Featuring the latest 3-stop Image Stabilizer for outstanding camera shake reduction, the EF 70-300mm f4-5.6 IS USM zoom lens also features super responsive autofocus. Replacing the popular EF 75-300mm f4-5.6 IS USM, the world’s first interchangeable lens with Image Stabilizer (IS), the lens is expected to appeal to serious amateur nature and sports photographers looking to achieve outstanding results while shooting hand held.
Image Stabilizer
IS dramatically reduces image blur caused by camera shake. The EF 70-300mm f4-5.6 IS USM features Canon’s latest 3-stop IS, a one-stop improvement over its predecessor. Gyro sensors detect unwanted vibrations, triggering the corresponding movement of a correcting lens group perpendicular to the optical axis. The EF 70-300mm f4-5.6 IS USM provides 2-mode IS for shooting immobile subjects.
Superb autofocus
The micro USM motor found in the EF 70-300mm f4-5.6 IS USM employs ultra-sonic frequency vibrations to drive auto focus with unrivalled speed and near-silent operation.
Pleasing defocused background
The EF 70-300mm f4-5.6 IS USM employs an electro-magnetic diaphragm (EMD) with a circular aperture.
Image quality
By optimizing Super Spectra lens coatings and lens element shaping, Canon’s engineers have been effective in suppressing flare and ghosting–more prone to occur with digital cameras due to reflection off the image sensor. By increasing light absorption, coatings reduce reflections off lens element surfaces to deliver crisp, undistorted images with natural color balance.
Focal length translates to 112-480mm equivalent in 35mm film format when fitted to EOS 20D and EOS 350D cameras.
When used in conjunction with Canon’s range of EX Speedlite flash units, the lens passes distance information to the flash algorithm for markedly improved flash exposure metering.
Accessories for the EF 70-300mm f4-5.6 IS USM include the lens hood ET-65B and the lens pouch LP1222.
You may often hear the terms ‘fast’ or slow’ to describe a lens or aperture. This has nothing to do with the speed of operation, but to the size of the maximum possible apperture (usually quoted as a suffix to the name of a lens). A Lens with a maximum aperture of f/1.4, for example, is ‘faster’ than similar lens with f/2.8. Because the aperture is larger, faster shutter speeds can be used, which is especially useful in low light conditions.
Another practical benefit of a larger aperture is that the extra light that enters the lens leads to brighter viewing on the camera’s viewfinder-again, useful in low-light conditions.
Zoom lenses often quote two maximum apertures, for example, 18-70mmf/2.8-4. This means that the maximum aperture at the 18 mm end is f/2.8, while the maximum aperture at 70mm if f/4. In reality, the actual hole is the same size but the added focal length (and the maths) changes the f-number. There are several lenses available with a fixed maximum aperture that doesn’t change throughout the focal range, such as Sigma’s 70-200mm f/2.8 lens. These lenses are usually expensive though, and because of the large optics needed to perform the trick, quite heavy as well.
A portrait taken in front of a window with a great view in the backgorund sounds like a good scenario for a great photograph. However, the contrast range between your subject and the background is likely to be too great for the sensor to handle. If the camera’s meter in influenced by the background, the subject will be too dark, maybe even a silhoutte. To get a correct exposure on the face you’ll need to take a selective light reading, though of course all the background detail will then be overexposed. The only way to balance the two is to increase the light level on the face (using either reflectors, or flash) to more closely match the background level.
Bracketing
Bracketing allows you to shoot additional exposures either side of your first reading, giving you a greater chance of obtaining an optimum exposure. The camera calculates the extra exposures based on your initial reading and by what increment you wish to bracket your shot by. It then takes a series of exposures at the different settings in quick succession.
