Ef 40mm f28 stm 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 features bullportable pancake design bullsmooth quiet stm focusing when shooting movies on compatible cameras bullfast f28 maximum aperture for low light shooting bullclose focus to 03m bullfast quiet af for pin sharp results bullgreat image quality right across the