High performance l series telephoto zoom lens constant f28 maximum aperture four ud lens elements 15m minimum focussing water and dust resistant eight bladed aperture ring type usm af motor the ef 70 200mm f28 l usm is a professionally quality fast aperture telephoto zoom lens popular with wildlife and sports photographers as well as those shooting weddings and portraiture a zoom as good as a prime lens one of the finest telephoto zoom lenses in the ef l