DA* 16-50mm vs. Sigma and Tamron 17-50mm F2.8 Comparison

Conclusion: Tamron

Though the Tamron 17-50mm f/2.8 XR Di II has been followed by an updated models (the "VC," or Vibration Control, version), it remains for many the more desirable of the two lenses. A large part of this is due to its low price relative to the competition, but much is also owed to its reputation for superb performance. Our tests bear out this reputation to a large extent. The Tamron is capable of producing some of the sharpest results out of this pool of lenses. While it's beaten by the Sigma when used wide open in terms of sharpness across the frame, it pulls ahead when stopped down. While its vignetting characteristics aren't so great, it's the best of the bunch in terms of flare resistance (by a large margin) and bokeh (by a slim one). It fares better in terms of distortion than the far more expensive Pentax offering (though of course it doesn't go to 16mm on the wide end).

However, it's a law of the market that a lower price can't come without cutting some corners, and this lens is no exception. The build quality is decidedly subpar compared to the tank-like Pentax and Sigma construction. The materials feel cheaper, and the mechanical operation is a bit more bargain-basement—particularly the focusing ring, which is tiny and is a horror to use in MF mode. The lens lacks an AF/MF toggle and full-time manual focus, though it does offer a zoom lock, which the Pentax doesn't. All of that said, it's also a heck of a lot smaller and lighter than either the Pentax or the Sigma, which will please your back, neck, and wrists after a long day of shooting.

Autofocus performance, while noisy, was quite good—the traditional screwdrive was just as quick as the micro-motor-driven systems in the other two lenses. The AF system did make more micro-corrections after its initial focus lock than did the SDM and HSM systems. More disappointing was the need for AF correction at 50mm and f/2.8, where the Tamron lens consistently backfocused. It's our feeling that this was sample variation rather than an endemic problem, but it was frustrating nonetheless.

Value

Currently being offered at $459.00 by B&H, with a $25 rebate bringing the total to $434, the Tamron lens is the cheapest in this test by a vast margin—$230 cheaper than the Sigma and a whopping $465 less than the Pentax. Its optical performance is better than the twice-as-expensive Pentax and essentially on par with the Sigma, though it loses out heavily in terms of build quality, features, and perhaps resale value. On the other hand, it's quite small and light for the class. Taking all of these factors into consideration, and assuming you score a good copy or buy from a reputable retailer with a good return policy, we have no qualms about calling the Tamron the best value of the bunch—and by quite a distance.

Pros

• Exellent sharpness stopped down; very good wide open
• Superb value
• Very small and light
• Best flare resistance and bokeh
• Did we mention cheap?

Cons

• Subpar build for a pro-class lens
• Short on features
• Suspect quality control; possible backfocus
• Not the sharpest across the frame, wide open

Rating