Ewa-Marine U-B 100 Underwater Housing for DSLR Cameras Review

Ewa-Marine U-B 100 Underwater Housing
In-Depth Review

Around the world, a huge number of activities are focused on/in/near/under water and water has proven unfriendly to electronic gear including cameras. However, water activities provide great photographic opportunities. The affordable and effective Ewa-Marine U-B 100 Underwater Housing is the passport for your camera to join these wet events and adventures.


The U-B 100 Underwater Housing and I became acquainted during my St. John, US Virgin Islands trip planning. I had been to this beautiful island before and knew that the snorkeling experience there is amazing. I had decided that I was going to have a DSLR camera with me during the underwater experience on this subsequent trip.

For those spending significant amounts of time and effort shooting underwater, a dedicated rigid underwater housing is the best option. The rigid housings provide excellent grip and full control over camera and lens settings. I'm not one to compromise on the gear I'm using, and my underwater photography plan included acquiring one of these hard underwater housings for my EOS 5D Mark III. If you have shopped for and used conventional DSLR camera rigid underwater housings, you are aware of some of the following points.

Quality rigid underwater housings are very pricey. It is not hard to spend more than a very nice DSLR for just the housing and adding a pair of strobe lights on brackets can easily double the price.

DSLR shape and switch layout necessitate that housings are generally dedicated to a single camera model. In addition, the interchangeable lens ports will fit only select lenses.

DSLR housings are quite bulky, making them not-so-comfortable to travel with. They do not collapse in your bag and you probably do not want to stuff them full of your socks. They are also somewhat heavy.

Quality underwater housings seldom leak, but because of the unequal pressure between the air inside of a rigid housing and the water outside of it, especially when diving deep, any imperfection in the seal can result in a wet camera.

I don't shoot underwater regularly and for that reason alone found it hard to justify the price of a rigid housing. By the time I go on my next similar trip, I will not likely be using the same camera model.

The high underwater housing price is also hard to justify if you are not scuba diving. I do not scuba dive (for time and cost reasons alone as I'm sure that I would love it). When diving from the surface to approach fish and other living creatures at their level, they swim away due to the pressure wave. It is also very difficult to stay down deep without a weight belt, but a weight belt is a bit of a safety hazard when snorkeling. Thus, it is not likely that a snorkeler is going to get the same photo opportunities as a scuba diver, meaning the return on the underwater housing investment is not as high for this pursuit.

I seriously considered renting underwater gear and still think that is a great option for infrequent snorkelers and divers.

Another alternative is to use a point and shoot camera with a dedicated underwater housing (I've used a Canon Powershot G9 in a dedicated underwater housing). While these P&S setups work well and are quite affordable, I'm not satisfied with point and shoot image quality, especially in darker underwater environments.

Another option I considered was buying an older DSLR camera model along with a used underwater housing. Housings for new camera models are in hot demand, but housings for older cameras have a far lower demand. Buying used generally involves some level of risk, but a housing is not too difficult to test for sea-worthiness and functionality.

After a long consult with an underwater photography expert, I took another option. I selected and purchased the far-more-affordable Ewa-Marine U-B 100 Underwater Housing. This housing much more closely resembles a re-sealable plastic bag than a conventional rigid underwater housing, but it fortunately is far stronger and more durable than what you find in your kitchen drawer. Ewa-Marine has a wide range of underwater housing models designed to fit a wide range of camera models with size being the biggest factor in model selection.

The U-B 100 model is designed for up-to mid and larger-sized DSLRs including the Canon EOS 5D Mark III and the Canon EOS-1D X with 77mm or 82mm thread-diameter lenses mounted (or smaller lenses with step-up rings in use). The U-B 100 will work well for a wide range of other current and previous models from a range of manufacturers (including Nikon) and, a key to the great value of this housing, should support a huge range of future models.


Overall, the Ewa-Marine housing is flat with primarily the lens port and also the bottom protruding. The primary material used for this housing is clear "double laminated PVC" [Ewa-Marine]. The PVC is thick, but remains pliable. The bottom of the case includes an extra layer of protection (in high-visibility yellow).

Ewa-Marine U-B 100 Right Side

An adjustable/removable hand strap is provided on the right side of the case where you would expect it to be. Attachment points for the hand strap are very solidly welded to the housing.

The lens port is securely welded to the primary housing and is designed to extend or retract as needed. The lens port is optical glass surrounded by plastic and sealed to the rest of the housing with a metal band.

A seemingly-thicker viewfinder port is provided and a finger insert is provided for the shutter release.

Ewa-Marine U-B 100 Back

The top of the housing closes flat. Like a plastic bag.

Ewa-Marine U-B 100 Back Open

Three small holes in the PVC accommodate the brass threads on one of the two beveled-aluminum rails. The other rail has three thumb screws held captive to both rails via a PVC strip. The two rails pinch the PVC between them and tighten via the thumbscrews.

A removable/adjustable hand/neck strap is attached to one of the rails. All hardware is salt-water-corrosion-resistant. The U-B 100 in the above pictures spent 25-30 hours in salt water prior to being photographed.


