Quote Originally Posted by Ehcalum


shooting a 70-200 2.8 at 1/100 is doable for me. The "3 stop gain" is pure marketing, similar to saying you get extra reach with a crop factor camera. You don't magically receive 3 stops of expouser.
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It's not all marketing. You can easilytest the "3 stop gain" claim. Find out how slow of a shutter speed you can sucessfully hand-hold a lens and see if you can replicate that same shot shooting with shutterspeeds 8X's slower with the helpof IS. I think the full 3 stops is probably best case but I can usually bank on an extra 2 stops of hand-holdability. That would mean that you could hand-hold your 70-200 f.8 at 1/25! Sure, if you're photographing a soccer game 1/25 won't do much for you but if you're shooting a landscape, a flower, etc it's pretty sweet.