Telecentric lens Field of View (FOV) refers to the lens can cover or observe the size of the field of view range, specifically, the optical center of the lens as the apex, the object image of the target to be measured can pass through the lens of the maximum range of the two edges of the angle formed.

In the field of optical lenses, the field of view angle is a key parameter that determines the range of the field of view of the optical instrument.

Characteristics of the field of view of telecentric lenses:

1. Smaller: Telecentric lenses, because they are designed primarily for long-range imaging, typically have a smaller field of view than standard or wide-angle lenses. For example, the focal length of about 200mm telecentric lens, its field of view may be about 12 °, and longer focal length (such as 300mm or more) of the super telecentric lens, the field of view may be further reduced to about 8 °

2. Clear imaging: telecentric lenses through its special lens combination design, can be in a smaller field of view to achieve a clear long-distance imaging effect. This design helps to reduce image aberrations and distortions during long-distance shooting, ensuring image clarity and accuracy.

3. Application Scenario: Due to its advantage of long-distance imaging, telecentric lenses are widely used in fields requiring high-precision observation and measurement, such as microscopes, telescopes, high-precision photography, and industrial automation inspection.

Relationship between field of view and focal length:

There is a relationship between the field of view and the focal length of the lens. In general, the longer the focal length, the smaller the field of view; the shorter the focal length, the larger the field of view. This relationship can be roughly estimated by the following formula:

\text{image height} = \text{EFL} \times \tan\left(\frac{\text{FOV}}{2}\right) \] where EFL is the focal length and FOV is the field-of-view angle (in degrees). It can be seen from the formula that for a given image height, the longer the focal length, the smaller the field of view required to achieve the same image height.