To install the Ewa-Marine U-B 100 Underwater Housing, an adapter is first threaded onto the lens. The C-A 77 (77mm) adapter is supplied with the housing and the C-A 82 (82mm) adapter shown below is optionally available.

Ewa-Marine C-A 82 (82mm) Adapter Ring

Lenses with smaller filter thread sizes can still be used in this housing, but a step-up ring (to 77mm) is required. The adapters are aluminum with a rubber O-ring that fits into a grove inside the lens port. The O-ring in the grove anchors/positions the camera inside the housing. The maximum comfortable lens length to use in the 3.75" (95mm) long lens port is about 4.5" (115), with the two I've used, the Canon EF 16-35mm f/2.8 L II and EF 16-35mm f/4 L IS USM Lenses, being about as big as will comfortably fit.

While it is advertised that lenses as wide as 16mm can be used in this housing, the Canon EF 16-35mm f/2.8 L II and EF 16-35mm f/4 L IS USM Lenses both show physical vignetting at focal lengths wider than about 21mm when used on a full frame body. Both of the just-named lenses are great choices for use in this housing for many reasons in addition to their size. The housing does not interfere with autofocus. Note that fisheye lenses and other lenses without filter threads do not work in the Ewa-Marine underwater housing.

With the lens mounted to the camera and the adapter mounted to the lens, the setup is inserted into the port and firmly pressed into place. Not getting the lens inserted fully into the port increases the potential of vignetting. Don't ask me how I learned that. Getting the camera (preferably without the neck strap) into the case and properly aligned prior to firming the adapter into place is a little fiddly. The right rotation of the lens inside the port is needed for the housing's shutter release finger insert properly align with the camera's shutter release. This task is easier with a pro-sized body (with L-plate removed) as there is less room for adjustment and things fall into place easier.

I know that you've been thinking "What if I drop my camera in 100' (35m) of water?" Well, this housing is only rated for 60' (20m), so allowing it into extreme depths is not a good idea, but there is no worry anyway because the camera will float in this housing. How well it floats depends on the depth it is being used at and how much air you leave in the housing when closing it. The first consideration when making the amount of air decision is the depth you will be using it at. For shallow water use such as snorkeling, you will want as much air out as possible to permit easier diving. You may even want to use the optional 3.74 lb (1.7kg) Ewa-Marine BF1 Lead Weight shown below.

Ewa-Marine BF1 Lead Weight

If you are going deep, you will experience greater pressure and the air inside the housing will compress. In this case, you may need to inflate the housing before sealing it (and floating becomes questionable). A foam pad the same shape as the weight pictured above is included with the housing to act as an air reservoir. The foam also fills in the grip area when using a non-gripped body, creating a better fit into the housing.

Unlike a rigid housing, because the air pressure is equalized inside vs. outside, the risk of implosion is greatly reduced. In fact, Ewa-Marine claims that "implosions are impossible". More important to me is that the equalized air pressure greatly reduces the risk of water leaks.

Ewa-Marine supplies CD5 Desiccant Silca for reducing fogging inside the housing, but I did not encounter this issue even without the CD5.

After getting the camera into place and adding/removing air, sealing the housing is the next task. While not difficult, the process is slightly fiddly. Laying the two sides of the case together without wrinkles (or obstructions) that could break the seal is the minor challenge.

Ewa-Marine U-B 100 Open

The threads on the one rail go through the holes in the housing and the holes in the other rail. The thumbscrews then tighten down to seal the case.

Ewa-Marine U-B 100 Partially Open

At this point, the camera is underwater-ready. Keep a careful eye on the setup when submerging it. There will be some air bubbles, but these should all come from external sources (such as the rails).

When finished using the housing, rinse it off with clean fresh water. Then dry the bag and insure that there are no water spots left on the lens port. At this point, the installation instructions reversed become the removal instructions.

The two sides of the PVC bag naturally stick together. This makes the seal better, but also makes them harder to separate. A small notch at the top of one side of the bag facilitates the separation.

In Use

I spent about 25-30 hours underwater with the U-B 100 in St John, USVI. This was plenty of time to get to know the housing very well. Here are some of my thoughts on this housing and its design.

First and foremost, the U-B 100 worked as designed and did a fine job for me.


As one would expect, gripping a camera inside a thick plastic bag is not as easy as holding it without the bag. I found the hand strap to be very helpful for underwater grip, but this is not the most comfortable hand strap I've used. The plastic also inhibits use of the controls. If standing with the camera above water I could make some settings changes and could tweak focal length, but these tasks were challenging. If underwater, controls, especially dials and wheels, become very difficult or impossible to adjust. Best is to setup the camera for the task in front of it before sealing the case.

Reviewing images and checking settings is a challenge underwater and also above water under direct sunlight. I was practically unable to see the LCD on my 5D III or 1D X at most times during use.

The viewfinder, as one would expect, is more difficult to use inside of the case. If you are shooting underwater, you will need to wear swim goggles or a diving mask that adds a big layer of complexity to viewfinder eye alignment (I have trouble keeping a diving mask clear/unfogged without a viewfinder to look through). I frequently used the point and shoot technique as I could not get the camera and me both in place fast enough for viewfinder use underwater.

