Blue Macro Af Auto Focus Extension Tube Set 13mm 21mm 31mm for Canon Dslr SLR 5d 6d 60d 7d 70d 700d Macro Extension Tube moves the lens farther from the film or digital sensor. The farther away the lens is, the closer the focus, the greater the magnification. This extension tube set is SUITABLE FOR CANON DSLR/Film SLR/LENS ONLY.