Kaavie -The Premium Aluminum Mount Version (Rugged and Lightweight, Best Option Extended Goal) - Set Automatic Extensions Ring for Canon Eos Ef / Af 3 Rooms: 13 Mm, 21 Mm, 31 Mm Bayonet - Canon EOS Canon EOS 1d C, 1d X, 1d Mark I-iv, I-1ds Mark Iii, 5d Mark I-iii, 6d 7d 60d 50d 40d 30d 20d 10d 1100d 1000d 650d 600d 550d 500d

This doesn't work as smoothly as the more expensive extension tubes, but it is OK for occasional use. Important things that seem right are: good autofocus function, compliant pins that will not damage camera contacts, functional catch locking each tube in place.

This extender set adapts well to my EOS cameras. Just make sure you push correctly on the release tabs when removing from camera. My Canon EF, and EF-s lenses all auto focus and meter with these extenders, although I believe the proper way to use them is to focus manually and then move the camera back and forth to attain focus.Since we are dead in the middle of winter here in the cold north, it will be well past the middle of spring time before the flowers bloom and I get a good chance to use these extenders, but in testing them indoors, they work as intended. I expect them to work properly and hold up well to the occasional use I will give them.