> I don't need a tripod either when I > am shooting with am f 2.8 lense and don't have to compromise sharpness > either. IS lenses do inherently have to compromise sharpness due to certain > laws of physics, and there is nothing that can be done about that. Pete, if 300 f2.8 lenses wouldn't be more expensive, heavier and bigger than 300 f/4(.5) IS lenses, you would be right. The point is that, most poeple cannot afford a fast 300mm, and IS system may help reducing the disadvantage of the slow aperture, in some cases. On the other hand, I remember that Chasseur d'Image tested both IS/non IS versions of the Canon 300mm f/4.5 a while ago and did not notice any significant difference in performance. To the contrary, at 1/15s, the proportion of sharp images was much higher with the IS lens (on stationary subjects, of course). Nicolas.
