Colorful Aurora

The aurora last night was amazing, but for a short period, the colors were really intense.

Note: the colors were not this intense to the naked eye. I could just make out the red and greens. The camera sensitivity was jacked up pretty high to capture the colors and details, and I also took very long exposures, up to 30 seconds, to get as much color as possible.

I also experimented with boosting the image brightness by raising the ISO value for the exposures. The smoothest images had an ISO setting of 200, with 30-second exposures. The noisier-looking images had ISO settings of 1600 and 3200, which allowed shorter exposures to show more details.

Low ISO, 30-second image shows rich colors, especially purple.

The ISO setting for the image above was 200. The colors are very rich. But color is not the only thing that changes with higher ISOs; I was able to use shorter exposure times at high ISOs, and this reveals more details. (The aurora was constantly moving and shifting, so the low-ISO images are long enough to blend those movements and thus obscure details.)

High ISO, 4-second image shows noisier colors but more fine details.

The above image was shot at ISO 3200 (a gain of four stops), and you can see lots more small-scale details. The exposure was only 4 seconds. However, there is some loss of color richness; the purple at upper left is noticeably weaker.

I will add another post with a bunch of the high-ISO images to show the changing details.