I've read some reviews on the web which claim that the 28-200 is much more sharper and has a better contrast upon the 28-105. Which one of these two should i choose ?

-- Raz Aderet (conarius@netvision.net.il), March 15, 2002

Answers

Where are those reviews? They run contrary to every other similar comparison I've seen.

Canon's MTF graphs suggest that the 28-200 is better in the very center at 28 than the 28-105 is but that the 28-105 beats it once you're more than 5mm or so from the center. Since the graphs on Canon's U.S. Web site only show the extreme ends of the zoom range, 28 is the only focal length at which the MTF graphs can be compared.

If you want the best optics, pick the 28-105. If you want the best convenience and want more than the range of the 28-105, get the 28-200.

-- Steve Dunn (steved@ussinc.com), March 15, 2002.

Well, I suppose if you look carefully at the pictures of those two lenses at the Canon USA EF lenses website, you can see that the 28-200 indeed looks better than the 28-105, which suffers from too much unsharp masking and digital noise. See:
  EF 28-200mm f/3.5-5.6 USM
  EF 28-105mm f/3.5-4.5 II USM

Is this what you mean? :-)

-- Julian Loke (elan7e-owner@yahoogroups.com), March 17, 2002.