for a market that demands fast
>access to the film and reasonable turnaround. That film seems to have
>required too much post processing to be any fun to use.
>
>Cheers,
>Alan.

Ilford XP1 = garbage. It had supressed grain but was so finicky when
it came to contrast it wasn't worth using.
-Rich
May 31, 2005 11:45:45 AM

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

>From my personal evaluation of film lenses on digital ...
.... it seems to be a generational thing. Some particular coatings that
have a desired effect on film have a negative effect with digital.
My Pentax SMC 30/2.8 is outstanding for both film and digital, as are
the newer Pentax-F 50/1.7 and Pentax-FA 50/1.4. But the "A" series
lenses (Pentax-A 50/1.7, 35/2, and 100/2.8 [non-macro]) are only
average lenses. There's some color fringing toward the edges unless I
correct the white balance.
So the answer is yes and no. Some film lenses don't perform well with
digital. But some do. It's not necessarily because they were film
lenses. There is a correlation, but it is not a causal relationship.

Conversely, digital lenses should always perform well with film,
especially with traditional b&w with its single-layer emulsion. In the
Pentax world, the new Pentax-DA 40/2.8 is a tempting new offering,
well-suited for both fomats. (But I'm not quite ready to shell out
$399 for it.) Yes, it's another pancake. And a pretty one at that.

Collin
KC8TKA
May 31, 2005 12:16:45 PM

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

True. Some of Pentax' newer releases are for both (DA series, iirc)
and others are only for digital.

Collin
Anonymous
May 31, 2005 6:40:36 PM

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

"Ben Rosengart" <br+rpdss@panix.com> wrote in message

> BTW, you wouldn't necessarily see the reflections, they can manifest
> as a general lack of contrast.

I hadn't considered that. Thanks.


--
Mark

Photos, Ideas & Opinions
http://www.marklauter.com
Anonymous
May 31, 2005 6:48:32 PM

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

On 31 May 2005 07:45:45 -0700, Cheesehead <dplotusnotes@yahoo.com> wrote:
>
> Conversely, digital lenses should always perform well with film,

Well, watch out for "digital" lenses that project a smaller image circle.
You'll get *severe* vignetting on a film camera.

--
Ben Rosengart (212) 741-4400 x215
Sometimes it only makes sense to focus our attention on those
questions that are equal parts trivial and intriguing.
--Josh Micah Marshall
!