I was trying some long exposures the other night in my backyard to practice the technique as I plan on driving about 20 miles out of town to get some star trail pictures soon. I had long exposure noise reduction turned on and noticed it took the same time as the original exposure to finish processing, so a 30 minute exposure took another 30 minutes to process. This brings up a question as I will be snowshoeing near the Cascade Mountains when I take my star trail picture(s).
If I take a one hour exposure on the bulb setting, will I be able to move the camera and put on the lens cap while it is taking another hour to do the long exposure noise reduction. I would rather head back to my car instead of waiting another hour in the snow until it finishes if possible. If this is not possible, is there something I can do in post processing that will take the place of using long exposure noise reduction in camera? I am using Lightroom 4 for my post processing. Thanks.