Finite Imaging; When Focusing to Infinity Doesn’t Cut it.
Many applications require that CMOS or CCD imaging lenses be optimized for a finite object, that is, for an object distance closer than “infinity.” The practical definition of infinity varies based on individual use-case requirements and specific lens being used. It can be defined in different ways, such as spot size, through-focus MTF, etc. As a general rule of thumb, and depending on F/#, infinity is generally 100-200x the focal length (EFL) of the lens…