You want to see Fresnel lenses, you need to go to the CG Training Center in Yorktown. They have one of every size except for 3 1/2 order. Some beehives, some clamshells. Very nice display.

Previous Fresnel thread


First Order beehive and 2nd order bi-valve


An interesting 4th order lens

Dave

to add the links & pics

[This message has been edited by Dave H (edited 06-10-2000).]