Jeroni Paul said:
Given all your described sympthoms I would say it is the CCD sensor
starting to fail. It is showing some dark rows across the pictures,
typical of problems with these sensors. These dark rows make the
camera think the picture is darker than it is and increases exposure
to compensate. When you see the picture on its LCD live it is not
analyzing all the rows but a small fraction and these failing rows
have no impact at all, so it appears to work properly. But when you
take the photo it processes all the information.
That sounds quite possible - especially as the sensor had been exposed
to very cold conditions for the first time and I now discover that
sensor faults were not unknown in early versions of this model.
I think the sensor will have to be replaced (if worth) but meanwhile
you can lower the exposure manually as you did as a workaround.
I've sent it away for repair and the quote was for a 'replacement lens
unit' (which presumably includes the sensor).
Consider also that overexposed photos may be corrected to some degree
with an editing program that can correct brightness/contrast. I get
quite good results with MS Office photo editor, my camera has a
tendency to take pictures too dark mainly under artificial light and I
fix some of them before printing.
Most pictures were so severely 'crushed' that no recovery was possible -
I did manage to use one but it was a struggle.
