Quote Originally Posted by clemmb View Post
4 stops @ 200mm. I wonder what it is with 2x so you are @400mm.
Low light is important for hand holding but also for subject movement. IS will not help with subject movement. Using a 1.4x giving an f4 @280mm will probably be better than 300mm @ f5.6.
Do you think it drops progressively with length?
Actually I have never seen an article or a discussion if a tele convertor affects IS.

I didn't know we were talking IS for subject movement, just low light situations.