Sony a6100 Underwater: Initial Thoughts

Sony a6100 Underwater: Initial Thoughts

September 18th, 2019

The Sony a6100 is the new budget model in Sony’s popular APS-C sensor mirrorless line of camera. Its announcement is just another in an already prolific year for Sony which featured the release of the Sony a6400, Sony a7R IV, Sony RX100 VII, and the Sony a6600. While the camera is really only an upgrade to the Sony a6000 and performs below recent models like the Sony a6400 and a6600, it is a very viable option for anyone looking for a cropped sensor mirrorless camera on a budget. If you are already invested in another camera in the Sony a6000 line, then this camera might not be worth the switch. However, if you’re looking for a capable mid-range mirrorless camera at a low price point, this might just be the best option out there!

The additional features available in the camera are sure to be welcomed by underwater photographers. Sony has a reputation for outdoing other companies by introducing new technologies and anchoring them into every subsequent model – whereas Canon or Nikon might drop features in their mid or low range cameras. 


U.S. MSRP Sony a6100: $750


Sony a6100 underwater camera review


Jump to Section:


Sony a6100 Specs   |   Sony a6100 vs Sony a6000  |   Key Features

a6100 for Underwater Photo and Video  |   Best Lenses  |   Underwater Housings

Sample Images   |   Conclusions


Purchase the Sony A6100 Camera, Housing, and Packages at Bluewater Photo:

 Sony a6100 Camera Body

Ikelite Sony a6100 Underwater Housing

Fantasea Sony a6100 Underwater Housing



Sony a6100 Camera Specifications 

24.2 megapixel APS-C CMOS Sensor

0.02 second autofocus acquisition – contrast-phase detect hybrid AF system

425 phase detection AF points and an equal number of contrast detect AF points

Real time AF tracking, including Animal Eye AF

Native ISO Range of 100-32000

1/160 sec sync speed with flash

380 shot battery life

1.0 cm electronic viewfinder (limited underwater application)

4K @30fps video, 1080p @ 120fps

No picture profiles

No 5 axis in-body image-stabilization

Supports E-Mount lenses

4.75” X 2.75” X 2.375”

Weight: 396 grams

Key Upgrades from the Sony a6000

Processing: Sony a6100 sensor has a front-end LSI chip for better processing and a new BIONZ X processor

Sony a6100 outputs in 14-bit RAW

Sony a6100 has a slightly expanded ISO range (ISO 100-32000, up from ISO 100-25600)

Updated AF system: 425 contrast and 425 phase detect AF points. Real time AF tracking, animal eye AF

Faster focus acquisition

Massive video upgrade from Sony a6000: The a6100 can now shoot 4K @30p whereas the a6000 could only shoot 1080p @ 60 fps

Touch LCD

Built-in intervalometer


Sony a6100 Vs Sony a6000

The Sony a6600 has been a viable camera for the last five years, and even with these updates remains so today. However, the a6100 is certainly the better option. The largest differences between the two cameras is the processing power, video system, and AF system. The a6100 is equipped with a front-end LSI chip and a BIONZ X processor for quicker processing. 

Like the Sony a6400, the a6100 has been updated with Sony’s top of the line autofocus system. In addition to the large increase in the number of contrast detect AF points, the a6600 features updated AF tracking, including animal eye AF.

Video on the a6100 has been modernized shooting the 4K @ 30p video standard that is now ubiquitous today. Unfortunately, the a6100 does not offer any Log picture profiles which are used by video shooters for capturing better dynamic range. This could be a deal breaker for underwater videographers who want to color grade their footage. 

Sony a6600 Key Features

Body and Build

The Sony a6100 is built very similar to other cameras in the a6000 line. The body is solid, compact, and weather-sealed for moisture and dust, adding an extra layer of protection underwater. The menu system is going to be a little clunky as a Sony menu, but not something that takes too much learning to get used to.

Image Quality

As with other cameras in the a6000 line, the image quality on this camera is excellent. An aps-c sensor is going to yield more detail than popular and smaller four-thirds sensor mirrorless cameras. It’s a great alternative if you don’t want to invest in full frame, but perhaps this camera is getting a little to close to the price of the Sony a7III

Because the ISO range was expanded from the A6000, we are hoping low light performance and dynamic range will be improved from an already great system. But only our underwater tests will be able to confirm this. 

Auto Focus and Autofocus Tracking

The Sony a6100’s autofocus is one of the best topside AF systems in the world, but Sony cameras often perform differently underwater. One of the most notable improvements from the Sony a6000 is the improved AF tracking including the exciting new animal eye AF. One of the often followed “rules” of underwater photography is to have your subject’s eyes in focus. Theoretically, AF tracking should make keeping the eyes in focus and easy endeavor – even with moving subjects. When we tried this on the a6400 we had successful results, but the camera didn’t always identify an eye. That being said, we were able to save some shots by using the function – especially with macro shots

Sony a6100 Best Lenses



  • Sony 50mm f/2.8 Macro Lens (SEL50M28):  A great choice for all Sony APS-C sensors, offering a wider field of view for larger macro subjects and fish portraits.


Standard / Mid-Range






Recommended Topside Sony Lenses

While we love to dive with Sony lenses, they perform to the same high standard on dry land too. If you're considering adding to your topside kit bag, look through the options below.


  • Sony 600mm F4 FE GM OSS - Ideal for capturing fast-moving subjects from a distance. This top-of-the-line telephoto lens is everything you'd expect from a flagship product.


  • Sony 12-24mm F4 FE Wide-Angle - A high-quality wide-angle zoom that's perfect for landscapes, interiors and other times when the goal is to get as much in the frame as possible.

Sony a6100 Underwater Housings

A wide range of housing options for the a6100 will be available from most major underwater housing manufacturers. We anticipate housings from Ikelite, Fantasea, Nauticam, and more!

Sony a6400 Sample Underwater Images

The Sony a6400 camera is the closest to the Sony a6100 that we've tested. In fact, the image quality on the Sony a6100 should be about the same. Until underwater housings come out for the Sony a6100, check out these sample image from the a6400. 

Sony a6400 camera underwater


The Sony a6000 camera line has always been a unique option for underwater photographers in that it offers an excellent aps-c mirrorless option with housings from many manufacturers at a low price point. For photographers looking for pro and semi-pro image quality at an affordable price, this is the line of cameras most underwater photographers look at. The a6100 is certainly what underwater photographers are looking for when considering their budget, unlike the more expensive Sony a6600. The Sony a6100 is certainly a nice upgrade to the Sony a6000 featuring one of the world’s top autofocus systems, beautiful dynamic range, and 24.2 MP of APS-C level detail.

Purchase the Sony A6100 Camera, Housing, and Packages at Bluewater Photo:

 Sony a6100 Camera Body

Ikelite Sony a6100 Underwater Housing

Fantasea Sony a6100 Underwater Housing



We make awesome trips possible!

Read more

Educational Videos and Articles

Read more

Find the right gear with our Buyer's Guides

Read more

Win a free trip by joining our newsletter

Ask us anything!