Details:

The 90-300mm f/4.5-5.6 USM from Canon is a compact, lightweight telephoto zoom lens for Canon EF-mount. The communication speed between the lens and the camera is faster due to a new high-speed CPU, and a new AF algorithm has been used to offer one of the fastest autofocus speeds for its class. All the lens elements are manufactured from environmentally-friendly lead-free glass and a redesigned electromagnetic diaphragm (EMD) provides an aperture which is nearly circular at the widest settings for an improved out-of-focus background effect. All this is complimented by a micro USM (Ultrasonic Motor) motor for quiet operation.