Georgia State University
Georgia State University: Hyper Physics: Lens Maker's Formula
A discussion of the lens-maker's formula and its use in determining the effect of lens shape and index of refraction upon the magnifying power of a lens. Includes an interactive problem-solving section.
Georgia State University
Georgia State University: Hyper Physics: Telephoto Lens
At this site from Georgia State University Physics Department the operation of a telephoto lens is discussed. The refraction of light through the lens is shown and a link to a calculation page is provided.