Because both convex surfaces contribute to the magnifying power, these lenses are available with useful for collecting and refocusing light from a small beams in applications where the length of an optical train spot quality, you should use two lenses; one to collimate the diverging beam, and the second to focus the collimated beam to a small spot.
The lenses are primarily used for imaging at close to 1:1, illustrates their function. The convex surfaces of approxi- mately equal to the radius of curvature. The lenses have very low optical aberration at magnifications from 5 to 0.2.At these magnifications, coma, distortion, and chromatic aberrations are minimal.
Standard BK7 Double Convex Lenses
