John Fox , Apr 28, 2008; 08:03 p.m.
I owned a sigma 28-200 and a canon 28-105 USM II (3.5-4.5). The canon was used all the time. More light, excellent speed in focus and silent, great feel, good sharpness and contrast. I loved it compared to the 18-55 normal digital lens. The sigma was ok. I never felt it was sharp, but is was very usable. From what I have read, sigma made many 28-200 lenses, some better than other. I would try and get a longer lens to balance out your lens selection and get ride of the sigma. Take some shots and see what you want to do with your shooting. have fun.