Multiple exposure to reduce noise and gain detail

I was at McDonald's having an ice cream and I noticed the smoky sky turning into an interesting sunset. I took my iPod Touch out of my pocket and held it to the glass. Knowing what sort of horrible quality I was going to get, I took several identical shots to see how much improvement I could make with some editing. I took about 20 shots, but for editing I used 9 of the least awful shots. The first shot is a single exposure, the other is the combined 9 with a bit of additional noise reduction and some sharpening. All 9 shots were as horribly awful as this "before" picture. I think it's pretty amazing that in combining a bunch of terrible shots you can get something much better than any one individual shot.

This technique not only reduces noise. It increases detail as well - all other methods of noise reduction that I know of cause some degree of detail loss. It is nearly impossible to see some of the power lines in the upper right of the first picture, but in the second picture you can see them well enough to count them. It's still not quite possible to read the license plates, but you almost can. The sky is a lot less noisy. The same for the parking lot, and notice that the edges in the concrete are sharper and the brick detail at the extreme right is much better. Even the edited shot is pretty bad, but compared to a single shot it's a big improvement.

Using this terribly noisy camera gave me a good chance to demonstrate how much of an improvement you can make with shots that could use better detail and less noise. Think what this technique can do for a dedicated camera! And more so if you're shooting RAW. (What you see here is .jpg from start to finish)

(Click to enlarge)