Super Graphic - where to measure bellows extension

Hi, I've got hold of a Graflex Super Graphic and I'm figuring out how to use it before actually putting any film through it (can't really develop 4x5 yet, as I've got to improve the blackout in the darkroom...)

Got a copy of Using The View Camera (Simmons) and have a question about measuring bellows extension - in general and for exposure factor in closeup shots. What part of the lens to you measure from?

I thought I'd work it out by focussing at infinity and seeing if that made it obvious, but measuring to the film plane to the lens back seems to be 14-15cm rather than the 13.5 that I was expecting for the 135mm lens.

Have I got something wrong, or am I expecting accuracy which isn't needed here?

Cheers

It's not over critical, take the measurement from the centre of the lens/shutter, if its a modern Copal roughly where the flash sockets located.

I marked the factors on the rail of my Wista with a black indelible felt tip 22 years ago and its still there.

Ian

This may be of interest for exposure compensation:

http://www.salzgeber.at/disc/index.html

Also, check in the "Library" on this site for a similar tool (Bellows Target&Ruler):

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