Contributed by David Haas
Canon's answer to the Sony Cyber-shot RX100 Mark III is no slouch in specs. But how does it hold up underwater? Photo pro, Ikelite guru, and Authorized Dealer, David Haas, spent a week in Grand Cayman putting it through the paces.
The most obvious difference between the Canon PowerShot G7X and the Sony Cyber-shot RX100 Mark III is the lens. Even RX100 disciples admit that the 24-70mm equivalent zoom range is fairly limited for a compact camera. Canon boosts this up to a 24-100mm. This is just about the perfect zoom range for underwater and makes it great for macro right out of the box.
Long, telephoto zoom lenses are great for shooting far-away subjects on the surface, but underwater they actually limit us. A long zoom lens requires a long port, and long ports are the enemy of external "wet" lenses. So mid-range zooms ranges like 24-100mm provide great versatility underwater while allowing external lenses to be effective. A wide angle lens attached to the G7X will show a porthole effect at 24mm, which can be left in for creative effect or cropped out to maintain maximum resolution and clarity. Vignetting goes away around the 35mm equivalent mark and provides a wider angle of coverage than the native lens.
The Canon's lens is also overall brighter across its zoom range than the Sony competitor. An astounding maximum aperture of f/1.8 at 25mm—and f/2.8 at 100mm—allows you to capture more light. Great low-light performance is important underwater, as the sun's light is quickly absorbed as it passes through water, making shooting at depth similar to shooting in a dimly lit room.
The RX100 Mark III is still the choice if video is your #1 focus. But if you're really looking for a camera that does both stills and video well underwater, then you won't be disappointed.
Manual exposure controls are essential in a high-end point-and-shoot. Canon provides the now-expected front and rear control wheels to quickly change the most common settings in between shots (for example, shutter speed and aperture in Manual mode). New to the GX7, both dial controls are gear-driven in the housing. This brings them into thumb and index finger reach of your right hand, making exposure bracketing a breeze.
On the surface Canon gains a slight edge over Sony for ergonomics, with larger buttons on the back of the camera that are a bit easier on big thumbs.
Unlike the other cameras in Canon's G-series, the G7X supports TTL flash in the camera's Manual mode. This means that you won't be limited to Shutter or Aperture priority when shooting the AF35 and other strobes which support slave TTL.
If you're really ready to take full control, you can add DS51 or DS161 strobes with Fiber Optic Adapter(s) for a super-fast and powerful strobe set-up. DS strobes are the best choice if you're using this as a back-up to a DSLR, or considering moving into a mirrorless camera system in the future. All flash filled photos in this article and the supporting photo gallery were shot with dual DS51s.
Unique polycarbonate construction allows the camera's built-in WiFi feature to penetrate the housing walls. You can be reviewing photos on your iPhone or iPad before the boat gets back for lunch!
If you want a Pro-level compact system, that's fantastic for travel, this is the ticket! Check out the supporting photo gallery below for a full set of images with and without flash, from macro to wide angle.