Sony a9 Mirrorless Camera Preview

Sony has announced flagship full frame camera body designed for speed, with 24MP sensor and 20fps burst shooting
By Brent Durand

Sony has just announced a new flagship full frame mirrorless camera at an event in New York City. The Sony a9 boasts a 24MP CMOS sensor and 20fps burst, with big claims that aim to create strong competition with other cameras in the pro sports category - namely the Canon 1D X Mk II and Nikon D5. The camera looks sexy with the new Sony FE 100-400mm f/4.5-5.6 GM OSS telephoto zoom lens attached.

The Sony a9 incorporates a full-frame stacked 24.2MP CMOS sensor paired with an upgraded BIONZ X image processor. 20fps shooting is possible without any blackouts between frames (blackouts break up autofocus on DSLRs due the drop of the mechanical shutter). The electronic viewfinder is the best in the Sony mirrorless camera lineup and the autofocus is incredibly fast, focusing (and calculating exposure) at up to 60 times per second.

The electronic shutter means no mechanical shutter vibration - something that macro and supermacro shooters will cherish.

Battery life, a nagging issue with those that shoot Sony underwater, has been improved 2.2x from Sony's previous full-frame camera models (a7 II series). Topside shooters can also use a grip for expanded battery life.

Video image quality is very impressive, delivering 3840x2160 4K video from full-pixel 6K readout with no pixel-binning.

4D autofocus, 5-axis image stabilization, dual SD media slots and other features are just the cherries on top with the Sony a9's impressive spec list. Drooling yet? I am!

Availability:  Pre-orders start April 21, 2017

Estimated Price:  $4,499 USD


Sony a9 Camera Specs

  • Full-frame 24.2MP stacked CMOS sensor with integral memory
  • BIONZ X processing engine
  • Continuous shooting up to 20fps with AE/AF tracking
  • 693-point wide-area phase detection AF
  • 5-axis image stabilization (up to 5 stops)
  • 4K video recording with no pixel-binning (oversampling at 6K full-pixel readout)
  • ISO 100 - 51200 (mechanical shutter), ISO 100 - 25600 (electronic shutter)
  • Viewfinder: 1.3cm electronic 3686k-dot Quad-VGA OLED Tru-Finder
  • Dual SD card slots. (lower slot UHS-II)
  • Sony E-mount lens compatibility
  • Dimensions (WxHxD): 126.9mm x 95.6mm x 63.0mm  /  5 x 3 7/8 x 2 1/2 inches
  • Weight (with battery & SD card): 673g / 1lb 7.7 oz

Sony a9 Recommended Lenses

Sony offers a nice lens selection for underwater photographers shooting the full-frame a9, both for photo and video.


Macro Lenses

  • Sony FE 90mm F2.8 Macro - The best option for Sony macro and supermacro shooters.

  • Sony 50mm F2.8 Macro - This lens is more of a mid-range when shot on full-frame, ideal for larger (yet still not wide-angle) subjects like big frogfish and stingrays.

  • Canon EF 100mm F2.8 Macro with Metabones adapter - This is the best macro lens out there but we haven't tested it with the adapter, so expect significant performance loss.


Wide-Angle Lenses

  • Sony FE 16-35mm f/2.8 ZA SSM II Vario-Sonnar T* - A fast, pro-level ide-angle lens for situations where fisheye field of view is too large or warped and when macro is too narrow.

  • Sony Vario-Tessar T* FE 16-35mm f/4 OSS Lens - A great wide-angle lens choice for those who don't want to buy the more expensive f/2.8 version.

  • Canon EF 16-35mm f/2.8 II or f/4 with Metabones adapter - These are Canon wide-angle staples, and great if you're switching over, but if you're starting new we recommend the native Sony wide-angle lenses.


Fisheye Lenses


Thoughts for Underwater Photo and Video

The Sony a9 is going to be a fantastic camera underwater, although it's more camera than most shooters will need. Many of the key differences between the a9 and the a7R II involve high-speed autofocus, burst shooting and fast processing speed that only those currently pushing those limits will notice.

Keep in mind that the Sony a9 has both a mechanical and mirrorless shutter, so the body size is going to be closer to that of a DSLR than that of a small mirrorless setup.

Personally, I find the Achilles heel of the Sony system underwater to be the 90mm macro lens. I used this lens with the Sony a6300 in Lembeh Straight while leading a workshop last September, and the autofocus / lens combo simply didn't compete with the Canon 5D Mark III and Canon 100mm macro setup I owned in 2012-15. Granted, the Sony a9 has some serious AF upgrades, but then so do the competitors - the 5D Mk IV and Nikon D810.

There are two reasons I would choose the Sony a9 over the Sony a7R / a7R II and DSLR competitors:

Video: The Sony a9 condenses full-pixel image into 4K video with no pixel-binning. Bottom line is high-quality video with beautiful color tones, contrast and sharpness. The full-frame sensor will likely deliver more dynamic range and better image quality than even the hyped up Panasonic GH5. That said, we won't know for sure until we test it, since the GH5 records 4K 4:2:2 10bit (1024 RGB color levels) while the Sony a9 only records 4K at 4:2:2 8bit (256 RGB color levels). 

High-speed shooting:  This camera should excel for topside shooting with better AF tracking, 693 AF points, 20fps burst and the quick integral processing of the new stacked CMOS sensor. Naturally, this screams sports, however there are some applications underwater where this will prove invaluable. This includes ambient light wide-angle with fast subjects like sea lions and dolphins, as well as macro behavior shooting under constant lighting.

So what's the move? Call or email the experts at Bluewater Photo to further discuss your camera options.


Sony a9 Underwater Housings

We expect to see the first housings ship within 3-5 weeks of the camera release. Expect Ikelite and Nauticam to be first, followed by Aquatica and Sea & Sea in following weeks. For pre-orders and to be first to know about these housings, email Bluewater Photo and they'll keep you up to date.


Brent Durand is a weekend wanderer and story teller from California.

Brent is an avid diver and adventure photographer, and shoots underwater any time he can get hands on a camera system. He can be reached at

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