A camera lens is an optical device with single or assembly of lenses used in conjunction with a camera to make images of objects on the sensor. There are variety of lenses available according to the need as CCTV, Machine Vision, Zoom, Macro, Micro, Standard, Telocentric etc.
The ability to quickly perform repeatable, high accuracy measurements is critical to maximize the performance of many machine vision system and would solely depend on proper selection of Lenses and Lighting apart from the needed camera and software. Lenses : Lens is a Transparent piece of optical glass with curved surfaces that transmit light and pass it to the sensor in camera Lens varieties: -Fixe d Focal lens -Vari Focal Lens -Zoom Lens & Zoom systems. -Motori zed Zoom Lens -Accessorie s like extensions and extenders -Macro lenses -Telecent ric Lenses More about Telecentric lenses: A telecentric lens allows the highest possible accuracy to be obtained in a machine vision System. Conventional lenses have angular fields of view such that as the distance between the lens and object increases, the magnification decreases. This is how the human vision behaves, and contributes to our depth perception. This angular field of view results in parallax, also known as perspective error. But Telecentric Lenses eliminate the parallax error characteristic of standard lenses by having a constant, non-angular field of view; at any distance from the lens, a Telecentric Lens will always have the same field of view. The primary advantage of a Telecentric Lens is that its magnification does not change in respect to depth. Another advantage of using Telecentric Lenses in metrology applications is that Telecentric Lenses typically have lower distortion values than Fixed Focal Length Lenses. Telecentric Lenses provide a good alternative to Fixed Focal Length Lenses due to their low distortion and invariant magnification. The distortion, coupled with the parallax error inherent to non-telecentric lenses, makes the pins toward the edge of the image appear as though they are bent toward the center. This is eliminated by using the Telecentric lenses. Telecentric are available as Bi Telecentric lenses also. Bi-telecentric lenses that help to maintain accurate measurements, even when the object starts to move out of focus. bitelecentricity makes these optics true telecentric: no magnification change occurs when the object is moved from its nominal working distance as the ray slope in image space remains unchanged. Navitar, Moritex and Opto Engineering brand Telecentric lenses are provided by the company by making a proper selection of telecentric lenses according to the budget and project. Telecentric illuminations are also available to help telecentric lenses work better to give more accurate results.