Summary: Given the relatively high price, this extension tube does not couple as firmly as expected to standard Canon EF lenses. There is some play in the bayonet mount. But it seals adequately against stray light, and of course has all the electro-mechanical connections.
Excerpt: I use this with a Canon 24-70mm F2.8 II, at a focal length of 70mm. It turns the lens into a macro lens which is what I was looking for. You must set the lens on manual focus. The extension tube is just a tube. It has no glass. Its build quality is excellent.
Pros: Consistent Output, Durable, Easily Interchangeable, Lightweight, Rugged, Strong Construction
Decent build quality, does what it's supposed to do.
Joseph, B&H Photo
4 May 2015
Excerpt: The best thing about this extension tube is the fact that you still get full control over your lens through the camera controls, unlike the cheaper tubes. Why would I get this over a dedicated Macro Lens? It's cheap and it doesn't take up much room in your camera bag.
Pros: Consistent Output, Durable, Easily Interchangeable, Rugged, Strong Construction