newbie question!!

[bopins]

hi all.

I have seen the term "pin cushion" used alot when talking about lenses and pictures.
could someone please shine a torch on this meaning for me.

thanks Ben.

 

[Flamez]

A distortion that causes images to be pinched at the centre

 

[bopins]

thankyou philip.

 

[HoppyUK]

The opposite of pincushion is barrel distortion. You only see it at the edges of the frame, with straight lines that appear curved - the horizon/sea, tall buildings etc.

Many short and standard-ish focal length zooms typically show barrel distortion at the short end, running through neutral to mild pincushion at the long end.

 

[barryhennessy]

Here's a good description, check out the image, particularly the edges.
http://www.dpreview.com/learn/?/Glossary/Optical/Pincushion_Distortion_01.htm

-Barry