This has happened several times on glaciers where it's been too bright for me to notice so I've ended up losing pictures. Somehow when I put my camera (Rebel XTI) back in a case and take it out again, the ISO jumps from whatever I had it at (usually 100) to 1600 and ruins pictures taken until I notice and change it back.
In this scenario I'm typically shooting in "AV" (shutter priority mode?). I haven't been able to repo the problem intentionally to find out what combinations of buttons are being pressed in order to be more careful.
Does anyone know what might switch the ISO from 100 to 1600 for holding down a button if the mode isn't changed?
Thanks for the tips / discussion. I do shut the camera off prior to putting it back in the case, so I'm not sure what could cause the setting change. It's possible but unlikely I'm bumping something as I do that. The keep-alive battery seems ok as pictures are labeled with the proper date-time. In the most recent case at least, I didn't accidentally change the mode as I was still in AV mode and suddenly had 1600 ISO the next time I took it out.