Defocus aberration
Videos
In optics, defocus is the aberration in which an image is simply out of focus. This aberration is familiar to anyone who has used a camera, videocamera, microscope, telescope, or binoculars. Optically
A photograph of Christmas lights with significant defocus aberration
Point spread function
Videos
The point spread function describes the response of a focused optical imaging system to an idealized point source of light. In casual terms, for a given camera, it is the blurry blob image captured fr
A point source as imaged by a system with negative (top), zero (center), and positive (bottom) spherical aberration. Images to the left are defocused toward the inside, images on the right toward the outside.
The point spread function of Hubble Space Telescope's WFPC camera before corrections were applied to its optical system.