Canon Underwater Housings - Helpful Information

I own a G10 (WP-DC28) and G12 (WP-DC34) housing. My experiences with these housings may also apply to other Canon models as well as other brand polycarbonate housings.

CRACKED LOCKING BUCKLE

I discovered a crack on the WP-DC28 locking buckle (shown below) after approximately two years of use. I applied some Super Glue to it and time will tell if it works. Others have suggested using a section of thin stainless steel wire, heating it, melting it into the buckle then applying a glue over the wire and sanding it smooth. Hindsight being 20-20 I believe you can significantly reduce the risk, if not prevent cracking the buckle by COMPLETELY closing the housing back door by hand. The most amount of strain is put on the buckle when the O-ring seats in its groove.
DAMAGING THE TRIPOD MOUNT
The tripod fitting is a metal plate attached by four screws to a polycarbonate mold as shown below. Applying too much stress to this fitting can cause the threads to strip or break. All four of the thread shafts are broken off in the below photo. In hindsight attaching straps connected by a cable tie to additionally secure the housing to the tray as a means of relieving the stress on the tripod mount is explained further down in this section.
Many underwater camera trays accommodate a variety of housing brands and sizes. The housing is attached to the tray via the housing's tripod mount (arrow #1 below). Note the WP-DC34 housing feet do not touch the tray (arrow #2) even with the tripod mount flush with the tray. The two "feet" on the bottom rear of the housing are against the rear raised lip of the tray (arrow #3) to prevent the housing from turning. Also note the back door of the housing does not rest on or against the tray (arrow #4). If the feet rested on the bottom of the tray tray or the door rested against the tray lip it may put pressure on the door causing it to shift resulting in a leak or a total flood.
The downside of the above mounting scenario is all the pressure is put on the tripod mount when holding the camera housing in your right hand instead of the tray handle with a housing/tray/arm/strobe combination like the one below that is not neutrally buoyant. Under some buoyancy situations it is not always possible to hold the tray by the left side handle and push the shutter button with the right hand. These type tripod mounts are not intended to bear that kind of stress.
My solution to alleviate the stress on the tripod mount is to additionally fasten the housing to the tray with two nylon hand straps from two pet leashes (with the chains removed) and one cable tie. As shown in the photos below the straps are inserted through the top neck strap loops on each side of the housing. The leashes are then pulled down across the front of the housing and joined together with a cable tie underneath the tray. I cut the cable tie off and discard it at the end of a dive day. I purchased a bag of cable ties. It is not possible to open the housing door while mounted to this tray.
The MOST IMPORTANT part of this method, or any other, is to be certain the pressure is equally placed on the tripod plate. To check this (after securing the straps to the tray) loosen the tripod screw and check that the housing does not lean forward or backwards as that will put pressure on either the two front or the two rear tripod plate mounting screws.

 
No doubt there are more creative methods of reinforcing the tripod mount. I would be cautious of placing any objects under the housing. They may create upward pressure causing a portion of the housing to flex which in turn may cause a leak or flood. This is even more of a concern if those objects were under the door portion.
FACTORY MOLD RELEASE LINES
Some housing owners suspect the so called "mold release lines" (slightly raised areas) in the O-ring groove on the door of the housing may cause the housing to leak. Some have suggested sanding down these "mold lines" with 600 or 800 sandpaper to allow the O-ring to better seat in its groove thereby preventing any possible leakage. I am not advocating that process here but simply pointing out the locations of the "mold release lines". The lines on my G10 housing are less pronounced than those on my G12 housing. The lines on my G12 housing are indicated in the below photos.
DRAWBACKS TO USING ONLY THE INTERNAL FLASH
The length of the lens tunnel on the WP-DC28 AND WP-DC34 housings results in a dark area on the lower right portion of close-up macro photos when using only the camera's internal flash. The flash is partially obstructed by the housing lens tunnel due to is length. The included flash diffuser does not solve the problem. One solution is to back away from your subject then crop the photo in post-processing. Another solution is to place your subject in the upper portion of the monitor then crop the photo in post-processing. The best solution is to use a slave strobe. This problem is not as distinct in camera models with less zoom as the lens tunnel would be shorter. If you are buying an underwater camera and don't plan on using a slave strobe be sure to choose one that has the least amount of impairment using the internal flash.

In the below photo note the difference in lens tunnel lengths between the Canon S90 and the Canon G10 in their respective Canon housings. The S90 and S95 have pop-up flashes which may place the internal flash slightly higher than the fixed position flash on the G10, G11 and G12.

Below photo was taken with a G10 in a Canon WP-DC28 housing 4" from the subject in the Macro setting using the supplied housing diffuser. Note the darker areas in the lower portions of the photo.
STICKING CONTROL BUTTONS
If some of your housing control buttons are sticking or are hard to push apply a drop of pure silicone to the exterior of the respective buttons using a toothpick. Place the silicone in the open portion of the button shaft. Work the silicone in by pushing the button several times until it feels loose. It is best the housing is dry before applying the silicone. The below photo is of food grade liquid silicone that can be purchased at some dive shops.
MORE TOPICS

Dangers of using the GPS feature on your camera

Removing Backscatter & Particulate Matter in Photoshop (CS4)

Processing "White Balance" on RAW photos (CR2 files) in the Canon DPP software program
   

Homemade Combination Fiber Optic Slave Strobe Cable Attachment & Camera Strobe Deflector
   

Substitute methods for no rear control dial on the Canon WP-DC28 housing using the G10 camera
   

Substitute methods for no front or rear control dial on the Canon WP-DC34 housing using the G12 Camera

Preventing Housing Lens Fogging
I hope you found some of this information helpful.
Jim Spears
islandjim@gmail.com