Lens (optics)#Lensmaker.27s equation

The lens grinder formula, lens -maker equation also indicates how the power of a thin spherical lens with its associated form. The shape of the lens is taken into account by the radii of the spheres that form the surfaces of the lenses. Other sizes, the influence on the refractive power, the thickness of the lens, the refractive index of its material and the refractive index of the surrounding medium.

There are

  • The sphere radii (It is important to note that the two radii then have the same sign if the center points lie on the same side of the lens [ convex- concave lens ], but different signs when the lens is biconvex or biconcave; see also: Spherical lenses),
  • The thickness of the lens ( measured at the height of the optical axis ),
  • The refractive index of the medium outside the lens,
  • The refractive index of the lens material,
  • The focal length of the lens and
  • The refractive power.

For optical systems with the same media object in space (1) and image space ( 2) () is generally:

Is under the same conditions, the external medium is air to a first approximation:

For thin lenses whose thickness is much smaller than its diameter, the equation for the so-called lens-grinder simplified formula:

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