So , took out my Trusty D300s out after not being used for about 4 months ... Fully charged battery and spare .
Went to photograph a protest march in London a cple days ago ... weather was cold but not freezing .
On taking the first few shots, noticed that every second one was over exposed and the first one under exposed ..
took many more with same result ... this was in P mode , switched to M , same result , tried A , S, Auto ... all the same result ! I noticed that the Exposure compensation symbol in viewfinder was blinking ! Was on Auto ISO and 300 was chosen ( very cloudy and dark ! ) ... so switched to 600 ..same result .
Took out lens and cleaned contacts , no difference ... tried with pop up flash and SB600 , same results .. some one suggested to go to menu and re set to factory settings .. did this with no difference .. Though unknown to me this switched from Raw to JPEG ... so the rest of the day was on JPEG ... went home to process the images ... Noticed the Raw's had lots and lots of noise , with the quality of lousy JPEGS ! .... The Camera JPEGS seemed to be much better though with camera Shake !! Next morning I found that there was another way to factory reset ... Press Qual and Exposure comp buttons together for a few seconds ... Yay ... this seemed to so the trick and now restored to it's former glory !! but on checking the PPI ( DPI) on latest images .. some were 100 and some were 240 ... before this problem they were always 240 .. By the way I forgot to mention that during all this problem , I took the photo of the girl in the cafe , very poor light and through a dirty window .. and it came out perfect !!