L series robust construction Image stabiliser Magnesium alloy build For the wildlife or sports professional photographer the Canon EF 800mm f/5.6 IS USM possesses image stabilisation, which can eliminate handshake at when working at lower shutter speeds, and a quiet focus motor for eliminating excess noise when photographing animals. Although the lens can be used on an APS-C body, full frame DSLRs would benefit more from the huge amount of detail able to be captured by this long focal length lens. The closest rival is the Sigma 800mm f/5.6, which differs in the absence of optical image stabilisation. The tripod mount around the barrel can be rotated around the lens to sit where the photographer requires it, and the image stabiliser can allow the camera to use shutter speeds up to four times slower than normal without affecting sharpness. The L series construction makes the Canon EF 800mm f/5.6 IS USM capable of standing up to moisture or dust, so a sudden rain shower will not render the lens inactive. Having a magnesium alloy frame makes the Canon EF 800mm f/5.6 IS USM impressively robust without adding a vast amount of bulk.