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  Reviews by: Renny  

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Tamron 28-75mm f2.8 XR Di Zoom AF

28-75mm
Review Date: Aug 20, 2005 Recommend? yes | Price paid: $360.00 | Rating: 9 

 
Pros: Constant f2.8 aperture, reasonably sharp across the entire frame at f3.5. Good sharpness by f4. Even at f2.8 the center of the frame is sharp. Although polycarbonate, the build seems sturdy. Inner focus is nice--the end of the lens doesn't rotate when focusing which is handy when you're using a polarizer.
Cons:
Heavier than you might expect. (Although according to other reviewers lighter than competing f2.8 zoom lenses.) I kind of wish it was an 18-75 lens, but that would undoubtedly require that it be bigger and heavier.

Let me start by saying that I don't have any experience with 'L' lenses. I was looking for something affordable and sharp that could function in lower light than my 18-55 kit lens. I ran some tests to compare the 28-75 to the kit lens. I tacked a newspaper to the wall and set up a tripod. I used the timer function--it seemed to give me better results than just mirror lockup, and I couldn't seem to get both to function at the same time. Sharpness at the center of the frame is no contest. The 28-75 is sharper at f2.8 than the kit lens stopped all the way down to f10. (Maybe my copy of the kit lens is bad? Nevertheless, the 28-75 seems sharp.) The 28-75 may get a little sharper when stopped down, but I'm very impressed with the center sharpness for f2.8.

Corner/edge sharpness is a slightly different story. At f2.8 the 28-75 is maybe just a little less sharp than the kit lens at f5.6. They're close, though. At f3.5 the 28-75 sharpens up nicely and definitely beats the kit lens at f5.6. The kit lens does sharpen up from that point, but not as quickly as the Tamron.

I've only had the lens a couple of days, but I haven't seen any front-focus issues yet on by 20D. I'll edit my update my post if I have any problems.