Now that I have something to transfer my pics to the computer, I've started using my camera outside. The problem is, it won't work. Each time I've tried it's been over +20 degrees Fahrenheit outside. I have a a digital SLR- a Canon EOS 10D.

I went out, took pictures, and after less than an hour it started acting funny. At first it wouldn't take pictures when I pointed it upward and gave an "error 99". I had to turn it off and on again to clear the error. When I checked the pic, it was completely black. I tried putting in a fresh battery I had with me, but that didn't help. After a little while it wouldn't take them no matter which way I pointed it. At one point I was able to watch the shutter close, so I think that had something to do with the errors I kept getting.

When I came back in I discovered that some of the pictures I had taken before I started getting the errors were completely black, some taken as few as 15 minutes after going outside.

After the camera had been inside for awhile and warmed up I tried using it, and it worked fine. In fact it's been working fine indoors ever since. But if I go out for any length of time... some of the pics will be black.

Is that normal for digital cameras? For my model? What could be wrong?