Greetings,

Regarding the film plane in the Minox (and Yashica Atoron series) 9.5mm cameras:

Back in the early sevenities when I first became interested in subminiature
cameras, I owned both the Minox B and the Yashica Atoron. The B, of course,
had a concave film plane; the Atoron, a flat film plane. I was advised, at
that time, that Minox Labs used negative carriers that were curved to match
the film plane of the camera's taking lens, and that, with a flat film
planed camera like the Atoron, my negatives would exhibit edge sharpness
falloff.

Now, this was twenty-five years ago, back when I was in high school, and my
level of craft and discrimination probably was pretty sorely lacking, but I
never remember observing any real difference in the prints from the two
cameras. (On the other hand, the subtext of that message was: the Yashica
is an inferior camera; get rid of it. Which I did. I was pretty
impressionable.) Shortly thereafter I replaced the Atoron with a BL (hence
my questions regarding the BL the other day); unfortunately, that camera
did not survive a tragic dormitory prank while I was a college freshman.
Don't ask.

In the past few days I've learned from this list that Minox cameras can
have either curved or flat film planes, depending on their lens design. In
retrospect, I really don't see why the film in a negative carrier should be
curved, unless it is to match the curvature of the enlarging lens. Was the
original claim of matching curved film planes just a marketing pant load,
or was there some truth there that I've failed to grasp.

And how on earth would a lab identify what negatives were shot with which
cameras? Did Minox Labs just abandon curved negative carriers when the
later flat planed cameras were introduced?

By the way, does anyone on the list have any recent experience with a
Yashica Atoron or Yashica Atoron Electro? They appear to be somewhat
cheaper on the used market today than the Minox IIIs or B. (Talk about a
less expensive entree into subminiature.) I'd be curious to hear your
comments.

Regards,

M.Phillips
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Date: Tue, 10 Dec 1996 16:32:23 -0800
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From: Joel Moskowitz <mathison@I....>
Subject: Re: Curved v. flat film plane
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The negative of a minox with a curved film plane should show no
distrotion. The curve of the film plane was there to correct lens
distorion (or rather cancel it out). By the same token the enlarger
works the reverse.

Proof:
I have taken pictures with minoxs with both curved and flat planes (B,
C and LX

And printed them on both curved (minox) and flat (bessler) enlarger.

No apparent difference in sharpness no matter how one mixes and matches

Joel

Matthew L. Phillips wrote:
>
> Greetings,
>
> Regarding the film plane in the Minox (and Yashica Atoron series) 9.5mm cameras:
>
> Back in the early sevenities when I first became interested in subminiature
> cameras, I owned both the Minox B and the Yashica Atoron. The B, of course,
> had a concave film plane; the Atoron, a flat film plane. I was advised, at
> that time, that Minox Labs used negative carriers that were curved to match
> the film plane of the camera's taking lens, and that, with a flat film
> planed camera like the Atoron, my negatives would exhibit edge sharpness
> falloff.
>
> Now, this was twenty-five years ago, back when I was in high school, and my
> level of craft and discrimination probably was pretty sorely lacking, but I
> never remember observing any real difference in the prints from the two
> cameras. (On the other hand, the subtext of that message was: the Yashica
> is an inferior camera; get rid of it. Which I did. I was pretty
> impressionable.) Shortly thereafter I replaced the Atoron with a BL (hence
> my questions regarding the BL the other day); unfortunately, that camera
> did not survive a tragic dormitory prank while I was a college freshman.
> Don't ask.
>
> In the past few days I've learned from this list that Minox cameras can
> have either curved or flat film planes, depending on their lens design. In
> retrospect, I really don't see why the film in a negative carrier should be
> curved, unless it is to match the curvature of the enlarging lens. Was the
> original claim of matching curved film planes just a marketing pant load,
> or was there some truth there that I've failed to grasp.
>
> And how on earth would a lab identify what negatives were shot with which
> cameras? Did Minox Labs just abandon curved negative carriers when the
> later flat planed cameras were introduced?
>
> By the way, does anyone on the list have any recent experience with a
> Yashica Atoron or Yashica Atoron Electro? They appear to be somewhat
> cheaper on the used market today than the Minox IIIs or B. (Talk about a
> less expensive entree into subminiature.) I'd be curious to hear your
> comments.
>
> Regards,
>
> M.Phillips
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Date: Tue, 10 Dec 1996 14:34:13 -0800
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From: Arthur Grossman <artg@U....>
Subject: Re: Curved v. flat film plane
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You have hit on something which I brought out some time ago on the www.
Whether or not the negative was shot on a curved film plane can have
nothing to do with how it is enlarged. As you point out, neither the
enlarger nor the person operating it can know how the negative was made.
IF the negative is sharp, and the enlarger is properly set up, the print
will be sharp. If the negative is not sharp, no distortion of it in the
enlarging process can possible make the print sharper than the negative
was. Bob Solomon, of HP Martketing argued with me for several postings
about this, telling me how wrong I was and how Minox themnselves agreed
with his position. I'm afraid that the physics of optics are what they
are and he is wrong and you are right. By the way, I got one very
complimetary note from a physics professor at another university
complimenting me on the simplicity and clarity of my argument, which was
clearly correct.

