Magnifiers Lens

Magnifiers are used to "magnify" objects. The magnifying power depends on the focal length of the lens. The larger the focal length, the less is the magnification. As the magnification increases , the field of view decreases and the lens diameter also decreases.

Magnifiers can be of many types. A simple plano convex lens is also a magnifier but has a limited performance capability. It is useful for general viewing and small magnifications.
Two lenses with an air space in between give a slightly better performance in terms of field of curvature.
Triplet lenses are preferred for high magnifications and they give very good performance in terms of flatness of field, distortion and distortion. They are used for inspection of very small objects.

Astro manufacturers simple as well as compound type of magnifiers. Some of the triplet magnifiers are shown below.