Alien,
I tried the SMC-1 on the surface (which is all I can do). It displayed the same focus problems my other close-up diopters had: the lens basically hunts past the focal point, than reverses to go back, only to pass it again. It continues to cycle in this manner. Occasionally if the area had really strong contrast points it would lock, but this only happened about 5-10% of the time on areas that focused quickly when there was no diopter on the lens.
The Metabones adapter, on the other hand, would go slightly past the focal point, than reverse directions and VERY SLOWLY approach the contrast point and lock focus. It never went past it more than once in it's calculations. It was very accurate and always locked on first attempt.
I'm not sure why the S90 doesn't work as good as the Metabones in this respect, as it's quick and rock solid by itself with the NEX7. I suspect the lens focus system does not work well with diopters (no logical explanation) and may need a firmware upgrade? Yet, Phil has responded with some success using his Subsee+10 on FF. All I can say is the lens did not reliably work with the Aquatica +10, FIT +5 and SMC-1 on APS-C. Unless I just happen to have a bad copy of the lens or the SMC-1 has to be under water, I would be hesitant to invest in the S90 and new port w/o manual focus until others can show success on the Sony APS-C platform. It's too bad, because the S90 is a 135mm macro on APS-C which is very nice, comparable to the Nikon 105 on DX. It provides considerably more working distance especially with +10 and 15 close-up lens which eat up the distance fast, like the CMC operating in the 12mm range from the port, which needless to say is hardly any room at all for lighting.
I'm keeping my Canon 60 set-up and not looking back until I see more success stories or a firmware upgrade from Sony. My lens is insured, so I will probably send it in for a tune-up and check-out before abandoning the S90 for my NEX7 rig. Plus, Reef Photo told me the Canon 60 lens was what Nauticam based the glass algorithm for the SMC-1 design on, so they work well together, even when using a Metabones adapter. My MB adapter has Firmware 31 by the way which works good.
Marsh