I got a 10stop ND and i know the AF doesnt work once you put it on.
For typical daylight/overcast condition,
what is the maximum # of Stop for ND filter, and the camera AF still have enough light to work ?
Using D90/D7100 if it matters.
Looking to get a bigger Kenko/Hoya ProND64/100/200/500.
(not considering the variable ND, there isnt one that is both good + affordable)