There are some cameras that were made specifically for being used underwater for example the SeaLife DC1400. But, just from reading the mixed bag of customer reviews on Amazon, it’s clear that it’s not the best underwater camera for scuba diving. The buttons stick, the flash doesn’t work, the shutter delay is insanely slow… just a few of the problems you can run into.
Housings are a topic that deserves a detailed post of their own and you’ll see one here on The Adventure Junkies in the future. But, until then let me briefly talk about choosing an underwater housing. Also, you can read Basics of Underwater Photography: Choosing Cameras & Housings which goes into more detail about housings as well as ports, lenses and accessories.

Another highly sought-after, and relatively exclusive, feature within the video camera realm is the ability to record in RAW or ProRes. These are uncompressed formats that maximize the information gathered by the sensor and provide you with extended flexibility when it comes to color grading and post-processing. As mentioned, this feature is quite an exclusive one and only available in a select few cameras on the market with good processors (again, excluding high-end cinema systems). Some select cameras can record in ProRes Raw with an Atomos Ninja V external recorder. Nauticam offers a housing for the Ninja V for use with your underwater system.
Then there's resolution and video quality. You'll want a camera that can record in 4K for sure. The top-end models from DJI and GoPro offer 60fps 4K with digital stabilization that's absolutely incredible. They're also not limited to ultra-wide views; you can set a narrower angle to remove lens distortion, making them solid choices for vlogging and travel logs. 

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