Fotga 25mm AF Auto Focus Macro Extension Tube DG II for Canon EOS EF EF-S Mount 1D/1Ds, Mark II, III, IV, X, C, 5D, 5D Mark II/III 7D,10D,20D,30D,40D,50D,60D,60Da,Rebel XT, XTI, XS, XSI T1 Dslr Camera The Automatic Macro Extension Tube 25mm DG II is designed to enable a lens to focus closer than its normal set minimum focusing distance.Getting closer has the effect of magnifying your subject (making it appear larger in the viewfinder and in your pictures) It is exceptionally useful for macro photography, enabling you to convert almost any lens into a macro lens at a fraction of the cost while maintaining its original optical quality The extension tube have no optics. It's mounted in between the camera body and lens to create more distance between the lens and film plane.By moving the lens father away from the film or CCD sensor in the camera, the lens is forced to focus much closer than normal The greater the length of the extension tube, the closer the lens can focus.It is with electronic contacts,which make it support automatic focusing,automatic exposure,etc.Designed with 1/4&quot; tripod mount, make it convenience using on the tripod Compatible with All EOS EF EF-S Mount lens,such as 1D/1Ds, Mark II, III, IV, X, C, 5D, 5D Mark II/III 7D,10D,20D,30D,40D,50D,60D,60Da,Rebel XT, XTI, XS, XSI, T1 Cameras