The 28-75mm Di Zoom
Billed as the “world’s lightest and most compact fast standard zoom lens” the new Tamron SP AF 28-75mm f/2.8 XR LD Di Aspherical [IF] Macro zoom is surprisingly small for an f/2.8 model. When zoomed to 75mm, the internal barrel extends by 1.5”, but the overall length is still shorter than average. Nicely finished in matte black, the barrel features a rotary zoom mechanism, wide, rubberized focus and zoom rings, and a focal length and distance scale. The manual focusing ring is quite well damped, with enough friction for convenient operation. Zooming action is adequately stiff so I found no need for the lock mechanism that can prevent the barrel from extending when the lens is pointed upward or downward. Although the focus ring rotates during AF operation, focus response is fast and fairly quiet; thanks to the wide maximum aperture, the system was reliable even in the low light.
As noted in our Specs chart, the 28-75mm Di zoom incorporates three types of special glass elements for optimum image quality at all focal lengths.
At all focal lengths and all f/stops, this lens produced digital images and color slides with very high contrast, sharpness, clarity, and resolution of fine detail. Particularly in the mid range of focal lengths, and especially at f/4-f/11, image quality is superlative. Edge sharpness matches central sharpness, impressive performance with any zoom lens. Flare was very well controlled, a real benefit on sunny days in extreme sidelighting. In all of my images, brightness is consistent across the entire frame, at all focal lengths, from f/4-f/22. My best digital images made for exhibition quality 11x17” ink jet prints and my Velvia 100F slides are also technically exceptional.
Di: Digitally Integrated Design, is a designation Tamron puts on lenses featuring optical systems designed to meet the performance characteristics of digital SLR cameras. The most compact and lightest in the history of fast zoom lenses.
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