Third, the optical lens is classified by interface
1.C type lens
The flange focal length is the distance between the mounting flange and the point of convergence of the parallel light of the incident lens. The flange focal length is 17.526mm or 0.690in. The installation rib is: 1in in diameter, 32 teeth.in. The lens can be used with line array sensors up to 0.512 in (13 mm) in length. However, due to geometric distortion and market angle characteristics, it is necessary to identify whether a short-focus lens is suitable. For lenses with a focal length of 12.6 mm, a line array with a length greater than 6.5 mm should not be used. If the distance from the lens to the array is determined by the flange focal length size, the lens ring is required for the object magnification to be less than 20 times. The ring is added behind the lens to increase the distance from the lens to the image, so that the focus range of most lenses is 5-10%. The lens length is the focal length / object magnification.
2.CS type lens
With a 5 mm adapter ring, a C lens can be used on a CS-mount camera.
3.U type lens
A variable-focus lens with a flange focal length of 47.526mm or 1.7913in and a mounting rib of M42×1. Mainly designed for 35mm photo applications (such as domestic and imported various 135 camera lenses), can be used for any array less than 1.25in (38.1mm) in length. It is not recommended to use a short focal length lens.
4. Special lens
Such as microscopic amplification system. Pay special attention to the difference between CS and C. When connecting different types of cameras and different types of Len connections, customize the adapter ring. Foreign countries are very expensive, and one is not as good as oneself. The main parameters and evaluation of the optical lens The main parameters are focal length, field of view, object distance, aperture, shutter and so on. The most complete evaluation of the lens is MTF (Modulation Transfer Function). However, due to aberrations (for calibration reasons), each range of the lens has an MTF value. These ranges refer to: (1) the paraxial portion, (2) the off-axis portion, and (3) the sub-portions of the above two portions in different directions when the optical system is asymmetrically distorted. Each part has its own corresponding MTF value for different wavelength ranges of radiant energy. MTF is the most commonly used and optimal indicator for evaluating imaging systems and the best indicator for guiding machine vision system integration.