Macro metal Auto Focus Extension Tube for Canon EOS Camera Red 5d 6d 60d 600d 7d 70d 700d 1100d 500d 650d Canon SLR Cameras CANON EF EF-S Lens This Macro Extension Tube Set includes 3 extension tubes:13mm,21mm,31mm You may mount the tubes between lens and camera body to get your choice of macro ranges. There are totally 8 combinations It moves the lens farther from the film or digital sensor. The farther away the lens is, the closer the focus, the greater the magnification Designed with all the circuitry and mechanical coupling to maintain auto focus and TTL auto exposure with Canon DSLR Body. This extension tube does not affect image quality as there is no optics inside