Telephoto lens series canon ef lens mount canon ef lens speed 2 focal length 100 mm suitable for sensor types aps c full frame construction prime lens area of use portrait photography night photography astrophotography focus manual focus internal focus auto focus af motor ultrasonic motor usm closest focusing distance 90 cm lens construction groupselements 68 number of aperture blades 8 minimum aperture 22 max aperture 2 filter thread 58 m