matte boxes - what do they really do?

[c.g._eads]

I understand the concept of matte boxes, that they block out the light from the sides and top (at least I think that's what they're for). But I'm wondering how necessary they are.

Does anybody have comparable shots - one with matte box, one without - where they can show the difference? How significant is it?

Chris

 

[puredrifting]

Matte boxes make you look ultra cool and all of the girls fall at your feet because you are then part of the camera ultra stud club.

Oh yeah, and this has what to do with lighting? ;-)

D

 

[Dan Vance]

I remember when matte boxes were actually used to hold mattes!!