This user-friendly telephoto zoom lens covers a broad zoom range from 70mm to 300mm. the built-in image stabilizer (IS) mechanism counteracts the effects of camera shake by approximately three shutter speed steps. In addition to “camera shake correction mode 1” suited for shooting stationary objects, this lens is also provided with “camera shake correction mode 2” that offers the easy enjoyment of panning filled with a sense of speed. Only environmentally-friendly lead-free glass is used in the optical system made up of 15 elements in 10 groups and a UD lens, which achieves high image quality at all focal lengths, is employed in the first lens of the third group. Furthermore, the optimization of lens positioning and coating minimizes the flare and ghosting that often occur in digital cameras. A zoom ring lock keeps the lens at its shortest length in the wide position and prevents the lens barrel from extending and striking any objects when the lens is being carried attached to a camera with a strap. The use of micro USM lens drive, a high-speed CPU and an optimized autofocus algorithm ensures autofocusing that is both quiet and fast. The image stabilizer mechanism and the optical system utilizing a UD lens, combined with other features such as the zoom ring lock function and relatively compact size and weight, make this a highly advanced and user-friendly lens.