Glossary
Hyperfocal distance
The closest focus distance that keeps infinity acceptably sharp at a given aperture.
Focus at the hyperfocal distance and your depth of field will run from half that distance to infinity. This is the trick for landscape and street photography when you want the whole frame sharp without fiddling with focus. The app's hyperfocal calculator tells you the right distance to set on the lens for your focal length and aperture.