Pentagonal prism is a pentagonal prism, which has two important characteristics: first, although the light turns 90, the image plane has neither rotation nor specular reflection; Second, it is a fixed steering angle device, that is to say, all lens rays are turned by 90 degrees, so pentagonal prism is a key component of rangefinder and can also be used in SLR camera. The reflective surface of the prism is protected by AI + black paint.
