With newer cameras, a better signal to noise ratio, in plain language, means you can get respectable images in almost pitch darkness.
I took these shots in a very dark mud and straw hut in Mexico. The light level was so low that it took a few seconds to adjust to the darkness. There was no artificial light and the only light was from a small window to the left of the kitchen. At an ISO of 400, my first image was a disaster–
Initial image as soon as I walked into the hut.
Cranked up the ISO to 800. Still not good enough (notice the lady’s hands).
The last image is what I wanted to show anyway– the tortillas.
The maker’s hands in the background completes the story for me. It reflects what I consider my personal style of photography, up close and to the point.