Deflected by the lens
December 28th, 2009
Equipment: a convergent lens with focal length included between 20 and 60 mm. In the fields of the production and the market of eyeglasses, instead of focal length people prefer speak of lens power, measured in diopters. To determine the focal length of a lens. Focal length is the distance from the lens node to the point at which a ray, which was initially parallel to the optical axis, intercepts the axis after being magnifying lamp deflected by the lens. Magnifiers are inspection instruments that are used to magnify a product or part detail via a lens system. The nodes of real lenses and their distance are neglected by thin lens formulas and this leads to some errors.
Entry Filed under: Miscellaneous