Sigma 18-200mm f/3.5-6.3 OS

One of Sigma’s newest lenses, this is the Optically Stabilized version of the 18-200. It is an ideal ‘one lens’ solution for Canon 1.6 frame cameras (T1i, 50D) with a huge 11X range and optical image stabilization to reduce blurring from camera shake. The lens is internally focusing so the front element doesn’t rotate, making the use of circular polarizing and other filters particularly easy. Very small and light weight, this is a superb travel and vacation lens. NOTE: This lens does not work on full frame bodies (5DMkII, 1DsMkIII).

Roger’s take: A surprisingly good lens given its 11X range. The optical stabilization works well and the lens is good enough to give very nice prints up to 8 X10. Its a compromise of course – you can’t have 11X zoom and the sharpness of an “L” prime. But its much better than I expected it would be, its small and easy to carry, and the range is will cover most vacation needs in one lens.

This and the Tamron 28-300 are very similar in size, image quality, and effectiveness of the stabilization systems. I think the choice comes down to whether you want the extra telephoto length of the Tammy, or the wider angle shots the Sigma can provide.

High Risk Lens: The Sigma 18-200 lens has a higher failure rate than most lenses in our lineup.

• How high? About 2% of rentals.
• Why? We can’t be sure. Sigma lenses as a rule have more problems than other brands.
• What’s the point? We’re letting you know on the front end make sure you order this lens in time to check it out before you leave for vacation or schedule your big shoot and to forewarn you that problems do occur. We can send a replacement if it has a problem, but we can’t send a replacement Friday night to get to you you Saturday morning.
• Type of problem: The front section of the lens comes loose and in one case actually separated from the lens.