I have made a 4x5 camera using aluminium extrusions called makerbeam. I have bought one 150mm 4x5 lens and have made a couple more using binocular objective lenses and old prontor shutters from vintage bellows cameras. I decided to build a through the lens meter to more easily calculate the exposure reqiired for these home made lenses and also to more fully understand the effects of filters and bellows extension and just for the hell of it.
After huge amount of trial and even more error i have succeeded in making a resonably accurate meter which fulfills the above criteria.
I will publish details of the build if anyone is interested.
Let me know.

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