I've returned from my first trip with the Touit Macro, on the Daedalus/ Rocky/ Zabargad/ St John's route, aboard Hurricane. Photos here: https://flic.kr/s/aHsk5kp8ro.
I'm very pleased with the pictures (would welcome feedback!), but I have to say that I'm really disappointed with how the lens works for underwater use. It has a constant focus function that operates independently of the shutter button, and I can't find a way of disabling it. The result is that as you're framing a picture, the lens will start hunting for focus, throwing the frame in and out of blur, and making the task of capturing the moment next-to-impossible. Added to that, the NEX6 doesn't have a thumb focus option, so the only solution is to use the AEL button to switch to manual focus (three button-clicks) to freeze the focus, then move the camera backwards and forwards to get the right focus point, take the pictures, and then switch back to automatic (another three button-clicks) to re-engage focus for the next scene. I was using a SubSee +5, but the focus hunting issue was the same, whether or not the diopter was flipped up.
As a result, I simply can't recommend this lens for underwater use ... and I'm getting closer and closer to switching from Sony to Olympus or upgrading to dSLR. But if I am missing something, or if anyone has a solution to the problem I describe, please let me know to save spending yet more money on shiney new gear!
Thanks for any help.