Distortion, a frequently mentioned parameter in optical systems, is one of the key factors limiting the accuracy of optical measurement. It refers to the degree of distortion of an image formed by an optical system relative to the actual object. Distortion only causes image deformation and does not affect image sharpness.

• Positive distortion: The actual image height increases faster than the ideal image height as the field of view expands (i.e., magnification increases with field of view), so the spacing of concentric circles gradually increases from the inside out.
• Negative distortion: The spacing of concentric circles gradually decreases from the inside out.

In contrast, our BTOS telecentric optical dual telecentric lenses feature distortion of less than 0.1%—only 1/20 of ordinary lenses. This greatly improves detection accuracy and stability, reaching the measurement limits of the highest-standard optical testing instruments available today.