There are formulae to determine the threshold of diffraction that "limits" the resolving power of any given lens - but in this case I won't bother to wrestle with them. An enlarging lens for 35mm ... 50mm focal length or thereabouts - "diffraction limited" at f/4? I don't think so. Enlarging lenses follow the same "laws" as camera lenses .. there is only ONE "set" of laws. Camera lenses are normally equipped with iris diaphrams that only close to the "limit of acceptable diffraction"... typically, *any* 50mm (or so) lens will only stop down to f/16.... close to the limit of diffraction.Originally Posted by Claire Senft
Why is it that so many are so critical of enlarging optics? A camera lens is designed around an "Optimal Aperture" but is certainly useable at a wide variety of others, and the same holds true for enlarging lenses.