Field-test of the Canon EF 100mm f/2.0 USM Telephoto lens. The Canon EF 100mm f/2.0 USM is a medium telephoto lens popular for its large aperture and compact size. Aberrations are minimized using a newly-designed rear focusing optical system as opposed to the helicoids version employed in the discontinued manual focus FD 100mm f/2.0 lens. High contrast, sharp imaging performance is obtained over the entire aperture range. Like its EF 85mm f/1.8 USM counterpart, this high quality lens is equipped with an Ultrasonic Motor for super-quick AF response. Full-time manual focusing operation is designed with the optimum amount of torque for a familiar operational feel to previous manual focus lenses. The Canon EF 100mm f/2.0 USM Telephoto Lens The large opening as seen through the rear elements Comparison of the EF 100mm f/2.0 (left) and EF 50mm f/1.4 EF 100mm f/2.0 USM (left) and the EF 85mm f/1.8 USM Having tested the EF 85mm f/1.8 USM in last issue, the Canon EF 100mm f/2.0 USM telephoto lens is the next. It has always been a very difficult choice for EOS users to choose between these two EF USM lenses. Both are fast aperture lenses designed for available light shooting as well as portraiture. Plus other subjects where compactness and fast AF system of these lenses made them ideal to carry around in the bag or vest. << Back to Main . 1 . 2 . 3 .