[osv]

In this simple test I can clearly demonstrate that the F28 is a better lens, and substantially so. Pixel peeping really shows the differences. No doubt about it, the F28 copy I have is superior to the FA28 counterpart.

i like your approach here, you got the right idea, but i'm skeptical that the fa28 is really that soft.

you didn't mention how you focused these lenses?

if you used af... it needs to be shot with manual focus only; liveview and full magnification for focusing, using fast shutter speeds or a tripod/monopod.

[pathdoc]

Except part of the assessment of an AF lens should be how well the AF works, shouldn't it?

[osv]

my understanding is that af could be different among several copies of the same lens? so the af accuracy of one lens wouldn't necessarily represent how accurately they all autofocused... the af of each lens has to be checked and possibly trimmed on the body that it's going to be used on... that happens with mirrors in cameras.

granted, lenses are like snowflakes, the sharpness of one fa28 certainly isn't going to represent the sharpness of all fa28s, but sharpness problems generally show up as decentering.

here is the takinami rez tests: http://www.takinami.com/yoshihiko/photo/lens_test/pentax_28-30.html

his copy of the fa28 didn't show radical differences at f/2.8, if anything it's stronger on the sides than most of the other 28s... things change as the lenses stop down, tho.

[FotoPete]

Wow so the F28 has the same optical formula as the A28/MII28?

I'm also surprised by the M28/2's numbers!