I take this extension tubes along with two popular macro lenses, the EF 100mm f / 2.8 L IS USM and the EF-S 60mm f / 2.8 to two cameras, the EOS 5D III and the 7D. When purchasing I consciously decided against cheap rings in the 20 + x-Euro-class and do not regret it. These rings transferred here really all electronic lens features not only in theory but also in practice properly. With the good AF systems of the two cameras I therefore remains the possibility to get hand-held photography. This is important if you do not stand here or the object is to move.
Even with all three stacked rings and corresponding razor-thin depth of field usable images are already managed me (of course, with some luck, patience and more misses). Of course, the autofocus will be noticeably slower.
Also mechanically convince these rings. So there are 5 star.
