Kurt Norlin wrote: "I ran into this the other day, and thought list members might find it interesting.
http://www.qualitycamera.com/zone%20plate%20.htm " This appears to be the site for the manufacturer: http://www.softropolis.com/PTG/ they say the ZP is f/128 and the PH is f/512, while the figures at QC are f/256 and f/512. I guess the manufacturer's figures are the right ones.
