Hyperfocal distance is the focussing distance that gives your photographs the greatest Depth of Field (DoF).

The definition is the closest focussing distance that allows objects at infinity to be acceptable sharp.

When a lens is focussed on the hyperfocal distance the depth of field extends from half that distance to infinity.

The mathematics are:

H =   f²/ (N* c)

Where:

    H = Hyperfocal Distance

                f = focal length of lens(mm)        

                N = Aperature (f stop)

                c = Circle of Confusion

Example 1 : Full frame camera with a 50mm lens set at f8

H  =  (50 *50)/(8*0.033)= 9470 mm = 9.47 metres

Example 2 : Full frame camera with 20mm lens at f11

                                H = (20*20)/(11*0.033) = 1212.12mm = 1.2m