This telephoto zoom lens has been developed as a new model of the high-performance Star (*) series, which assures exceptional image rendition with edge-to-edge sharpness by effectively compensating various aberrations to a minimum. When mounted on a PETAX K-mount SLR camera body, it provides a zoom ratio of approximately 2.9 times to cover a telephoto range from 107mm to 307mm in the 35mm format. Since it provides a large maximum aperture of F2.8 over the entire zoom range, it is ideal for portraiture with beautifully defocused foreground/ background and sports photography demanding high shutter speeds to freeze the action. Its image circle is optimized to cover even the image size of 35mm film format SLR cameras. As the result, it not only assures brilliant, high-resolution images without compromising the sharpness at edges even when mounted on an existing PENTAX digital SLR camera body, but it is also capable of accepting future models with larger image sensors without modifications.