A versatile, compact pancake lens. A fast maximum aperture enables low-light shooting and depth-of-field control. STM provides smooth quiet autofocus when shooting video with compatible cameras. Never be without your EOS. The compact pancake EF 40mm f/2.8 STM is very thin, so you’ll always be able to take your DSLR with you. Fast, accurate autofocusing ensures pin-sharp images even in tough conditions. Movie Servo AF with STM uses stepping-motor technology for smooth, quiet autofocus when filming on compatible Canon DSLRs.