Originally posted by marcusBMG as a general rule some exposure compensation is needed with PKA mounts. One thing I learnt from
my tests is that the best aperture to chimp from to set that tends to be one stop down, not wide open. Good ones are pretty consistent through middle f's, but you may have an iffy one like the #3 in the test, which showed increasing overexposure.
I was wondering how much the individual PKA mount was affecting the results, so I took the mount from the 23A and now exposure is perfect on the 28mm, using Av, f7.1 and ISO 1600, which are pretty standard settings for a 28mm on a camera that has good high-ISO performance (testing on the K-30).
I am a long way from doing the rigorous testing that you did, Marcus. I have three PKA mounts and three PK mounts so the PKAs stay on the zooms and the PK mounts on the primes in general (primes are easier to get good exposure with the green button). No point putting a PKA on the 500mm mirror lens though.
For a general purpose walkaround, though, I will put the two best PKA on the 28mm and the 35-135mm (40A).
The only Adaptall that I am struggling to get good shots with is the CT-300.