Chapter | 10 |
An understanding of residual aberrations (errors) is useful in describing the types, merits and imaging limitations of camera lenses. An ‘ideal’ lens forms geometrically accurate images but actual lenses, especially simple ones, do not since the refractive index of glass varies with wavelength, lens surfaces are usually spherical in shape and because of the wave nature of light (see Chapter 2). These cause respectively chromatic aberrations, spherical aberrations and diffraction effects. The degrading effects usually increase with both aperture and angle of field.
There are seven primary chromatic and spherical aberrations. Two ...