Optical Lens Calculator v1

Price: £19.06 (£19.06 Inc. VAT)
Calculator for the performance of optical lenses


An optical lens concentrates light that has passed through it magnifying or shrinking the projected image of an observed object by an amount dependent upon; the distance between the lens and the object, and the shape of the lens.

The direction of a ray of light through a lens is governed by Snell’s law, which is dependent upon the refractive indices of the lens material and the the environments on either face. An optical lens is normally, but not necessarily, made of glass and the environments are normally, but not necessarily, air or a vacuum.

Either or both faces of a lens are normally spherically concave or convex (or even flat), the radii of which will determine its performance.


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Lenses allows you to enter a radius for each face of the lens (positive for convex and negative for concave) a lens thickness, the direction and position of an entering light-ray, a distance to the object being observed and refractive indices for the lens material and the environments on both surfaces.

The lens calculator provides details of the path of the light-ray through the lens, the principal planes and points within the lens, its focal length and its limiting optical diameter (above which parallel light will be reflected internally). The lens calculator also provides an active image of the lens and the light-path through it.

For help using this calculator, see Technical Help

Combined Stress Calculator - Options

Combined Stress

Combined Stress converts uni-directional stresses into their various 3-D equivalents along with their orientations.

You enter: and the combined stress calculator will provide:
  • Radial distance of entering light-ray
  • Angle of entering light-ray
  • Spherical radius of front face
  • Spherical radius of back face
  • Lens thickness
  • Refractive index of lens material
  • Refractive index of environment at front face
  • Refractive index of environment at back face
  • Distance to observed object
  • Angle of incidence of entering light-ray
  • Angle of incidence after entering
  • Angle of incidence before exiting
  • Angle of incidence after exiting
  • Angle of light-ray within lens
  • Horizontal distance between the secondary principal point and intersection with lens axis
  • Radial distance of exiting light-ray
  • Angle of light-ray on entry about spherical radius
  • Angle of light-ray on exit about spherical radius
  • Horizontal distance between front face and primary principal point
  • Horizontal distance between back face and secondary principal point
  • Focal length according to Snell’s law
  • Focal length according to standard formula
  • Focal length according to standard (n₁=1)
  • Lens power
  • Lens magnification
  • Distance from secondary principal point to image
  • Maximum physical diameter
  • Maximum optical diameter

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