Product Reviews

Sony RX100 III Underwater With Fantasea Housing Review

I recently got a chance to take two of the leading high-end compact cameras in the market for a few days of diving in the Red Sea, along with Fantasea housings and a complete set of accessories. Both the Sony RX100 III and the Canon G7X are top performers and incredibly popular among underwater photographers since their release a few months ago.

In this post I will cover the Sony RX100 III in the Fantasea FRX100III housing.

Click here for the Canon G7X review.

The Sony RX100 III Camera

Almost any underwater photographer has already heard something about Sony’s RX100 series. Usually very good things. Since the release of the first RX100, reviews have been off the charts and both topside and underwater photographers have gone crazy over this small and capable camera. Even 3 models down the line, Sony continues to lead the market and creates a better product every time, as technology advances. We are already seeing the release of the 4th camera in this series coming soon (Sony RX100 IV).


Here is an overview of some of the great features of the RX100 III:

  • 1″ 20.1 MP Exmor R® sensor for extreme low-light shots
  • Bright F1.8 Zeiss Vario-Sonnar T* lens (24-70mm)
  • Built-in SVGA OLED viewfinder w/ZEISS T* coating
  • Selfie-ready multi-angle 3″ Xtra Fine LCD™ display
  • Versatile shooting w/ XAVC S1, AVCHD and MP4 formats
  • Built-in ND filter for wider-ranging photographic expression
  • HDMI clear output for uncompressed video recordings
  • P/A/S/M operating modes with smooth precise control ring
  • Simple connectivity to smartphones via Wi-Fi® w/NFC

All these features packed in a tiny compact camera = Perfect for underwater!

I especially liked how fast the AF works on this camera. The AF speed is more comparable to that of DSLR’s, rather than other compacts I have tried. That’s incredibly important for underwater subjects, especially when shooting macro.The narrower zoom range (70mm instead of 100mm with competitors) is actually easily compensated for with plenty of Megapixels, so that with quick cropping in post processing,  you can get that extra focal range needed and preserve the same quality and sharpness, even for large prints.

The Zeiss lens is extremely sharp and you will see in the sample images below the impressive amount of detail you can get with it.

The Fantasea FRX100III Housing

Get it here

Fantasea’s high-end polycarbonate housings have already become famous in the industry for their sleek design, excellent ergonomics, reliable double O-ring seal and extensive array of accessories.

The FRX100III housing features the same great qualities we recgonize from previous housings, with the exception of a different port shape. To better accommodate the optics of this camera, Fantasea implemented an innovative 55mm thread, along with a new array of accessories designed for this port including the BigEye, RedEye, PinkEye and more. The housing also comes with a free 55mm to 67mm adapter ring to accommodate any standard 67mm filter / lens.

Setting up the camera in the housing is super easy and doesn’t require anything else besides the camera. Simply slide it in and close it with a secure rotating locking mechanism. You will find that the housing allows access to all of the camera’s controls, and handling the camera inside the housing is even more intuitive and comfortable than using the camera itself. All of the controls are clearly labeled and everything is within reach.

Fantasea FRX100 III Housing for the Sony RX100 III
Fantasea FRX100 III Housing for the Sony RX100 III

You can choose to use the internal popup flash using the included diffuser, which would be a nice solution for closeup shots, or add an external strobe which would connect to the housing with a fiber optic cable to one of the two available connectors on the front of the housing. Using a special removable plate, the internal flash will be completely blocked when using an external strobe so that it won’t interfere with your lighting and create unwanted backscatter.

A metal coldshoe is positioned on the top of the housing to easily mount accessories such as a focus light or a GoPro. Across the housing you can find several securing points for securing your accessories to the housing. On the bottom the housing is equipped with 3 standard 1/4″-20 holes for mounting on trays and tripods.

