A6000, what else do I need to start?

DigiPainter wrote:

I forgot totally about wet lenses, oh boy a new thing to learn haha.
So dont throw my 16-50mm away? Honestly Im not happy with the photos from it. Just not sharp enough, I think thats why i want primes like you 90mm macro, and the ronkinon 12mm.

It's a matter of approach, and there are pros and cons to each. 16-50mm + wet lenses will give you the flexibility to shoot macro and wide angle on a single dive, but the wet wide lenses will give you fisheye distortion which works for many shots but ruins others, and they're too small to shoot over/under splits. Likewise, diopters will limit your focus distance window in both directions, as I already mentioned. There is also the matter of mindset - if you're poring over the reef, scanning for tiny shrimp or pipefish, you're liable to miss a great potential wide-angle coral composition, and vice-versa - while setting up that great wide-angle shot, it's quite unlikely you'll spot that camouflaged pygmy seahorse.

As far as sharpness, a lot of conventional wisdom from land photography flies right out the window once you submerge. The port and its water/air boundaries act as an additional lens element, completely invalidating dry land test results. Aside from a very few exceptions, camera lenses are not built to function underwater, and water itself affects image quality to an extent that dwarfs the difference between various lenses. The humble 28-70mm full-frame kit lenses easily outperform $2000+ 12-24mm/16-35mm setups when placed behind a Nauticam WACP, which is specifically engineered to compensate for the differences in shooting underwater - but WACP costs almost four thousand dollars, and its internals feature some of the largest lens elements produced for the mainstream camera industry; similar to those inside $10k super telephotos.

Is the sony 90mm really awesome?

It's a great lens to use in clear tropical water. If you're diving in temperate waters, where visibility is less, its working distance may prove excessive, particularly when mounted on a crop sensor camera.