A telecentric lens system is designed so that its entrance pupil, exit pupil, or both are located at infinity. This means the chief rays of light entering or leaving the lens are perfectly parallel to the optical axis. As a result, the magnification remains constant regardless of the object's distance from the lens. Machine vision and metrology heavily rely on telecentric lenses to measure parts accurately without perspective errors.
Heard on the job
If the object distance keeps shifting on the conveyor belt, we've to swap to a telecentric lens so the size measurements stay consistent.