The Fotodiox Pro auto macro extension tube for Canon RF-mount mirrorless cameras is a space that increases the distance between your camera and lens while enabling electronic functions. The increased distance created by extension tubes allows your lens’s focusing distance to be shortened for macro use as well as increasing the focal length. The gold-plated contacts on the extension tube allow autofocus, autoexposure, aperture control, and image stabilization; however, autofocus can be slow at the close distances. The optical qualities of the lens are also preserved sine there are no optics inside the extension tube. With all these features, the Fotodiox Pro auto macro extension tube for Canon RF-mount cameras is a great alternative to expensive macro lenses. Canon RF Mount Mirrorless Cameras: EOS R, EOS RP Notes: Does not work with the Canon RF 35mm f/1. 8 ISD Macro STM Lens, the lens will not fit the macro tube Extension tubes work best with short to medium focal lengths, they are less effective with telephoto lenses Extra magnification also magnifies camera shake as well as the subject, tripod use is recommended Be sure to use the smallest aperture (largest number) on your lens to give you adequate depth-of-field for better quality images Each ring brings you closer to the subject as you increase the distance between lens and camera Different lens lengths will require a different distance to be used from the subject, if the subject is not in focus move the camera closer or further from the subject until the subject comes into focus The effectiveness of extension tubes decreases as focal length increases. You will need to be careful when working with extreme wide-angle lenses as the focusing distance required may be closer to the lens than physically possible (ie you'd hit the front lens element before you achieve focus). All pictures are for illustration purposes only. Actual product may vary slightly due to ongoing improvements in design.