This is a "raincoat" I made for my camera from an old air mattress. I shoot a lot of soccer matches and sometimes they play in the rain, so a device like this can be very handy. I also carry a 3-mil 45 gal plastic bag in my camera bag where I can put my entire camera bag in case of a real downpour. Previously, I had used a golfers umbrella held to my monopod by a homemade snap-on bracket, which was fine for a light shower, but if there was a significant wind it became unreliable and difficult to manage, not to mention moving the camera around. I know there are commercial versions of this type of device available, but I did not look at those when designing mine. I simply used an old air mattress (it had a slow leak & was going to be thrown out) and cut and trimmed until I found what appeared to be a useable design. At this point it has not been field tested, so cavet emptor! I expect it should work just fine, although the current design probably won't provide adequate protection for rotating the camera into the vertical orientation (not something I do often when shooting soccer). I may add a modification to alleviate this problem though.
UPDATE: Problem solved! I have added a flap to the right side to provide protection when shooting with the camera in the vertical orientation. Thanks to Dave Harvey for bringing this to my attention.
