Spherical Lenses: High Quality Optics for the Professional

Double convex lenses feature two convex surfaces with equal radii and both horizontal and vertical symmetry. They are ideal to form an image at close conjugates as well as for image relay. At 1:1 magnification, when object and image distance are equal, the symmetry of this lens mean that coma, distortion and chromatic aberration are cancelled out and spherical aberration is minimized. We recommend double convex lenses for applications where conjugate ratios are between 5:1 and 1:5.

Magnifying glasses typically use double convex lenses. When the object distance is close, the rays will be bent toward the focal point at the center of the lens. This causes the virtual image to appear much larger than the real image.

Plano concave lenses have negative focal lengths, and are appropriate for situations where the light rays should diverge after passing through the lens. For instance, in light projection, in beam expansion, or when one wishes to expand an optical system’ focal length. When used with other lenses, the negative spherical aberration can be used to cancel out aberrations created by convex lenses. These lenses feature one flat surface and one that is concave, and in most situations, the curved surface should face the largest object distance. The one exception is in high energy lasers, where the flat surface should be directed toward the infinite conjugate or largest object distance in order to avoid the possibility of a virtual focus.