[LargeFormat] calculating aperture scale - an easy way?

[Timothy Atherton]

I vaguely remember Richard writing on this once, but can't find it?

Is there an easy way to calculate an aperture scale for a shutter/lens?  I
have my 210mm Kowa Graphic in a Copal #1 shutter with an appropriately
marked aperture scale.  Say I want to put a 150mm Kowa Graphic in to try it
for a while - is there
a way to come up with a scale without sending the whole thing off to
Grimes or somewhere? (I'm not talking about the actual little piece of
metal for the scale itself - I'll just use a piece of tape or some such
and mark it - rather the measurements) thanks


 timothy atherton