By Jean Rydberg

Sony Alpha a7 series cameras have made a big impact on full frame underwater photography since their introduction in 2013. The new Sony a7R IV builds on this legacy with impressive performance in both still and video modes.

The a7R IV introduces a brand new 61 megapixel back-side illuminated CMOS sensor. Sony advertises a very wide dynamic range of up to 15 stops and 567 on-sensor phase detection points for very accurate autofocus performance. Unfortunately the maximum dynamic range is only realized when shooting downscaled 8MP images. Checking focus is easier with a higher-resolution 5.76M-dot electric viewfinder (EVF).

Underwater it’s ideal to be able to switch between high-resolution still and ultra HD video, and the a7R IV has the same great video performance as the esteemed a7R III. You can shoot either 24p or 30p from the full width of the sensor, meaning your wide angle lenses are just as wide in video mode as they are in still. This is crucial for great underwater footage where you need to be able to get as close to your subject as possible.

The camera’s CIPA battery life is quoted at 530 shots per charge when using the EVF and even higher 670 shots when using the camera’s rear LCD in live view mode. It's likely that you'll get even better battery performance than these estimates- especially if you use power saving functions wisely and shoot with TTL strobe exposure.

Compared to its predecessors, the a7R IV has a much deeper grip and redesigned control placement. The larger grip and differences in control positioning prevents it from fitting properly in housings designed for earlier a7 series cameras. 

A small camera mounting plate attaches to the bottom of the camera prior to installation in the housing. Memory card and battery are accessible with the mounting plate attached. A central 1/4-20 threaded hole allow the mounting plate to be attached directly to a tripod for surface photography in between dives.

200DL Underwater Housing for Sony Alpha a7R IV

This new housing designed specifically for the Sony Alpha a7R IV camera builds on all of the ergonomic and functional improvements we've introduced over the past several years. The signature Dry Lock (DL) port system uses an externally positioned o-ring to keep water away from your camera’s sensor when making quick lens changes. The o-ring is highly visible, easy to maintain, and stays in the right position. Compared to designs that install the o-ring on the port body, the o-ring is less likely to twist or extrude during set-up.

Lens Support

Sony has the widest selection of full frame lenses designed specifically for its mirrorless E/FE lens mount system. There are lots of super sharp lens options from Sony, Sigma, and Zeiss. Additionally, the Metabones Smart Adapter allows you to attach most of the best Canon mount lenses with relatively little loss of speed or autofocus performance. 

While mirrorless imaging systems allow the camera bodies to shrink, mirrorless lenses aren't necessarily any smaller than their DSLR counterparts. Often they are actually larger and heavier. But if you’re going to make a choice to add weight to your system somewhere, lenses and lighting are the two places to do it.

We continue to cut weight from the housing without sacrificing performance, functionality, or durability. Where possible we have made material substitutions to reduce the weight of the controls, strobe connectors, handle assembly, and port system. The result is a travel-friendly housing that is up to 30% lighter than a comparable aluminum body model. It is also much closer to neutral buoyancy and creates less drag in the water- reducing fatigue and making it easier to shoot super macro and over-under shots.

Moisture alarms and warning lights may be necessary for opaque black housings you can't see into. Our crystal clear back provides a view of the camera and in the unlikely event of water entry, you can see it before there's enough for a sensor to detect it.

Trim Weight

Depending on your choice of lens and port you may need to actually add weight to the system. Now you can do at your final destination instead of lugging the weight along with you. The unique Trim Rail System # 47140 is super lightweight and compact for travel. Once you get where you’re going, simply add a standard lead scuba weight. The rail may be adjusted front-to-back on the fly for perfect balance when shooting video and stills.

Housing design, machining, assembly, and testing all take place at our sole facility in Indianapolis, IN, USA. Each housing is tested at depth in a pressure chamber and individually test fitted with a working camera to adjust all controls and confirm function. Controls can be micro-adjusted by the user using the included hex key tools to accommodate minor variations in camera tolerances. Anytime you have questions about the housing or camera, or how to get the results you want, you have a full team of experienced underwater photographers on call to support you.

A vacuum system allows you to check for leaks prior to entering the water- ideally the night before or at least 30 minutes prior to your dives. Our vacuum valve is low-profile and unobtrusive.

Confidence

The unique floating rear o-ring seal is highly visible, easy to maintain, and requires no lubricant. The elimination of an o-ring channel eliminates twisting and reduces the build-up of dirt and debris that can cause leaks. Three double-passivated high-grade stainless steel lid snaps ensure the perfect distribution of pressure on the housing's rear o-ring.

A built-in vacuum valve allows you to draw a vacuum on the housing after assembling and prior to entering the water. A vacuum system helps you to check for potential leaks by simulating water pressure at one atmosphere. Our vacuum valve is designed to be low profile to stay out of the way of hands and cords. 

There’s simply no substitute for being able to see your camera, the o-ring seal, and anything else that may be going on inside of your housing.

Zoom/focus is right at your fingertips. Super fine tune adjustments are effortless thanks to the 5-lobed soft-touch knob and internal gearing system. Zoom gears are lightweight, affordable, and available for most popular zoom lenses.

