Usually camera lenses are optimized for infinitely distant objects. These lenses give their best performance when an object to image distance (OI) is from 4X the focal length to about 10X the focal length.
Westech designs and manufactures finite conjugate lenses. These lenses are optimized for magnifications from 1: 1 to around 10:1. Although you may use an infinity-corrected lens at a finite distance, it will not give its best performance. You can also use a finite lens at infinity but to get the optimum performance the lens should be matched to the correct reproduction ratio.