LensMaker app for iPhone and iPad

The Lens Maker Equation App formulates the focal length and power based on the proposed lens shape. The radii of curvature and lens thickness will determine the lens shape. The focal length is the distance from the lens at which the light comes to a point. The reciprocal of the focal length is the lens power, commonly known in eyeglass prescriptions and measured in diopters.

For a very thin material, the thin lens approximation will often suffice. This will allow the lens parameters to be determined without the thickness of the material to be known. The technique may be used when the radii of curvature are much greater than the thickness of the lens. Normally, this equates to the radii of curvature being more than 10 times the lens thickness. To use the app, input the values of radii, thickness, and refractive index, to get an approximate measure of the focal point and power.