The Sony Cyber-shot DSC-RX100 V, Submerged


Many serious underwater photographers travel with large DSLR cameras in huge housings. They also need a variety of lenses, ports, lights, and other accessories. As housings for small point-and-shoot cameras became accessible, underwater photography has become very popular.

Above photograph:  Amanda Cotton, using Fantasea Line FRX100 IVRon Watkins

In the past, these cameras had many limitations, such as small sensor size and slow autofocus. Most of these cameras only featured autoexposure, with no RAW file capture, which was not ideal for shooting underwater.

The RX100 V’s fast response allowed Ran Mor to capture this giant Hogfish at a cleaning station.Ran Mor

Today, there are several advanced point-and-shoot cameras with specs that benefit the serious underwater photographer. The Sony RX100 V is one of the best. This compact camera is only 4.0 x 2.3 x 1.6" and weighs 10.55 ounces. On the inside, this camera has a large 1" CMOS sensor that produces a 20.1MP image.

Sony Cyber-shot DSC-RX100 V Digital Camera

Because of the processor, image quality is exceptional and low-light performance is excellent, with low noise levels. The camera produces images that are very close and often comparable to ones produced by a camera with an APS-C sensor. In addition to quality stills, the camera captures 4K video and 4K slow motion.

The fast, hybrid autofocus system has 315 phase-detection points. The built-in Carl Zeiss Vario-Sonnar 8.8-25.7mm (35mm equivalent: 24-70mm) lens has a fast f/1.8 (W) - 2.8 (T) aperture. The camera also offers manual exposure control in video and still modes.

Queen angelfish at Garden of the Queen, Cuba Howard Rosenstein

Of course, this extraordinary camera would be of no use to the underwater imager if a quality housing did not exist. There are several companies that produce housings for the RX100 V, including Sony. It is important that a housing manufacturer understand the needs of underwater image makers. Fantasea Line’s founder, Howard Rosenstein, has been involved in underwater photography for a lifetime. As owner of one of the first diving and live-aboard SCUBA operations in the Red Sea, he was David Doubilet’s guide for his first National Geographic article. Rosenstein is also a member of the SCUBA Diving Hall of Fame, and an accomplished underwater image maker himself.

Caribbean reef shark at Garden of the Queen, Cuba Ran Mor

For the above reasons, it is no surprise that the Fantasea Line FRX100 IV Underwater Housing is a gem of a housing, with a reasonable price tag. This compact yet sturdy housing is rated to a depth of 200' (60m) and allows access to all essential camera controls. Since Sony did not change the size or control placement, this housing is compatible with the RX100 III, IV, and V cameras. To get the best underwater images, photographers should have access to “wet” wide-angle and macro lens accessories. It is also beneficial to use dual strobes, video lights, or a combination of the two. The Fantasea Line FRX100 IV lens port allows you to attach wide or macro wet lenses. The housing has dual fiber optic cable ports for using strobes. The bottom of the housing has three ¼"-20 sockets. It is best to employ a tray that uses two of these sockets, so it does not twist. The housing even has a moisture alarm with flashing red light. This is unheard of in housings in this price range.

Chase Darnell using Fantasea Line FRX100 IV Deyvi Urrutia Vanegas

Because of the quality and compact size of this system, many photographers are now using it in place of their large camera systems, or as a backup. This includes Emmy award-winning underwater videographer Becky Kagan Schott. Other noted photographers include Amos Nachoum, Amanda Cotton, Chase Darnell, Christian Petron, and Elisabeth Lauwreys. Captain Wayne Hasson, of the Aggressor fleet, offers this housing to all guests to try out for free.

Emmy award-winning UW videographer Becky Kagan Schott with stellar sea lions, British ColumbiaTrisha Stovel

This system has some practical advantages over a large camera rig. The first rule of underwater photography is, when you think you are too close to your subject, get closer—even very clear water has stuff in it. To be close and fit a large subject in the frame, ultra-wide-angle lenses are required. The RX100 V has a zoom lens that is 24mm at the widest point. For large subjects, we should add a wide-angle conversion lens. For small subjects, we need to increase magnification with a diopter or macro lens. When shooting with interchangeable-lens cameras, we must decide which lens to use before diving. Image makers do research on the dive site before deciding to use a wide-angle, fisheye, or macro lens. Even with the best research, you usually see a whale shark when the macro lens is attached, or a rare Nudibranch when using a fisheye lens! With a compact camera system, you use wide-angle and macro conversion wet lenses on the outside of the housing port. With this system, you could change lenses underwater. Now you can capture whale sharks and Nudibranchs on the same dive.

Ran Mor got close to this large black grouper with the UWL-09F wide-angle lens. The dome was almost touching his face, and he barely blinked.Ran Mor

A smaller camera means a smaller housing. The Fantasea Line FRX100 IV dimensions are only 6.1 x 5.7 x 4.7". Conversion wet lenses are smaller and lighter than DSLR lenses and the ports required to use them underwater. A compact housing will pack up smaller than a DSLR rig, and with airlines increasing luggage restrictions, this reduces cost and conserves space.

Spiny Head Blenny captured with Fantasea UCL-05LF macro lensHoward Rosenstein

The conversion lens used on the outside of the housing also needs to be a high-end optic. Fantasea Line and AOI have teamed up to produce a premium line of wet lenses. The UWL-09F wide-angle has five multi-layered precision-optic quality elements organized in five groups. This provides edge-to-edge sharpness. Since everything underwater appears 0.45x larger and closer to our eyes and camera lens, using a dome port corrects this size distortion. The UWL-09F has a built-in dome so the lens has a super-wide 130-degree angle of view. The lens allows the camera to focus extremely close and stays in focus even when the camera’s lens is in the wide-angle or telephoto position. A subject sitting on the dome will be sharp. Aside from capturing large subjects, this lens allows image makers to produce wide-angle close-ups and over/ under images. In the past, only interchangeable-lens rigs could capture these kinds of images.

Over/ under shots are not easy to achieve with a compact camera system. Ran Mor captured this sea grass in the mangroves scene using the UWL-09 wide-angle lens.Ran Mor

Fantasea and AOI also produce three macro lenses. The UCL-05LF and UCL-06LF have +6 and +12 diopter values, respectively. The UCL-09F is a super-macro lens, and has a +12.5 diopter value. All these lenses have optical glass elements and anti-reflective multilayer coatings, allowing you to capture sharp close-up images equal to shooting with a dedicated macro lens.

Howard Rosenstein used the Fantasea AOI UCL-05LF Macro lens to photograph this fairy basslet.Howard Rosenstein

All the Fantasea/ AOI lenses have 67mm threads; the FRX100 IV lens port has 55mm filter threads. These lenses can be used with a step-up ring, which is supplied with the housing. The UCL-05LF and UCL-09F macro lenses also have forward 67mm filter threads, so you can stack extra diopters for even greater magnification.

Close-up of Batwing Coral Crab during night dives in Gardens of the Queen, CubaRan Mor

In conclusion, the serious underwater imager can now create quality stills and videos without hauling around huge housing systems. The Sony RX100 V, with the Fantasea Line FRX100 IV housing, produces stunning results as is, but can increase image range and quality when paired with the correct wet lenses and lights.

Ran Mor was only inches away from this great barracuda, using the UWL-09 wide-angle lens.Ran Mor

This video offers a thorough overview of the Fantasea Line’s RX100 system.