Canon’s triple-layered diffractive optical element (DO) significantly reduces the length and weight of the lens. Distortion and vignetting slightly better than non-DO version. IS adds appeal.
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.
|Full-Time Manual Focus Override:||No|
|Minimum Focal Length:||70 mm|
|Maximum Focal Length:||300 mm|