Arthur Grossman Arthur Grossman
Divisional Dean of Arts Professor of Bassoon
Arts and Sciences School of Music
Box 353765 Box 353450
University of Washington University of Washington
Seattle WA, 98195-3765 Seattle, WA 98195-3450
(206) 543-5340
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Date: Tue, 10 Dec 1996 20:35:19 -0500
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From: peter zimmerman <peterz@E....>
Subject: Re: Curved v. flat film plane
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At 14:34 96/12/10 -0800, you wrote:
>You have hit on something which I brought out some time ago on the www.
>Whether or not the negative was shot on a curved film plane can have
>nothing to do with how it is enlarged. As you point out, neither the
>enlarger nor the person operating it can know how the negative was made.
>IF the negative is sharp, and the enlarger is properly set up, the print
>will be sharp. If the negative is not sharp, no distortion of it in the
>enlarging process can possible make the print sharper than the negative
>was. Bob Solomon, of HP Martketing argued with me for several postings
>about this, telling me how wrong I was and how Minox themnselves agreed
>with his position. I'm afraid that the physics of optics are what they
>are and he is wrong and you are right. By the way, I got one very
>complimetary note from a physics professor at another university
>complimenting me on the simplicity and clarity of my argument, which was
>clearly correct.
>
>
>Arthur Grossman Arthur Grossman
>Divisional Dean of Arts Professor of Bassoon
>Arts and Sciences School of Music
>Box 353765 Box 353450
>University of Washington University of Washington
>Seattle WA, 98195-3765 Seattle, WA 98195-3450
>(206) 543-5340
>
>
This physicist agrees with you, Art. The curved film plane was a 'crutch'
to get rid of the chromatic aberration which was present using 4 elements 1n
a 15mm lens using the glass of the '40s. Minox first tried using a field
flattening lens in 'contact' with the film (the ill-fated Minox II). As far
as I know, the enlarging lenses were always flat field because size was not
an issue, but I could be wrong. My minox enlarger Definitely has a flat
carrier.

pete z
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Date: Tue, 10 Dec 1996 20:55:18 -0500
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From: charles Wong <CharlesW99@A....>
Subject: Re: Curved v. flat film plane
Comments: To: mlphillips@gems.vcu.edu

I think this was just poorly thought out by Minox (rather than intentional
disinformation). It was perpetuated by Cooper's "The Minox Manual". I recall
Modern Photography (or was it Popular) going into details about how the
curved film plane was less expensive than correcting the lens and this was
why large screen movie theaters also had curved screens (doesn't have
anything to do with allowing the audience to see better).
I used an Omega Minox negative carrier with no problems (it is not curved). I
had a Minox Enlarger once and saw no difference (which is why I sold it).
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Date: Tue, 10 Dec 1996 19:44:14 +0100
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From: Don Krehbiel <dkrehbie@S....>
Subject: Re: Curved v. flat film plane
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charles Wong wrote:
>
> I think this was just poorly thought out by Minox

Rolf Kasemeier in his book small minox - BIG PICTURES, states:"One of
the most difficult conditions to achieve in a lens is absolute
edge-to-edge and corner-to-corner sharpness.... This curvature error has
been corrected only partly in the Minox lens. Because of this, other
problems in lens design could be solved much easier and with a greater
degree of success."

Don't forget, they didn't have computers in the '30s!
--
Don
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Date: Tue, 10 Dec 1996 22:21:36 -0500
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Subject: Re: Curved v. flat film plane
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At 19:44 96/12/10 +0100, you wrote:
>charles Wong wrote:
>>
>> I think this was just poorly thought out by Minox
>
>Rolf Kasemeier in his book small minox - BIG PICTURES, states:"One of
>the most difficult conditions to achieve in a lens is absolute
>edge-to-edge and corner-to-corner sharpness.... This curvature error has
>been corrected only partly in the Minox lens. Because of this, other
>problems in lens design could be solved much easier and with a greater
>degree of success."
>
>Don't forget, they didn't have computers in the '30s!
>--
>Don
>
\/\/\/\/\/\/\/\/\/
It wasn't just the lack of computers in the '40s (the Riga didn't have a
curved film surface). It was the lack of high index of refraction, low
color dispersion glass. Seibert could have edge to edge sharpness with
either a flat plane and poor color correction (which didn't matter so much
on a Leica neg because the fringing was smaller compared to the image size),
or he could have sharpness and good color correction and a curved film
surface. Curve the film it was! But by the '70s optical glasses had
improved fantastically so that an equal color correction could be achieved
with four elements in a similar design (asymmetric triplet, four elements in
3 groups, almost exactly like the Tessar and Elmar of old) but with a flat
film surface.
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Date: Wed, 11 Dec 1996 09:47:00 -0500
Reply-To: MARTIN TAI <martin.tai@westonia.com>
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From: MARTIN TAI <martin.tai@W....>
Organization: Westonia Computer Systems of Canada
Subject: Re: Curved v. flat film plane

Arthur Grossman wrote:
-> You have hit on something which I brought out some time ago on the
-> www. Whether or not the negative was shot on a curved film plane can
-> have nothing to do with how it is enlarged. As you point out,
-> neither the enlarger nor the person operating it can know how the
-> negative was made. IF the negative is sharp, and the enlarger is
-> properly set up, the print will be sharp. If the negative is not
-> sharp, no distortion of it in the enlarging process can possible make
-> the print sharper than the negative was. Bob Solomon, of HP
-> Martketing argued with me for several postings

Hi, Authur

You are absolutely right, once a negative left a camera,
it forgot whehter it had was flattend or curved up when exposed.

When the negative goes to enlarging lab, the operator only
need to set up his enlarger according to enlarger instruction.

We know there are two types of enlarging lens,

A) Old Minox enlarger, when required negative carrier to
be curved in order to project sharp image on the easel.

With this type of lens. The negative need to be curved,.
whether the negative was shot on COMPLAN ( curved film plane)
or MINOX lens ( flat film plane ). The negative must be to
be curved, all the same.

B) Flat field enlarger. Modern enlarging lens has a flat field
design, the negative carrier must be flat.

Negative can be taken with COMPLAN lens ( ie curved )
or MINOX lens ( flat film plane), all the same, the negative
must be flat.

Martin Tai
=========================================================================