Canon offers five different 70-300mm zoom lenses in its product lineup. Why so many? They obviously think this is a popular and practical focal length range and I happen to agree. I even own one of them myself—the EF 70-300mm f/4-5.6 IS USM—but the EF 70-300mm f/4-5.6L IS USM tested is the mac daddy of ’em all. Part of the reason for its high price tag ($1599) is that it’s the only one of the five lenses that is resplendent in white paint (the better for TV cameras to see), making it part of the “L” series. (See “Just For The ‘L’ Of It.”) Canon’s L lenses typically have wide apertures fixed throughout the zoom range but in this case all five lenses in this focal length range have identical f/4-5.6 apertures.
The new Canon EF 70-300mm f/4-5.6L IS USM telephoto zoom lens features two Ultra Low Dispersion (UD) elements for improved image quality and reduced chromatic aberration. It incorporates a floating focusing mechanism for sharpness from close-up (3.9 feet) to infinity plus an Image Stabilization (IS) system that Canon claims increases usability by approximately four stops. The IS system includes a function that allows it to continue to operate even when the camera or the lens, the latter being a better idea, is mounted on a tripod. There’s an optional ($189.95) Canon Tripod Mount C for mounting on a tripod or monopod but I was unable to get one for testing. The lens is dust- and water-resistant and features a Fluorine coating that resists smears and fingerprints and significantly eases lens cleaning, but that doesn’t make me suggest less vigorous lens protection. More later.