One of only two lenses that contains both refractive and diffractive glass elements, this image-stabilized tele zoom is dramatically more compact -- and expensive ($1,143, street) -- than its refractive-only Canon ($549, street) or Nikon ($479, street) counterparts. Unlike more common refractive optics, diffractive optical design is based on how light rays bend when forced to move around (not through) an obstruction -- in this case, a pattern of molded, sawtooth, Fresnel-like, concentric circles. A full-frame lens, it scales up to a 105-450mm on Canon EOS Digital Rebel models.
About one-third smaller than other 70-300mm stabilized lenses, it's also a few ounces lighter. Ribbed and rubber-clad focus and zoom rings turn evenly and smoothly. On our EOS 5D test camera, autofocus action is silent, rapid, and sure. In addition to AF-, IS-, and IS-mode switches, a fourth locks the zoom in its 70mm position.
IN THE LAB
SQF tests found sharpness and contrast in the Excellent range at 70mm and 200mm, dipping to Very Good at 300mm, roughly equal to Canon's refractive version. DxO Analyzer 3.1 tests found Slight barrel distortion at 70mm (0.11%) and Visible pincushion distortion at 200mm and 300mm (0.34% and 0.33%, respectively), slightly better than the non-DO lens. Light falloff left the corners by f/5.6 at 70mm, and by f/8 at 200mm and 300mm, an average performance, but again slightly better than the refractive zoom. Maximum magnification ratios at the uniform close-focusing distance of about 52.5 inches were 1:14.25 at 70mm; 1:6.33 at 200mm; and 1:4.75 at 300mm (less power than Canon's claimed 1:4). Our image stabilization tests were based on DxO's Blur analysis: Three different users gained 2.5 to 3 stops of handholdable shutter speeds.
Willing to pay to travel light and save space? You won't be disappointed with this remarkably bulk-free, satisfyingly sharp, full-frame, stabilized tele zoom.
70-300mm (74.15-282.15mm tested), f/4.5-5.6 (f/4.74-n.a.* tested), 18 elements in 12 groups. Focusing turns 160 degrees counterclockwise. Zoom ring turns 80 degrees clockwise. Focal lengths marked at 70-, 100-, 135-, 200, and 300mm.
• Diagonal view angle: 34-8 degrees.
• Weight: 1.63 lb.
• Filter size: 58mm.
• Mounts: Canon AF.
• Included: Lenshood, soft case.
• Street price: $1,143.
*Unable to measure due to instrument limitation.