There are many ways in which the performance of a lens can be characterized, most of which measure
properties of the in-focus image. The current work instead centers on measuring properties of an out-of-focus
(OOF) image. The image created by imaging a point of light is commonly known as the point spread function
(PSF). We have found that by measuring the OOF PSF a great deal of otherwise unavailable information about
the lens can be obtained.
The current work presents observations and sample images from measurements made on a collection of over 125
lenses. A variety of the attributes than can be obtained from study of OOF PSFs, and some of their applications,