Hey guys, I've got a question on ND filters, but first, let me tell you how I'm and why I'm going to use them.
I don't shoot landscapes, or at least don't intend to always shoot landscapes with the ND filter. I shoot portraits with off camera flash, strobist style.
The thing is, on a bright and sunny day, I can never ever get as low as 1/200 ISO100 while shooting wide apertures. I'll always get something like 1/400 while shooting f/2, and this means that the flash will only be present in the upper half of the image, sometimes even less.
When shooting off camera flash, I always aim to underexpose the bg by at least 2 stops and use flash to light my subject properly. Can't do this in the day with fairly small apertures (f/5.6) and definitely not at f/2.
So anyway, I know an ND filter will solve the problem. My question is, how many stops of ND filter should I get, and will I be able to retain AF on them?