Just spent an hour on the mountain behind my house with the camera still stupidly set to maximum positivecompensation (left over from some night shots at ANZAC Dawn Service), and followed that first newbie mistake with a second one (that would have solved the first one) by not checking any of the preview images as I was shooting. I'd have seen immediately that they were over exposing on the very first shot had I been checking the previews.
Everytime I think I'm getting somewhere I do something so totally stupid. EIGHTY FOUR SHOTS all blown to hell. It sounds like a lot for an hour on a hill, but I was getting the dog to run towards me, and using high speed drive, so was cranking out about 10-15 shots at a time.
So. To other people new to photography, please from my pain. Know what your camera is set to, and check images on the preview screen after taking them to see if you need to change anything.
Now to go smack myself upside the head and berate myself for a few more hours.