Hyperfocal distance is a distance used in optics, especially photography. It is the distance at which to focus a lens to make everything from half the hyperfocal distance to infinity acceptably sharp, that is, within the depth of field. The hyperfocal distance is the product of the square of the focal length divided by both the f-stop and the circle of confusion limit chosen.
where
- H is hyperfocal distance
- F is focal length
- f is f-stop
- Cc is the circle of confusion limit
As an example, let's compute the hyperfocal distance for a 50 mm lens at f/16 using a circle of confusion of 0.02 mm (which might be acceptable for some amount of enlargement). In the formula above, we make F = 50 mm, f = 16, and Cc = 0.02 mm; then we compute F:
The hyperfocal distance is about 7.8 m.
If we focus the lens at a distance of 7.8 m, then everything from half that distance (3.9 m) to infinity will be acceptably sharp in our photograph.
External link