Alas, I must report that these tubes are completely unsuitable for their intended use. The finish is beautiful, but the fit is horrible. I expected flimsy and fiddly. That much was correct -- first impression out of the box was that the three-part tube was quite wiggly due to looseness in the bayonet fittings. Nonetheless, I mounted the full set of three tubes between lens and camera. At first I was pleased to see that, while mechanically wiggly, the electronic connections did seem to be working. That pleasure disappeared when I took the set apart, tried the rings individually, and discovered that two of the three rings were extraordinarily difficult to get inserted into my camera and the locking pin would not engage in any position. Likewise two of the three rings were difficult to get onto my lens, and would not lock properly there either. Apparently by luck, the only configuration that worked sort of OK was the full set, assembled in the order in which they were shipped. On re-testing, I found that one tube (the long one) did work OK by itself, though oddly, it did not when I tried it earlier.
The difficulty appears to be just ridiculously bad tolerances in the machining. I cannot see any definite reason why the rings are difficult to mount and won't lock.
But in any case, these are going into my otherwise almost empty collection of aesthetically attractive but functionally useless junk. They're not worth returning, and I certainly wouldn't give them away to anybody who might try to actually use them, but it pains me to throw away anything that looks so well made.
--Rik
