Originally published September 2005.
WHAT YOU SHOULD KNOW:
The fourth generation of Sigma's pro-caliber, EX-series 28-70mm f/2.8, this version features a smaller filter size (from 77mm down to 67mm), improved coatings to control ghosting with digital SLRs, a significantly closer focusing distance (from 19 down to 12 inches), and now a zoom lock. Compared to the Tamron 28-75mm f/2.8, it's slightly more compact (3.4 vs. 3.6 inches), but otherwise physically similar and comparably priced ($359).
Matte black with focusing and zoom scales in contrasting white, the lens features amply sized focusing and zoom rings clad in a ribbed, rubberlike material for pleasing finger traction. Compact for the class, it's half a pound lighter and 1.5 inches shorter than Nikon's more expensive 28-70mm f/2.8 ED AF-S ($1,500). As befits a pro-caliber lens, both focusing and zoom actions are very well-damped; zoom creep is highly unlikely. Lacking Sigma's silent HSM focusing motor, the lens' AF noise levels are noticeably louder than Canon's USM-enabled 24-70mm f/2.8L EF ($1,150), for example, but not objectionable.
IN THE LAB:
SQF performance was excellent at the three tested focal lengths, and distortion as determined in DxO Analyzer tests, was well-controlled, with slight pincushioning (0.69% and 0.80%) at 50mm and 70mm (respectively), and slight barrel distortion (0.93%) at 28mm. Light falloff was gone by f/5.6 at all three focal lengths, an average result for pro-quality glass. At the universal close-focus distance of 12 inches, magnification ratios ranged from 1:7.7 at 28mm to 1:4.5 at 70mm, an average performance. (The 24-70mm Canon mentioned above reaches 1:3.5 at 70mm.)
A sharp, compact, fast, and ruggedly constructed pro-caliber lens that's priced for all users, Sigma's newest 28-70mm f/2.8 is hard to fault.
28-70mm (29.24-69.56mm tested), f/2.8 (f/2.91-3.04) tested), 14 elements in 12 groups. Focusing turns 50 degrees counterclockwise. Zoom ring turns 60 degrees clockwise. Focal lengths marked at 28-, 35-, 40-, 50-, and 70mm.
• Diagonal view angle: 75-34 degrees.
• Weight: 1.13 lb.
• Filter size: 67mm.
• Mounts: Canon AF, Konica Minolta AF, Nikon AF, Pentax AF, Sigma AF.
• Included: Lenshood, softcase.
• Street price: Approx. $359.