posted on Sep 2, 2009 at 8:17AM
Tamron Adds Stabilization to SP AF 17-50mmBy Jared Newman
Tamron's giving its versatile 17-50mm lens a bit of extra stability, adding Vibration Compensation to combat camera shake.
The SP AF 17-50mm F/2.8 XR Di-II VC LD Aspherical (IF) is a lot like its similarly-named predecessor, but with a stabilization mechanism that controls camera shake on three planes. Tamron claims that this was accomplished without “materially increasing” the weight or size to the lens, and with a filter thread of just 72 mm. A comparison of new and old lenses reveals that the new one is about 5 ounces heavier, 0.2 inches wider and 0.5 inches longer.
Designed specifically for DX-format cameras, the wide-angle to short telephoto (26-78mm equivalent) lens works only with Nikon-mount DSLRs for now. A Canon-mount version will come along “shortly after” the Nikon-mount version with built-in motor becomes available.
Aside from the added image stabilization, the new lens includes Extra Refractive Index glass for correcting optical aberrations, and two low dispersion lens elements for fixing chromatic aberrations. The design of the lens optimizes the angle at which light hits the image sensor. Additionally, there are multiple layers of Broad Band Anti-Reflection coatings to reduce ghosting and flare.
Other features include a zoom-lock mechanism that keeps the lens barrel from extending in transit, a flower-shaped hood for light shielding and a minimum focus distance of 11.4 inches across the zoom range, with macro capability of 1:4.8. The lens is constructed of 19 elements in 14 groups.
Tamron will start selling the SP AF 17-50mm on September 17, but hasn't revealed pricing yet.