Lately I took a set of pictures with night urban scenes. Such a subject requires relatively long exposures and ISO should be in most cases high enough. All this stimulates noise and so, normally night photos contain a good deal of noise artefacts. To supress noise I applied some techinque that I took from my astrophoto experience and now I would like to speak on this matter.
So, for all my night shots I used tripod and took several shots from the same point and with all the same sets (typically from 5 to 10). Surely, I saved pictures in RAW format since (a) it does not use any compression and so, it does not rape any information; (b) it uses 13 bits to code brightness (for my Canon 350d) in contrast to JPEG which does only 8. 8 bits are quite enough for resulting image but... [ Read more...