I have an old portrait lens that I want to use. It came with a set of torn paper disks with verious size holes, apparently to be used as f-stops as there is no iris. The front of the lens unscrews to get at the set and select one for use. My guess is that I'll be using the lens wide open, but I'd like to make a new set of stops as well. Can anyone suggest what paper to use? Or would they be better if made from thin plastic of some kind? Should I duplicate the stop diameters or should I try to calculate new ones? If so, how would I do it? Any suggestions would be helpful. Thanks in advance.

-- Arthur Gottschalk (Arthurwg@aol.com), January 21, 2002

Answers

I don't have any more expertise than you do so take this FWIW. I would use black kraft paper, and I never re-engineer if theirs a known to compare to. That aside I think you may have an opportunity to try different variations of larger center hole and smaller peripheral holes surrounding the main sort of like the inserts for an Imagon. You might be able to achieve something very nice that way. Make a seat-of-the-pants guess at the resultant aperture and then fine tune with flash variation for portraiture. Sounds like an ideal situation for a Polaroid back.

If it focuses at infinity at 300mm (just a for instance) f11 would be near 27mm=300/11, and f22 would be 13.5=300/22 or so. If you can figure one out and line them up you'll know them all (unless 1 is missing)

Another idea, if you've got a decent drawing program in the computer, draw them all there, Paint them black with ink, and cut them out.

-- Jim Galli (jimgalli@lnett.com), January 21, 2002.

FWIW:

Maybe you should check Steve Grimes and how he makes his waterhouse stops at http://www.skgrimes.com/wat/

Regards, Jimi

-- Jimi Axelsson (jimi@earthling.net), January 22, 2002.