Optics & Waves
Basic

Lens Power

Optical power in dioptres (f in metres).

Formula

P=1fP = \frac{1}{f}

Variables

fFocal length (m)

Example

f=0.5m ⇒ 2 D

Did You Know?

Optometrists measure lenses in dioptres, the reciprocal of focal length in metres, so stronger lenses have shorter focus.

lenspowerdioptre