Hi guys and gals, I was looking over some info on pinholeresource.com, when I noticed an ad for something called the "Apo II Pinhole/Zone Plate Shutter". http://www.pinholeresource.com/agora/agora.cgi?cart_id=%%cart_id%%&xm=on&p_id=00011 I had been thinking of buying an old shutter on eBay, and jerry-rigging it to work with a brass pinhole on my 5x7 camera, but if this thing is everything it looks to be, this may be a much better way to go. Do any of you know anything about this pinhole shutter? Any comments, good or bad? Also, can anyone tell me what a zone plate is, and how it differs from a pinhole? Thanks!