I recently picked up Sigma's 17-50mm F2.8 EX DC OS HSM lens (from herein referred to as Sigma 17-50mm) as I had a need for fast lens covering the standard zoom range. With a few weddings ahead of me I thought this would be a good lens to have in my kit, and it fit my budget, coming in at right around $500 USD.
After much online research comparing the Sigma to Tamron's similar offering, I decided to go with the Sigma as I had used one of their lenses in the past and quite enjoyed it. Nonetheless, before the lens showed up, I'll admit I wondered what quality of glass I would be getting at such a reasonable price.
Before I get into the specifics of the lens, I'm going to put this post in a little context. I'm not a lens reviewer. I know basically what to look for when assessing a lens, but I'm not set up for or familiar with all of the specific tests that more knowledgeable lens testers are in this regard. That being said, this review will be more basic than others, essentially, just a guy shooting with a lens and looking for some of the more obvious flaws one might pick up.
After taking the lens, its padded case, front and rear covers and hood out of the box, I gave it a once over to make sure visually everything looked intact. All screws were in place, and a quick double check with a jeweler's screwdriver confirmed all showing hardware was tight. No audible sounds were heard when giving the lens a little shake.
The lens' zoom operated smoothly, though much tighter feeling then my other lenses. When extended, the lens measures just over 3.5", with the front element telescoping out from the barrel. I was briefly confused by the zoom ring operation, which is reversed from the Nikkor lenses I'm familiar with. Fully extended, I could feel no play when gently rocking the front element in the barrel. A quick switch of the AF/M switch proved that the manual focus ring also turned smoothly.
Despite being largely plastic on the exterior, at 565g, it's not a light lens, but certainly nothing so heavy that I wouldn't keep it mounted as a walk-around lens. It does have a metal bayonet, which is something I always look for when purchasing a new lens -- learned this lesson when a plastic mount on a kit lens broke, resulting in a bent aperture arm, and a repair bill from Nikon USA!
After the visual inspection, I felt pretty good about my purchase. Of course, the real tests hadn't even begun.
More articles that might interest you