In a recent thread, the fact emerged that enlarging lenses are optimised for a particular magnification factor. Can anyone advise me what this optimal factor is for the Schneider Componon-S 100mm f5.6 lens?

Many thanks!

-- Ed Hurst (BullMoo@hotmail.com), January 24, 2002

Answers

Go here- http://www.schneideroptics.com/photography/photo_enlarging/componon- s/ then pick the MTF curve you like best. Look at "B prime"- that's the magnification. Obviously the lens performs well over a wide range.

-- Conrad Hoffman (choffman@rpa.net), January 24, 2002.

I didn't see any actual specs on this at the Schneider web site, but I found documentation on some other similar focal length lenses. The Rodenstock Rodagon 105mm f/5.6 is optimized for 6X, the El-Nikkor 105mm f/5.6 is optimized for 5X, and the Fujinon EX 105mm f/5.6 is optimized for 7X. The Schneider is actually 102.3mm, so it's not that far off from the others in terms of focal length.

-- Michael Feldman (mfeldman@qwest.net), January 24, 2002.

No, they don't come right out and give you a simple one number answer, but the MTF curves are given at various magnifications, so you can see this affects performance.

-- Conrad Hoffman (choffman@rpa.net), January 25, 2002.

Thanks for your responses - the web pages you refer to are most interesting. I have to admit that I am not accustomed to interpreting MTF curves, so I am struggling to understand the differences at different magnification factors. From what you have seen of the curves, could you suggest what looks like the best magnification factors?

Many thanks,

Ed

-- Ed Hurst (BullMoo@hotmail.com), January 25, 2002.