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.
Hands On:
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.
Julia Silber
more : popphoto
Subscribe to:
Post Comments (Atom)
0 comments:
Post a Comment