> Which of the many 50mm lenses, made by Pentax, is considered to be > the best in terms of image quality?
And then, if we throw 50mm macro lenses into the mix, there may be additional thoughts (on this 50mm "sub-category"). My personal opinions: The F 50/2.8 (and I understand the FA is the same) is just a wee bit better than the A 50/2.8 (which, in turn, is better than the M 50/4) in both resolution and contrast. But, that's for image quality alone. If I include other factors, the A 50/2.8 (which is a real joy to use) easily wins, hands down, for 50mm macros. Fred