Giccin wrote in post #12021172
I'm not sure if this was cleared or not but..
Does the IS on the 24-105 have a significant impact on the photographer if he or she is not using a tripod?
When you take a picture, the general consensus is that your shutter speed for a sharp photo should be 1/(focal length). So, if you're shooting at 200mm, your shutter speed should be 1/200 to have a sharp picture. So, when you're shooting at 24mm on the 24-70 or 24-105, you should be using 1/24th of a second. The IS on the 24-105 is a 3-stop IS system. That means, instead of using 1/24th of a second (or 1/30th because it's the closest normal shutter speed), you could use 3 stops slower of a shutter speed to get an equivalently sharp image. So instead of 1/30th of a second, 1/4 of a second could be handheld. Of course this is theoretical, and doesn't necessary translate to real world results. I have played with my 24-105 though and shut the IS off and on and there is a VERY clear difference when you start to get to those borderline handheld shutter speeds. The difference in sharpness is obvious and, I think, worthwhile.
Edit: And based on the other response you got, I may have way over explained this. I apologize if that's the case.