Hand held shutter speed that is.
I have a 24-105 and have been thinking about the 24-70. I've been doing some test with my lens comparing IS vs non-IS performance. In 3-4 shot bursts, I'm surprised how good some of the non-IS shots look. Of course there are more acceptable shots with IS than without and the best IS shots are better than the best non-IS shots, but I'm thinking IS might not be as important at 105mm as I had once thought. I tested it as 1/50, 1/25, 1/13, and 1/5.





