Archived posting to the Leica Users Group, 1998/01/27
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]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