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Sony A9 III Underwater: Review & Initial Thoughts

Sony A9 III Underwater: Review & Initial Thoughts

Posted by Nirupam Nigam on November 12th, 2023

Sony has once again revolutionized underwater photography. With the Sony A9 III the coveted, long awaited, and seemingly unattainable "global shutter" is here. For years, the idea that every pixel on a sensor could be recorded and sent to the processor instantaneously felt more like a thought-experiment than a possibility. What would such a shutter mechanism look like for underwater photography? Well now we know... and it's game-changing. 

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Check out our guide to the best Sony A9 III underwater housings

The World's First Global Shutter Camera

Flash Sync Speed of 1/80,000

First off, the global shutter on the freshly announced A9III allows for flash sync speeds equal to the maximum shutter speed on the camera - 1/80,000 of a second. Essentially, you can now use your strobes at any shutter speed. Considering that until now, most full frame cameras could not shoot higher than 1/250 with strobes, the A9III represents a whole new dimension of creativity. 

In underwater photography, the shutter speed on your camera is used to control the exposure of the ambient light (e.g., the background) of your image. Being able to shoot at much higher shutter speeds allows you to shoot in shallow, clear water, directly into the sun. Because your artificial light from your strobes is not affected by shutter speed, your strobe exposures should remain the same while having even more control over your background. It will be easier to capture black background macro photos as well. That said, there is a certain point where the time it takes for your strobe to fire will be eclipsed by the fast shutter speed. This is sure to vary by strobe brand and it will be interesting to test at which point strobe power will decrease because the shutter is too fast. 

No Rolling Shutter

With an instantaneous, global shutter, the phenomenon of rolling shutter is eliminated in the A9 III. Roller shutter is the process where an image warps because the sensor is read out top to bottom when taking a photo. Action photos will no longer have warpy artifacts when shooting with the electronic shutter. For action photographers, particularly ambient light action photographers, that want to take advantage of the insanely fast 120 fps burst shooting speeds of the A9 III, this camera is a dream. It will be easy to shoot quick pelagic subjects and any speed and not worry about rolling shutter with fast subjects. 

Rolling shutter also helps make movement in video less warpy and "jello-y" when panning. Underwater video shooters should be happy with this development as well. 

Finally, a lack of rolling shutter has also eliminated issues with banding while taking photos under incandescent light. While this is not a benefit for underwater shooters, it is an excellent feature. 

120: The Magic Number

With a 24.6 stacked CMOS full-frame sensor, the A9 III is designed for speed beyond the global shutter. Because the sensor is stacked, reducing processing times, the camera is capable of 120 autofocus calculations per second as well as 120 frames per second burst shooting (14-bit RAW files). This makes the A9 III the fastest focusing and shooting full-frame camera in the world. Although most underwater strobes would not be able to keep up with these speeds, the A9 III does open up a new dimension of autofocus tracking and burst shooting capability. Action photographers will not be able to find a better camera on the market, likely for years to come. 

Concerns About Dynamic Range

As with any new technology, there are certain drawbacks associated with the Sony A9 III. The stacked sensor design will likely reduce dynamic range. The native ISO of 250 on the A9 III indicates this as well. However, we will not be able to evaluate whether or not this will be the case until we have the RAW files in-hand from production models. 

4K/120p Recording

While the dynamic range limitations might not be great for video shooting, the A9 III should still be a very capable video camera with the major highlight being the lack of rolling shutter. The camera is capable of capturing 4K/120p video with the full width of the sensor and 4K/60p oversampled from 6K for more detail.

Top Sony A9 III Specifications

  • 24.6 megapixel stacked full-frame CMOS sensor
  • First full-frame camera with a global shutter
  • 1/80000 max shutter speed and flash sync speed
  • 120 autofocus calculations per second
  • 120 fps 14-bit RAW burst shooting
  • 4K/120p recording with full width of the sensor
  • 4K/60p recording oversampled from 6K for more detail
  • -5 EV lowlight autofocus sensitivity
  • Electronic shutter only
  • 8 stops of 5-axis in-body image-stabilization
  • Weight: 617 grams
  • Size: 136.1 x 96.9 x 72.8mm

Sony A9 III Underwater Housings

The Sony A9 III will be available to consumers February 21, 2024. With such an exciting camera housing manufacturers will certainly be working quickly to release a housing and we expect housings to become available by the end of March. Though Nauticam and Ikelite typically announce housings first, we expect housings from most manufacturers including AquaticaSea & Sea, and Marelux


Although the Sony A9 III is not a camera for the general consumer - after all, it clocks in at $5999.99 - it is a marvel of engineer. The jump Sony has made to the global shutter will likely be as impactful to underwater photography as the jump from DSLR to mirrorless cameras. The newfound capability of a shutter and sync speed maxing out at 1/80000 as well as recent improvements in strobe technology results in incredible control of ambient and artificial light. Incredibly shallow sunball photos and beautiful black backgrounds will be easily attainable. The only potential limitations could be the duration of the flash coming from the strobe itself - an aspect of strobe engineering that had not been a limiting factor in the past. 

The global shutter has also opened the door to incredibly fast autofocus refresh rates as well as incredibly fast burst shooting. At 120 fps, it will be almost impossible to miss action. With no rolling shutter, the A9 III is the ultimate action camera for baitball and pelagic shooting. 

And though we may see limitations in dynamic range at first, this is Sony's opening bid at global shutter. In years to come this technology will be sure to trickle down to consumer-grade cameras with improvements to dynamic range. One thing is certain, it's an exciting time to be an underwater photographer. 

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