Lens Distortions

[dylanframes]

I've started practicing image editing on photoshop just recently and I want to know what is barrel and pincushion distortions?
Thanks in advance. :)

[dylanframes]

Still no response about my query? Hmmm.........

[Max]

Definitions:

Barrel Distortion -
An aberration of optical systems, in which magnification decreases with distance away from the optical axis. With such a system, squares are imaged with their sides bulged out, looking sort of like barrels. (Actually, the points of the squares are imaged a little bit less far out than where they ought to be, because of the reduced magnification in the outer part of the field.)

Pincushion Distortion -
An aberration of optical systems, in which magnification increases with distance away from the optical axis. With such a system, squares are imaged with their sides curved inward, looking sort of like pincushions. (Actually, the points of the squares are imaged a little bit further out than where they ought to be, because of the increased magnification in the outer part of the field.)

Here's a free Photoshop plugin to correct those distortions:

http://epaperpress.com/ptlens/