Lens Types

Virtually all cameras need a lens of some kind to collect the light that is scattered from the surface of an object. When choosing a lens for a specific application they can be classified by five main factors which are: Mount, Focal length (or focal range for a zoom lens), F-​Number (aperture), Image quality (resolution & distortion), Image circle (maximum sensor size).

Standard lenses that focus to infinity are very good when inspecting large components, but when objects are comparable in size to that of the imaging sensor, Macro lenses are the best choice. Macro lenses are not specified in terms of their focal length, but are named according to the magnification: the FOV being proportional to the sensor size and the magnification factor alone. These lenses generally have a fixed working distance and a fixed iris. Although inflexible, these lenses provide very high levels of magnification and distortion is kept to a minimum.

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