Most frequently, my shutter release aligns under the thick seam of the finger insert. The seam makes it very hard to find the shutter release and caused me to miss shots at times.

The larger hand/neck strap is very useful for carrying the camera when not in use, but I found it in the way during use. I don't know what the alternative is, but I have strap in a few of my images. Tucking the strap under my right hand before putting that hand in the smaller hand strap proved mostly effective during use. When used as a neck strap underwater, the tendancy was to slip off.

Though I've taken great care of it, the lens port exterior seems to get smudged easily and it is difficult to clean.


The quality of the images I am getting from the Ewa-Marine underwater housing is excellent. Because the housing uses a flat glass port (vs. a dome port), you are going to see increased (sometimes significantly increased) CA in the corners of the frame of your underwater photos. I specify underwater because you will not see this CA (and any other degradation is hard to detect) when shooting above water.

It is an "underwater" housing, but it is also very useful above water

The underwater use for this housing is obvious, but not so obvious are the many above-water uses for this housing. Do you like taking pictures of your kids, friends, pets, etc. in or around the water? Enjoy watersports? No longer do you need to stay far away - you can photograph the water play without fear for your gear. Have you been enjoying the shorebreak wave pictures that are popular and also very beautiful? This housing may be your ticket to enter that venue.

Wet Dog Shaking

Affecting your above-water pictures will likely be water drops on the lens port. It would be nice if the port glass had a hydrophobic coating to cause water drops to readily shed off, but dealing with water droplets is an issue. The tried and proven technique for water drop avoidance is to spit on the port (sorry - it is effective), smear it, quickly rinse underwater and shoot above water without much hesitation. The water film on the port will be even and generally not noticeable in the images.

Girl Diving

While the Ewa-Marine housing does not provide much impact protection (considerably less than a rigid housing), it does provide some scratch protection. There are some situations where this case could provide the non-liquid camera protection needed. Though I haven't had the opportunity to test this use, the U-B 100 appears to be the ideal camera protection for a color run where the colored powder being thrown infiltrates cameras and lenses (and, I'm sure, your lungs) and voids rental damage insurance coverage. Sand storms, mud splatter, salt water spray ... cleanup is just a gentle faucet away.

Dog Catching Ball

Some Ewa-Marine underwater housing models include a tripod insert. The U-B 100 model I purchased does not have this feature, but ... I'm thinking that tripod use could be a great capability extension of the housing – especially if your remote release fits into the case (or is wireless). For example, when a thunderstorm is approaching, the camera could be setup to continuously capture images (with lightning as the primary target) while the photographer remains safely indoors. Or, a timelapse could be captured unattended over a long period of time with rain or snow not being a concern for the gear longevity (though water drops on the lens port may compromise image quality). Underwater tripod use is a bit more complicated, but it is definitely an option.

Another Ewa-Marine model option is designed to accommodate a full size hot shoe flash. I did not opt for the flash model because backscatter (on-camera flash lighting up particulate in the water) is a problem and because I was not diving deep, I did not anticipate the need for auxiliary light. There were times when the flash could have been helpful, but ... I don't regret opting for the non-flash model. The increased bulk of the housing is probably the biggest downside of the flash model.

Technical Information

Dimensions (WxHxD): 8.7 x 6.3 x 3.9-7.9" (220 x 160 x 100-200mm)
Lens Port Diameter (and length): 3.75" (95mm)
Your Lens Filter Thread: 77mm (optional: 82mm)
Weight: 1.04 lbs (470g)
Material: Double Laminated PVC

Empty, this housing takes up relatively little space and weighs very little, making it great for travel and easy to store.

Included in the box is a high-visibility yellow nylon carry bag with a waterproof interior coating. While the large/narrow size of the case is not what I would have designed, it worked fine and I made good use of it. Sand does not readily stick to the case and with the camera inside, I was able to keep sand off of the housing. In storage, the case keeps dust off of the housing. The color is such that locating the case is not a challenge. I hung it from a tree while snorkeling to help locate my starting point when I returned.

Ewa-Marine U-B 100 Front


Underwater photography is extremely challenging, but it is also very fun and rewarding. I share some tips in this article: Underwater Photography Tips for Snorkeling.

The first step to shooting underwater is acquiring protection for the camera and lens. That is where the Ewa-Marine U-B 100 Underwater Housing enters the picture. The U-B 100 is not without downsides and it is not the right choice for everyone, but it is the easily-justified option for many uses and it has many significant advantages of its own. It is possibly the right choice for more people than all of the other underwater housing designs combined, and the U-B 100 was the right choice for me. I got a lot of attention when carrying the camera-loaded U-B 100 down the beach – everyone thought the design was a great one.

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Ewa-Marine U-B 100 Underwater Housing
Ewa-Marine U-B 100 Underwater Housing
The-Digital-Picture.com gives the Ewa-Marine U-B 100 Underwater Housing an overall 4.5 rating
Manufacturer ID: EM U-B100
Review Date: 2014-08-17
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