In low light, naturally, noise becomes an issue along with slower shutter speeds giving you blurry pictures and it is slower to focus. (pocket-lint.com)
If you want absolutely everything in focus or a really slow shutter speed, you can use an aperture narrower than f / 16. (howtogeek.com)
The best way to show this is to deliberately slow your shutter speed down. (howtogeek.com)