Hi CCRphoto I've just gone down a similar path myself and the criteria you outline are pretty common ones. A good number of members - especially we, errr, more aging ones, are looking to "downsize" and have less gear to carry. I gave up on FF camera bodies (Nikon D800) in 2017 as having to lug a 230mm domeport - or some sort of big glass wetlens - was becoming a pain. I settled on the D500 APS-C system which, generally, allowed for slightly smaller bits of gear. I lost all that recently so had to rebuild from scratch. I'm not at all persuaded by the marketing charms of needing FF and high megapixel camera bodies for underwater. I sell lots of images and no-one has ever grumbled that they are not produced by a FF camera. I reckon 20MB is plenty unless you want massive prints or are shooting purely commercial imagery. Topside is different (no ports!!). Listening to folks here, I came to the conclusion that the OM System plus Nauticam was the way to go. The OM System is compact and light-weight but still has 20+MB sensor. Nauticam has become, perhaps, the system most used by people who want aluminium housings, providing good support and innovative products which are continually developed. I've now acquired a housing, 45-degree viewfinder, arms and clamps, N85 WA and macro ports, an OM-1ii camera body, and Panasonic 8mm FE and Olympus 60mm macro lenses. The housing is smaller, slightly, than the (Subal) D500 housing, the camera and lenses significantly smaller than FF or APS-C (almost like back to the OM-1 and OM-2 days of the 1970s). But put the whole package together, add two Retra strobes, and weight and volume wise, they are not that much different to my APS-C system. But then maybe I just need to give up trying to pack everything into a heavy Pelican 1510 case! Fibre optic initiation: yep, a definite must. I don't use TTL either but do want HSS. That rules out the Nauticam trigger. But both Turtle and UWT have compact triggers which do the trick nicely. Both are quality products with very good support. I can recommend either. Familiarity of controls: well if you've never stepped into digital, there is a big difference in the ability to customise controls. Effectively the camera body is a mini computer which you can customise to your heart's content. I doubt I scrape 10% of what they can truly do. I set mine to Manual exposure, AF in one form or another, shoot RAW, Auto WB and very rarely, burst shots (without strobes for, eg dolphins). The OM will let you set up a number of, effectively, customised setting folders so you a switch easily between one setup and another. Think one set of settings for macro, one for WA controlled by the flick of a switch. But there is sure a learning curve - even switching from Nikon to OM! But the basic "photo references" remain, eg, ISO, Shutter speed, Aperture etc. And, the most important thing, composition - which is what it is truly all about - is not digital! That hasn't changed at all. Hope this helps a bit! Good luck with it. They are not easy decisions for sure.
