Re: [Leica] RE: Enlarging lenses/ a flat field is better for macro

["Dan Post" <dwpost@email.msn.com>]

Duane is right too- Edmund Scientific is selling Schneider enlarging lenses
for Industrial and Robotic video imaging! Maybe the 'economy of scale'
factor will kick in- if they make more for other reasons, the price will
come down, and we can take advantage of lower prices! Now- if they'd only
sell the Focotars on a large scale!
dwpost@msn.com
- -----Original Message-----
From: BIRKEY, DUANE <dbirkey@hcjb.org.ec>
To: leica-users@mejac.palo-alto.ca.us <leica-users@mejac.palo-alto.ca.us>
Date: Tuesday, January 27, 1998 12:15 PM
Subject: [Leica] RE: Enlarging lenses/ a flat field is better for macro

>I respect Jim Brick, but I beg to differ that enlarging lenses make
>poor camera lenses especially for macro work.  The reason camera lenses
>make poor enlarging lenses is because of curvature of field..  The
>reason many Leicas lenses (some of the non ASPH Summiluxes) would make
>poor enlarging lenses is that they have extremely high curvature of
>field which is incidently is one of the reasons cited as to why they
>don't do well in Popular Photography tests.  The reason many normal
>lenses work better reversed for extreme close-ups is due to too much
>field of curvature and a few other reasons I'm sure.  (I'll defer to
>Erwin.)
>
>Ron Wisner will tell you that you want your lens to have the flattest
>field of curvature possible and to imply that you need curvature of
>field to render 3-Dimensional objects sharply is simply a bunch of
>bunk.  Think about it,  When we focus on something, the zone of focus
>is relatively flat as objects behind and in front of the subject are
>out of focus anyhow.  Whether I'm  taking pictures of flat objects or
>not is really irrelevant.  Do you want to use a camera lens that can't
>render a wall 10 ft. away sharp from corner to corner? I certainly
>don't.
>
>Curvature of field is only one the things that designers are looking at
>while designing lenses,  they will often fudge on a bit on that to have
>better corrections in other areas of the design.  A lot of large format
>landscape photographers use "process"  lenses (I.E. G-Claron and Nikkor
>M) for photography of 3-dimensional objects and they work great as long
>as you use them stopped down to a reasonable aperture.
>
>I believe that the using the Rodenstock APO enlarging lens Christoph
>has will give him superior results than almost any lens he could
>choose.  High quality APO enlarging lenses will run circles around any
>normal lens and most macro lenses when used for close-ups.  I can not
>answer whether this combination is as good or better than the 100 F/2.8
>APO R for macro work.  Someone else who owns suitable equipment for
>testing will have to answer that.  I can say with no hesitation that he
>won't be disappointed by the results.
>
>Duane Birkey
>HCJB World Radio
>Quito Ecuador
>
>
>
>
>
>>JB wrote:
>
>>> Just as camera lenses make poor enlarging lenses, enlarging lenses
>make
>>> poor camera lenses UNLESS you are photographing a flat field. Flat
>to flat.
>>> Like in an enlarger. Flat neg to flat paper. Use the enlarging lens
>to copy
>>> photographs, artwork, documents, etc. It's much better than a camera
>lens
>>> for this purpose. But not for 3-D subjects. Leitz originally used
>camera
>>> lenses on their enlargers. But soon discovered that lenses made for
>flat
>>> field work would be much better. So they designed enlarging lenses
>for that
>>> purpose. As did the rest of the industry. That's why there are
>>> enlarger/copy lenses, and there are camera lenses.
>>>
>>> I'm not saying that the resulting photographs will be horrible or
>even
>>> unusable. They will indeed be usable and possibly quite good. I'm
>saying
>>> that lenses were designed for a specific purpose and work BEST when
>used
>>> for that purpose.
>>>
>>> Jim
>
>
>>I may be a bit late on this one, I'm afraid, but could somebody be a
>>bit more specific on the disadvantageous of using an enlarger lens
>>when used on a SLR?
>>I am planning to do so with a Rodenstock APO 105/4 on a tilt
>>adapter for macro photography. I do see two disadvantages:
>>1) I have to set aperture manually (not a big deal IMO)
>>2) The lens does not decrease its focal length as some true macro
>>lenses do. Therefore I will lose more light working at close
>>distances (and larger extensions) according to the square distance
>>law.
>
>>Any other disadvantages?
>
>>Thanks
>>Christoph Held
>>held@biologie.uni-bielefeld.de
>
>