The relationship between secondary spectrum and photography

We all hope to get true colors in photography, especially color photography. Almost all modern photographic lenses can correctly record the same color seen by human eyes on film. When the film shot with a long focal length lens is enlarged, you will see that the edge of the subject is surrounded by colored spots, which reduces the clarity and resolution of the photo, which means that there is chromatic aberration in the lens.

Therefore, for long focal length photography system, the most important thing is to correct the secondary spectrum, that is, apochromatic. In this paper, we will start with reducing the secondary spectrum of the long focal length photographic system and design the long focal length apochromatic optical system by PW method.