I usually just hide the camera under my jacket until I want to take a picture and pull it out and not worry too much about a drop or two or 20, but I wouldn't have it out in the rain if it was raining hard or for a long time in light rain.

I had my 5D mark II out in heavy snow in the winter and the next day it wouldn't turn on.  I don't know if it was the snow that did it or not (I kept it protected pretty well).  I got it fixed on warranty but it was still a pain.

used a ziploc bag in Antarctica with my 5D2, worked a treat

Your right leaf, a plain plastic bag and some tape has only a few less features than the $200 model on B&H.

Maybe you can modify one of these to suit your needs  




Just kidding... I have used a plastic shower cap but usually use leafs method of hiding the camera under my coat.

edit: claude you beat me to it

Yeah, i just went and looked at BH photo and they have quite a few options but I can't believe they are $50, or $100.

Here is the DIY fancy version.

Buy an el cheepo rain jacket from the hardware store $5.00 or so.. this version is much more durable than the plastic bag.

Stick the lens through the neck of the jacket and do up the snaps so just the lens hood sticks out.  You can reach your arms backwards through the jacket arms to reach into the coat and control your camera.  Put your head in the main body area of the jacket to look through your camera.

I use a Storm Jacket (www.stormjacket.com) with my 1D Mark III.  My camera is weather sealed and I still get nervous in heavy rain.  I think you are nuts to go out with a 5D in serious weather unless you have an assistant holding a very large umbrella over you and there is no wind. 

Just my .02,

Mat