There's alot that go into the hyperfocal distance and how to calculate it etc. In short, the hyperfocal distance is the exact focal distance at which depth of field is maximised for a given aperture and focal-length combination.
This sounds like a mouthful, we know. But after learning about hyperfocal distance, you'll be able to estimate how much of a scene should be sharp and from what distances based on you lens and aperture choice.
Hyperfocal distance: The closest distance at which a lens can be focused while keeping objects at infinity acceptably sharp. When the lens is focused at this distance, all objects at distances from half of the hyperfocal distance out to infinity will be acceptably sharp.
Hyperfocal near limit: The distance between the camera and the first element that is considered to be acceptably sharp, when focusing at the hyperfocal distance.
As a quick example, lets say we have a 50mm lens at f1.8. Our subject is 2M away from us.
Our Depth of field will be;
Near limit 1.92 m
Far limit 2.09 m
Total of 0.17 m in sharp focus.
Our hyperfocal distance will be;
Hyperfocal distance 46.82 m
Hyperfocal near limit 23.41 m