I tried my first hour long exposure last night and I found out that after shooting this shot for 1 hour it takes the 5D2 another hour to process the in camera noise reduction before you can do anything else. For a moment I thought I broke my camera where I made a spur of the moment judgement call to shut it down after about 45 min and it kept going to my surprise. I was then going to pull the battery but decided to read the manual where it stated when using the camera in bulb mode with noise suppression activated that the processing can take as long as the initial photograph. Whew, OK then, I was glad to know that I did not break it but this is a major pain or draw back however you choose to look at it. Even with the long exposure noise control set to auto I can see noise issues so if I didn't use the noise reduction setting it would most likely be a pretty messy scene.