In addition to the double O-Ring seal, Fantasea have included a leak detector inside their housings, triggered by a striped sensor located on the very bottom of the housing. With the first drop of moisture you will get an audible and visual alarm indicating that you need to get out of the water asap. With proper maintenance and careful installation, you will probably never even need this feature, but in the rush of getting ready for a boat, it’s nice to have this safety net to rely on!

Three more useful items are included in the package – a comfy hand strap for easing the strain on your wrist, a lens cap to protect the port when not in use or when traveling and an LCD anti-glare hood to help you see the screen during strong daylight.

The housing with the camera inside is set to have slight positive buoyancy, so that if you happen to lose your grip without securing it to yourself (Which you should have done!), then you won’t lose it to the deep blue.

Overall, excellent housing and very affordable!

Update – The FRX100 IV is out! It’s almost identical to the FRX100 III so this review is very relevant.

Check out Fantasea’s Promo Video for the FRX100 IV:


Using the RX100 III Underwater

As I noted before, what I liked best is the ultra fast auto focus the RX100 III is capable of. My first photos with it were shooting a Blenny, and before he could even react to my presence, I have already snapped a perfect capture of him.

Blenny taken with a Sony RX100 III and +10 closeup lens.
Blenny taken with a Sony RX100 III and +10 closeup lens

Switching between modes was very easy and I mostly shot M- manual, since I prefer setting the shutter to a fixed 1/125 or 1/200, and playing around with the aperture and strobe power to control my lighting. The access to both dials is very intuitive so I could change my aperture with the ring dial on the side of the housing, while the rear dial is used to control the shutter speed.

All of the controls on the housing were very responsive and easy to operate on all depths I tested. The housing is rated down to 60m, but I only used it down to 28m on my test dives.


This is one of the areas where the RX100 III really shines. It is capable of full HD 1080p 60fps video, with excellent focusing and very good sharpness.

Check out these samples here:

Coming soon…

And a comparison with the Canon G7X here:



BigEye – As you probably know, using a flat port underwater changes the focal range by about 25%, increasing your zoom range but reducing your wide angle range. In order to recover those lost 25% on wide angle shots, you need to get a dome port in front of your flat port, which creates an optical effect which cancels that focal range change.

The BigEye does exactly that. It is a screw-on dome, which contains trapped air inside, having no optical effect above water, but underwater it creates a much wider angle of view, improving your photos immediately. The BigEye itself has a 67mm thread, but using the included step-up ring, it screws on the FRX100III 55mm port and can easily replaced or removed underwater.

RX100 III + BigEye lens, Dual strobes
RX100 III + BigEye lens, Dual strobes

RedEye / PinkEye – A simple red / magenta filter designed to bring back some of the colors which are lost as you go deeper. Using a 55mm thread they fit directly on the front port.

SharpEye – A closeup lens which comes in two different strengths – +4 or +8, designed to decrease the minimum focusing distance of the camera’s lens and create a magnifying effect for small critters.

RX100 III Macro shot of Blenny, taken with a Fantasea SharpEye +4 stacked with an Inon UCL-165.
RX100 III Macro shot of Blenny, taken with a Fantasea SharpEye +4 stacked with an Inon UCL-165.

EyeGrabber 55mm – A useful lens caddy to mount on your flex arm which can hold your BigEye or SharpEye when not in use.

Bottom Line

The Sony RX100 III is one of the best compacts in the market today. It’s ideal for underwater since it is small, packed with features and produces amazing quality thanks to its 1″ sensor.

Bundled with the Fantasea housing, I think it’s one of the best deals you can find at the moment. For those of you who prefer to travel light without compromising on quality, the RX100 III bundle is the perfect choice.

Images were all taken with a Sony RX100 III in the Fantasea housing, using one Inon Z240 strobe and one Sea & Sea YS-01 strobe. Macro shots taken with Fantasea SharpEye +4 stacked with Inon UCL-165 and wide angle shots taken with the Fantasea M67 BigEye.

The bundle is available here.

Check out more shots taken during my test dives here:



Ran Mor
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