Mark IIn long exposure issues?
Last night I took some long exposures (10 sec) of a torchlight parade done on ski slopes. The image on my LCD was perfect. Plenty of ambient light to illuminate the slopes and the mountains and a really cool snaking red light down the middle of the slope. When I downloaded the images this morning, they had gone totally black except for the torchlight. In DPP I increased the exposure 2 stops to get back the slope and mountain detail. The noise in the image is terrible even with NR on. All shot in RAW. Some of the jpegs I shot actually looked quite a bit better with no noticeable noise.
Any ideas why the LCD thumbnail and the downloaded image would look so drastically different?