Lens Test: Sigma 17-50mm f/2.8 EX DC OS HSM AF

SPECIFICATIONS:

17–50MM (17.53–49.71mm tested), f/2.8 (f/2.83–2.81 tested), 17 elements in 13 groups. Focus ring turns 50°. Zoom ring turns 70°. Focal lengths marked at 17-, 21-, 28-, 35-, and 50mm. DIAGONAL VIEW ANGLE: 72–27degrees
WEIGHT: 1.29 lb
FILTER SIZE: 77mm
MOUNTS: Canon AF, Nikon AF, Pentax AF Sony AF, Sigma AF
INCLUDED: Lenshood
STREET PRICE: $670

TEST RESULTS:
DISTORTION: At 17mm, 0.48% (Visible) barrel. At 28mm, 0.03% (Imperceptible) pincushion. At 50mm, 0.13% (Slight) pincushion.
LIGHT FALLOFF: At 17mm, gone by f/3.5. At 28mm, none. At 50mm, none.
CLOSE–FOCUSING DISTANCE: 9.54 inches.
MAXIMUM MAGNIFICATION RATIO: At 17mm, 1:7.64. At 28mm, 1:5.44. At 50mm, 1:3.87.
IMAGE STABILIZATION: 1–2.5 stops.