I is for ISO

You can take sharp shots in dim light by boosting the ISO setting. The downside of doing this is increased noise in the image, but a noisy picture is better than none at all! Even better, much of it can be suppressed with careful processing.

If you shoot in raw mode, you can minimise the appearance of noise with Adobe Camera Raw or Lightroom. By zooming in tight and gently nudging up Luminance and Color in the Detail panel, you can smooth out the grainy speckling and blotchy colours that noise creates, and produce a good-looking image.