The more I think about it the more I agree that a crop sensor would be better for someone just getting into underwater photography. the size of dome ports you need for a full frame is definitely a big consideration as well and a big piece of equipment to lug around. the Sony a6500 looks like a nice little camera that I would imagine would be pretty good and compact. There's quite a bit of older Sony equipment for some great deals. I've only used a Sony RX100 V with a Nauticam wet wide angle lens and was able to get some pretty decent shots. Sony makes many of the camera sensors even for other manufactures so I'm sure they're camera sensor are pretty good. I'm wondering if anyone has any experience with the older NEX5 or NEX7 cameras underwater. They have a crop sensor and can be found for pretty cheap. There's a Nauticam housing for NEX5 on eBay for $400 and the camera is only around $100 through eBay as well. Personally I would use the 50mm f2.8 macro that costs $200. required N85 to N120 port adaptor is $480 and the macro port is $360. So what seems like a good deal for a housing that only costs $400 now just turned into $1,540. The more I look at the compact Sony crop sensor the more it entices me. From the stats, they seem like pretty good cameras. I wish I could say from my own experience whether they were any good or not. I also found a full kit for a Sony NEX5n on eBay with 2 ports and 2 lenses. You still may need to get some other ports and a macro lens to shoot close up, but this kit would get you in the water. for much less than it would've been separately. The reviews don't look good for what yo could get today. the NEX5 is probably not a great option for what's currently available.
The Fuji XT-2 would be a great camera underwater on land and in the water with outstanding color rendition. My father has been doing photography for over 45 years and has the XT-1 and loves it. To get anything Fuji though would have to be purchased new which puts anything from them way outside the price range for this discussion. But now we can rule them out.
If you go with Sony, here is a good article about different macro lenses available with comparison photos. Pretty good article.
Edited by Fruitographer, 13 June 2018 - 09:54 PM.