pulsar123 wrote in post #15437258
My only experience with telephoto zoom - used 70-200 f4 - seems to be behaving much better: something like -4...-2 using FoCal and halogen lamp. (But seems more like -6...-4 using daylight - needs more testing.)
Do you have any fast primes - what MFA do they need?
My testing has been indoors with both halogen and LED light sources and the light level has been around EV 8 or 9 (I think FoCal documentation says EV 10 somewhere?), so perhaps my setup is not ideal.
I tested an 85/1.8 and FoCal came back with +4 required.
s2kdriver80 wrote in post #15437592
I would also check AFMA variances among different AF points. Enable off-centre AF points in FoCal.
I'm currently using Pro so I don't have this option, but may look at it further down the road. Looking at the description on Reikan's page I can just imagine the can of worms it might open!
hollis_f wrote in post #15438313
Did you just think it was a big variance, or did you actually check to see how big a difference there was?
If you have FoCal Pro then you can look at the graphs to see how much difference there is at different MFA values. My experience is that, most of the time, there's very little difference over a wide range of values at the top of the graph.
I'd be surprised if there was a large difference between -10 and -6 on the wide end and between -6 and -2 on the long end - certainly nothing big enough without pixel-peeking at 100%. So it's very likely that a value of -6 will be perfectly good.
Being an MFA rookie, I made an uneducated assumption, hence this thread. I want to get a feel of what is "normal" zoom lens variance and ultimately not be OCD about the whole process.
The suggestion to MFA for a compromise between wide and long ends sounds logical to me. How has that worked out in practice? I have read somewhere that you should MFA based on the long end since DOF increases when shooting wider and would then mask any focusing inaccuracy.