Sony a6400 Underwater Video

June 19th, 2019

One of the major highlights of the Sony a6400 is its underwater video capability. In fact, the a6400's video is at a standard that is often featured in professional-level cameras. Considering the price-point, the a6400 is one of the best options on the market for anyone looking to get into underwater video. The main reason for this is video quality. Yes, a lot of cameras offer 4K video, but not all 4K video is made equal. The a6400 is gifted with a BIONZ X processor capable of recording large amounts of data quickly. This means the Sony a6400 can utilize every pixel on its sensor by capturing video in 6K and then downsampling it 4K, preserving every detail from its sensor. Other competing cameras would instead take 4K by cropping or pixel binning, which degrades quality.

Moreover, Sony has updated the a6400 to have better color rendering when capturing video. It's not quite the level of a Canon or Nikon professional system like the Canon EOS R or Nikon Z6, but it's close. The a6400 has also been cleverly programmed with an animal eye autofocus tracking mode. This is huge for underwater videographers. You can now track fish, octopus, and really anything with an eye without having to worry about losing focus. When it found the eye in our tests, it worked very well.

The downsides with the Sony a6400's video capability are apparent, but easy to work around. The Sony a6400 does lack in-body image-stabilization. Although many of Sony's lenses are stabilized, it would have been nice to see even more stable video. The second downside is that the rolling shutter on the a6400 is poor when compared to the GH5. That being said, both of these issues can be remedied by capturing video as still as possible - something most underwater videographers strive for anyway. For anyone looking for the extra help of in-body image-stabilization, the Sony a6500 offers this.

Story Behind the Video:

This video was taken over the course of seven dives in the Pacific Northwest during a period of calm tides. I was able to visit some of the best sites in the region that normally would be inaccessible due to strong currents. These sites have a plethora of invertebrate life that thrive on nutrients brought by currents that can reach up to 14 knots! Because all the diving I do is from shore, I must time my dives with the tides so that I only dive on slack. This can make for a wild and difficult ride when shooting video if you don’t get the timing quite right.

You’ll notice that many of the clips in the video feature large walls covered with a rainbow blanket of invertebrates – especially anemones. The sites off of Whidbey Island, Washington were the most interesting to shoot, and I tried to capture as much color as I could with by Venom 60 RGB video light and Symbiosis SS2 strobe. When panning, I had to be careful not to move too quickly in the current. Otherwise, I needed to find a good spot to anchor myself and position my lights for interesting angles with good shadows.

The wolf eels in the beginning of the video were also a joy to shoot. Many of us local divers know some sites in the Tacoma, Washington area that harbor a number of very friendly wolf eels. Wolf eels are a little like cats. They’re cautious, but sometimes they’re curious and might come out to let you play. On the day I shot this video, they were pretty happy to come out and ogle at the divers that were ogling them. Their quick movements made for interesting video. The orangish wolf eel is a sub adult – likely a female. The larger gray wolf eel is a large male that was going back into its den to join its female mate. Interested in wolf eels? Check out this article about photographing wolf eels.

The macro clips were the most difficult but rewarding clips to capture. The a6400 is truly a marvel when it comes to capturing details in video. This is especially apparent when you look at the details of the eyes and skin in the macro clips of the sculpin and octopus. Although autofocus was a little more finicky in macro clips, I still managed to get some amazing video of a small red octopus traveling down a deep, muddy slope on a night dive with almost no visibility. Although it wasn’t the best diving conditions, I was able to make use of the situation.

Sony A6400 Camera Specifications:

24.2 MP APS-C Exmor CMOS Sensor
Latest BIONZ X Processor
4K video @ 30fps - downsampled from 6K
No pixel binning or cropping at 4K
1080p video @ 120 fps
Now offering hybrid log gamma (HLG), S-Log2, S-Log3 picture profiles
No video recording time limit
Lightning quick autofocus acquisition of 0.02 sec
425 phase detection contrast-detection AF points covering approximately 84% of image area
Real-time autofocus tracking for object tracking
High-speed continuous shooting at up to 11 fps
Improved buffer size for JPEG and RAW
Advanced High-Resolution 4K with Fast Hybrid Autofocus
Interval recording for time-lapse videos
180-degree fully tiltable LCD touch screen