I understand that as I increase ISO, I'll increase the amount of noise in the resulting image. With a constant aperture I can decrease ISO and slow the shutter speed (assume a non-moving subject, ...
I noticed that sometimes when taking pictures with my D5100, they come out with very little visible noise with ISO 800 and up, for example this picture. It was taken at ISO 1600 if I remember ...
While purchasing a DSLR which factors should be kept in mind if your aim is to zoom your photograph to 100%, frame it, and hang it on a wall? At 100% there shouldn't be ANY noise.