Night Photography Exposure Theory

A friend recently asked me if the old adage of “expose to the right” still holds true for Night Photography. It’s a good question, and seemed like a good topic for my first blog post in a while.

astro-landscape photography histogram

A pretty decent Astro-landscape photography histogram

Different types of night photography require different exposure strategies. For astro-landscape photography like images of the Milky Way, try to get the histogram off of the left side of the frame- just a gap between the left edge and shadow portion of the histogram. You have to push the camera to the threshold of its capabilities, so that’s about the best you can hope for. At high ISO, maximum aperture, and shutter speed limited by apparent stellar movement, a right-biased histogram is not a reality. Fortunately, an increasing number of  cameras can stand up to the high ISOs like 6400-12800 that this type of work requires.

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A good full moon exposure histogram SOOC

For Full moon exposures shot at near native ISOs, it’s still a good idea to push the histogram a bit further to the right. Just be careful not to make it so bright that you cannot bring it back down in post. The idea here is to increase image quality by making sure the shadows are as clean as possible without blowing any highlights. The key to this type of night photography is finding the right balance between ambient, and added light. I generally reduce the ambient exposure by 1-3 stops relative to my light painting. Remember that the height of the histogram is irrelevant. It’s how the tonalities extend across the horizontal axis that count. So if your shadows are well off of the left edge and are rather tall, and your highlights extend almost to the right edge of the histogram, but barely get off of the floor, you are doing it right.

About the best histogram you can hope for in urban situations.

About the best histogram you can hope for in urban situations.

With urban night photography, the best approach is to give an image as much exposure as possible without clipping important highlight detail, by using the blinking highlight indicator rather than the histogram. Newer cameras- especially ones like the D750 do a great job at controlling noise when you bring up the exposure in an underexposed image. This technique didn’t work with older cameras. The key to successful urban night photography is to determine just which highlights are important, and which ones to sacrifice. Generally light sources in the frame should be allowed to clip, but not to blossom out past the edge of the light itself. Flat surfaces like walls or the ground should not be clipped, as it is important to retain detail in these areas most of the time.

I hope that you find this explanation helpful. If so, you might want to join me one one of my night photography workshops this summer or fall for lots more night photography information and inspiration.