During previous trips to the Caribbean island of Cayman Brac, in the Cayman Islands I used a Sony RX100 in a dedicated underwater housing with very good success. On my most recent trip I decided that it was time to take my Nikon D800 & Nikon D500 into the ocean, however, I could not really justify the expense of a dedicated housing for these cameras at this point in time. Since I would only be using the cameras while snorkeling, I was planning to rely solely on ambient light for underwater photography. After a bit of research I decided that an Ewa Marine underwater housing would be my choice of housing for the recently concluded trip to Cayman Brac. I purchased the Ewa Marine U-B100 housing which is designed for use with professional cameras and for lenses with a filter diameter of 77mm or 82mm. The housing comes with the 77mm adapter (the 82mm adpater is optional) that allows you to firmly position the lens inside the lens port and flush against the optical glass element. The Ewa Marine housing is made from special, multi-layered, laminated PVC to ensure safety and durability and all seams are double welded. Two rails are fastened together by means of three thumb screws to securely close the opening to the housing. There is a sepcailly designed pocket molded into the design for your finger to reach the shutter release button on the camera. All other functions are accessed through the thick laminated PVC – a difficult but not impossible task.

Spotted Stonefish, Cayman Brac, Cayman Islands
Nikon D500
Nikkor 18-35mm @ 32mm (48mm effective focal length)
ISO 500
f16 @ 1/125 sec
On my first snorkel trip with the Ewa Marine housing I quickly discovered that I had left too much air in the housing and was subsequently very hard to dive down with the housing. I opened the housing and using a straw sucked out as much air as I could and then re-sealed the housing, which worked perfectly.Ewa Marine does sell an optional lead weight that goes inside this housing and after using the housing for a couple of weeks I believe that the weight would be an added benefit to using this housing.
As I researched this particular housing via blogs and You Tube videos there was a common theme. One was that the lens adapter was very difficult to fit against the optical glass port and the other being virtually impossible to operate camera controls and zoom lenses. I had no difficulty whatsoever fitting the lens into the lens port and while camera functions are more difficult to adjust I was able to make exposure adjustments and zoom the lens as required while underwater.

Peacock Flounder, Cayman Brac, Cayman Islands
Nikon D500
Nikkor 18-35mm @ 32mm (48mm effective focal length)
ISO 500
f16 @ 1/200 sec
I used both my Nikon D800 and Nikon D500 cameras with no issues at all. My lens of choice for use in the housing was the Nikkor AF-S 18-35mm lens which did vignette slightly, at 18mm, on the Nikon D800. When the lens was zoomed to about 20mm the vignetting disappeared. I chose to use the 18-35mm lens as it focuses down to 12 inches throughout it’s focal range. In underwater photography the closer you can get to your subjects the better the image quality will be. You must minimize the amount of water between you and your subject for better clarity.
I am looking forward to using the housing on Horseshoe Lake this summer where I will use it for frog photography and freshwater fish imagery too. If you are curious about trying your hand at underwater photography I would highly recommend an Ewa Marine housing to get you started. I purchased my Ewa Marine U-B100 housing from B&H Photo. Please note that I am in no way affiliated with Ewa Marine or B&H Photo. I simply wanted to provide you with an honest, real-world review after my experience with this housing.
I am often amazed by the ability of ocean fish to superbly camouflage themselves. This is especially evident in the highly venomous Spotted Stonefish, a member of the scorpionfish family. Fortunately Stonefish only use their venom as a means of self-defence, however, accidentally stepping on one does mean a trip to the nearest hospital!
Please do remember to click on each photo to see the larger, sharper version. Which one is your favorite?

Southern Stingray, Cayman Brac, Cayman Islands
Nikon D500
Nikkor 18-35mm @ 34mm (51mm effective focal length)
ISO 500
f16 @ 1/320 sec

Spotted Stonefish, Cayman Brac, Cayman Islands
Nikon D500
Nikkor 18-35mm @ 24mm ( 36mm effective focal length)
ISO 500
f16 @ 1/160 sec