Northern Lights photography
Long Exposure photography
Although the Northern lights require a long exposure, the object is often to reduce exposure time as much as possible to achieve a usable exposure and with minimal star trails. A usable exposure is one where you can get the desired print without introducing too much noise into the end result, which happens when you raise the levels of an under exposed photograph. In the field, it is essential to check your histogram to get an accurate idea of exposure. For me, a decent exposure is where the mountain creeps over the half way point.
The image is open in Lightroom before processing. See how the “histogram mountain” on the histogram is creeping over the half way point. The “histogram mountain” should be on the left because it is a night photograph. This tells me that it is a good exposure that will survive lots of processing without generating noise.
Clarity with flat contrast
This image was processed totally in Lightroom. The shadows were boosted just to separate them from the blacks. The highlights were reduced, just to save small areas of burn out in the brighter pats of the Aurora. Effectively this flattened the contrast of the image, but prepared it for the de-haze and clarity increases.
A poorly exposed night photograph can be so full of noise that it is challenge seeing the stars. This image has more than enough noise reduction (it would be less noise reduction if I was going to print). You can clearly see the stars, they are nowhere near being erased by noise reduction.