Designed to provide a wide zoom range in a compact and lightweight form factor, Canon's EF-S18-200mm f/3.5-5.6 IS telephoto zoom lens can only be used with cameras that have 'APS-C-sized' image sensors. Supporting a zoom range of approximately 11 times, it covers a focal length equivalent to 29-320mm in 35mm format but weighs only 595 grams. Built-in image stabilisation provides approximately four f-stops of shutter speed advantage and the stabilisation system can detect when the camera is panned.
Consisting of 16 elements in 12 groups, this lens is made from environmentally friendly lead-free glass and contains UD glass and high-precision aspheric elements. Internal Focus (IF) mechanisms provide smooth focusing and make it easy to use angle-critical filters, such as polarisers and graduates. The lens comes with front and end caps but no lens hood; although an EW-78D lens hood is available as an optional accessory.
A gear-driven micro-motor system is used for autofocusing, instead of the USM ring-type motors found in many other Canon lenses, which are faster and more accurate. The lens also carries electronic contacts that provide information for E-TTL II flash metering.
A small zoom lock button is located near the camera end of the lens barrel on the lower right corner, where it is (just) reachable when the camera is in use. It's necessary as the lens tends to extend when it is carried facing downwards on the camera.
Mounted on the side of the lens barrel are two slider switches. The top switch covers auto and manual focus while the lower switch is for turning the image stabiliser on and off.
Margaret Brown
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