Canon EF 70–200mm lens

The EF 70–200mm lens is a telephoto zoom lens made by Canon Inc. The lens has an EF mount to work with the EOS line of cameras.

The lens comes in five different versions, all of which have fixed maximum aperture at all focal lengths and are L-series lenses.

The f/4 non-IS version, the least expensive L-series lens Canon makes, is popular among weight-sensitive landscape photographers and hobbyists who want L lens quality without spending thousands of dollars. The f/2.8 versions are popular among event photographers and photojournalists where the lower light capabilities are required; some portrait photographers also prefer this lens for the improved background blur produced by the f/2.8 aperture. The non-IS f/2.8 version was released in 1995 and replaced the EF 80–200mm f/2.8L lens. The IS version lenses use circular eight-bladed diaphragms which maintain a nearly circular aperture when stopped down by up to two stops. The f/2.8 and f/4.0 image-stabilized versions also feature weather sealing (resistance to dust and water) when mated to a weather-sealed camera to such as the Canon EOS 1D-series bodies. Weather sealed Canon products are not completely sealed from the environment, they are merely more resistant than non-sealed versions. These lenses are compatible with the Canon Extender EF teleconverters. Due to its internal zooming mechanism, there is never any "lens creep" when pointing this lens at the ground.

When used with a Canon APS-C (1.6x crop) DSLR camera or APS-H (1.3x crop), the field of view of this lens is equivalent to a 112–320mm on an APS-C sensor, or 91–260mm on an APS-H sensor. This is due to the crop factor inherent with APS-C or APS-H (crop) sensor digital SLR cameras.

The most frequently pointed-out problem with this lens is the placement of the IS and AF buttons, that makes them prone to accidental flipping during hand-held shooting. Some photographers solve this simply by covering the buttons with a piece of gaffer tape. In recognition of this issue, the most recent of these lenses (the f/4L IS USM model and recent f/2.8L IS USM lenses) uses switches designed to reduce the incidence of accidental switch activation.

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