Controls and Ergonomics

Sony ergonomics may not be the best or most intuitive on the market, but the housing places everything you need underwater at your fingertips. A large 5-lobed soft-touch zoom/focus knob only requires the gentle touch of your left index finger. Shutter and AF-ON levers hug the housing when shooting with the standard handle configuration, and may be extended for perfect placement when using a right-hand handle.

All rotating and lever type controls feature soft-touch knobs. Push button controls are smooth and spaced far enough apart for comfortable use with or without gloves. Each control on the back of the housing is marked with laser engraving that can’t fall off or fade with heavy use. 

Back Button Focus

Back button focus is when you use the AF-ON button to lock focus instead of half-pressing the shutter button. It is simple and effective. Once you get used to the different shooting style, it’s invaluable for obtaining tack-sharp focus underwater, especially for super macro or fast moving subjects.

Read more: Getting it Sharp: Back Button Focus and Post Processing Workflow

Custom Functions

Controls are included for the camera's custom function buttons. These buttons are even more useful with the release of the a7R IV, as they can now be programmed independently for still and video modes. 

Power Save

Conserving battery life is important with mirrorless cameras, but it's simply not reasonable to turn your camera off and on all of the time underwater. We can't tell you how many unexpected photo opportunities (you know- the best photo opportunities) have been missed because a camera was turned off to save battery for later. Instead, set a short power save interval so that the camera falls asleep automatically when not in use. The camera will use virtually no battery in this "sleep" mode and you just need to half-press the shutter or press any button to wake it up.

Go into the camera's menu settings and set Pwr Save Start Time to the shortest interval that makes sense- between 10 seconds and 2 minutes. Remote Control and Cntrl w/Smartphone settings must be turned off for this to work. You also have to make sure that you're not in one of the camera's menus, or it will prevent the camera from going to sleep.

Shutter release and AF-ON are brought out to the optional right-hand quick release handle using the Trigger Extension # 4077.93. This is the magic combination of controls to use back button focus.

Electronic Viewfinder (EVF)

The standard Supereye viewfinder provides an enhanced view of the camera’s EVF when shooting underwater wearing a dive mask. If you’ll be shooting a lot or have bad eyes, treat yourself to an enhanced magnifying viewfinder. Enhanced viewfinders are available in 45º angled and 180º straight models. These viewfinders can be installed quickly and provide a significantly brighter, wider, and more clear view of the camera’s EVF. Both viewfinders rotate for landscape or portrait shooting. High quality viewfinders are a great investment that can stay with you down the road when you upgrade to a new camera.

Read more:  Straight vs 45 Degree Magnified Viewfinder for Underwater Shooting

Once you try shooting with a 45º Magnifying Viewfinder you'll wonder how you ever composed an image without one. The viewfinder rotates for shooting portrait or landscape orientation.

Strobe Shooting

Color fades fast when you go underwater and the only true remedy for that is to bring powerful lighting with you. The housing comes standard with an ICS-5 electrical bulkhead and manual flash hotshoe. The ICS-5 bulkhead is favored over the old Nikonos V variety for its reliability and ease of use.  Lightweight electrical sync cords are available for Ikelite strobes, as well as SEA&SEA, INON, Retra, and other brands.

TTL strobe exposure is possible by adding the DL2 DS Link Sony TTL Converter Ikelite ST1 Hotshoe Kit # 46042 and a compatible Ikelite DS strobe. Electrical TTL triggering is faster, more accurate, and more reliable than fiber optic TTL. Electrical TTL also conserves battery life (camera and strobe) for significantly more shots over a series of dives. TTL strobe exposure is useful in both macro and wide angle applications and allows you to have more time to focus on composition and camera settings.

Don’t confuse TTL “auto” strobe exposure with the “auto” camera mode- TTL strobe exposure is supported by the camera even when shooting in Manual camera mode, allowing full control over ISO, aperture, shutter speed, and other important camera settings. TTL flash is the standard for surface photography and it happens to work even better underwater when you're using one of our TTL systems.

Read more: The Myth of TTL Strobe Exposure Underwater

A 1/4-20 threaded top mount is the perfect place to mount a focus light or GoPro camera. 

M16 Accessory Port

A spare M16 threaded accessory port is built into the top of the housing for the attachment of third party accessories, most notably for HDMI monitors. We recommend contacting Dive and See who offer a variety of monitor solutions and have experience fitting monitors to Ikelite housings. Nauticam also make some bulkhead accessories which may be fitted to this port.

Conclusion

The a7R IV is a solid performer and among the top choices for underwater among mirrorless cameras. While it doesn’t provide a compelling reason to upgrade from the a7R III, Sony does keep pushing the bar higher for mirrorless technology and this is an awesome choice if you are ready to make the switch to mirrorless from a compact or a DSLR.

Read more:  200DL Underwater Housing for Sony Alpha a7R III # 71474

Jean Rydberg is the President & CEO of Ikelite. She has lived her whole life in landlocked Indianapolis, Indiana, but is no stranger to the water as a daughter of Ikelite’s founder Ike Brigham. She has traveled around the world shooting and testing gear and enjoys new challenges in both photography and diving. Jean loves to learn about the creative ways photographers achieve their visions. More than anything she wants to show aspiring underwater photographers that excellence is attainable with any system. When she's not working she's spending time with her husband and two daughters.