The high power zoom lens was designed essentially for DSLR cameras with APS-C sized sensors. Tamron 18-200mm f/3.5-6.3 Aspherical Di-II LD IF XR was noted as an all-in-one lens that is suitable for practically all of your photographic needs without changing lenses. Tamron 18-200mm features a focal length equivalent to 28-300mm in 35mm format. The designated XR- Extra Refractive Index - minimizes an array of aberrations to the absolute lowest while achieving stunning downsizing. The lens offers zoom lock mechanism, internal surfacing coating reducing flare and ghosting, and top-of-the-line Di-II design. The 18-200mm concerts optical performance, flexibililty and convenience in the lightest, compact zoom lens to deliver the highest standard image clarity.