There have been many improvements in the compact camera lines over the past few years. Larger sensors, faster focusing, and more controls have all led to a selection of cameras that work smoothly, keep size tiny and are functional with a variety of lenses and accessories to round out your underwater photography experience. Sony and Canon have both given their compact cameras one inch sensors, and greatly improved focus speeds over the cameras of a few years ago. Olympus continued to add features to their cameras while keeping both price and size down.
The A7 III, with its compact and ergonomic design, has been a very popular camera for video recording. The battery life is drastically improved compared to the previous A7 Series cameras, which was a primary complaint of Sony Alpha users and is particularly beneficial for underwater video, as it allows you to shoot for much longer without the need to open the housing. The A7 III also has dual SD card slots, which play an additional role in the maximum allotted time you can record underwater without having to open the housing. The auto-focus during video works very well.