Re: Smarter material for ground glass shim?
Quote:
Originally Posted by
maltfalc
grain and fresnel lines are right against each other on a crown graphic.
Then the fresnel is upside down. The grooved side faces the lens. Not the gg.
Re: Smarter material for ground glass shim?
With a razor knife, cut up some sections of a pop-sickle stick for shims, then always shoot at f/16 or smaller :)
Heck, I think I cut some small strips of mat board many years ago and used that for years as shims.
I think I just held the edge of the Fresnel against the edge of the mat board scraps that I had and it looked right.
Re: Smarter material for ground glass shim?
Quote:
Originally Posted by
Bob Salomon
Then the fresnel is upside down. The grooved side faces the lens. Not the gg.
not on a crown/speed graphic. grooves against gg so the fresnel doesn't shift the focal plane or soften the image and the grooves are protected from scratches.
Re: Smarter material for ground glass shim?
Quote:
Originally Posted by
maltfalc
not on a crown/speed graphic. grooves against gg so the fresnel doesn't shift the focal plane or soften the image and the grooves are protected from scratches.
The only way the fresnel can shift the film plane if the camera wasn’t designed for a fresnel under the gg.
Since the groves face the lens you can’t scratch it.
Re: Smarter material for ground glass shim?
Quote:
Originally Posted by
Bob Salomon
The only way the fresnel can shift the film plane if the camera wasn’t designed for a fresnel under the gg.
Since the groves face the lens you can’t scratch it.
it was designed for a fresnel under the gg with the grooves facing back so they don't get scratched by film holders or when the back is removed. i'm tired of repeating myself. i don't care how you THINK graflex SHOULD have built the camera, that's not how they built it. fresnel goes in with grooves against gg. end of discussion.
Re: Smarter material for ground glass shim?
Quote:
Originally Posted by
maltfalc
it was designed for a fresnel under the gg with the grooves facing back so they don't get scratched by film holders or when the back is removed. i'm tired of repeating myself. i don't care how you THINK graflex SHOULD have built the camera, that's not how they built it. fresnel goes in with grooves against gg. end of discussion.
Care to explain how inserting a holder can possibly scratch the fresnel?
Re: Smarter material for ground glass shim?
Quote:
Originally Posted by
Bob Salomon
Then the fresnel is upside down. The grooved side faces the lens. Not the gg.
maltfalc is correct - my Crown Graphic had the fresnel lens installed facing rear towards the ground glass. The engineering nomenclature I discovered on graflex.org seems to confirm these were in fact intended to be installed this way. Contrary to what one might be familiar with on, perhaps, a Linhoff.
Re: Smarter material for ground glass shim?
Quote:
Originally Posted by
maltfalc
your numbers don't sound right. the original gg and fresnel should both be 1/16" (1.6mm). frame depth should be 2/16" (3.2mm).
No doubt. I once had a Starret depth guage, but it was taken from my garage years ago. I'm now reduced to using a cheap treadwear gauge to do a basic go/no go comparison with a film holder with a sheet of film loaded.
Re: Smarter material for ground glass shim?
Quote:
Originally Posted by
Bob Salomon
Care to explain how inserting a holder can possibly scratch the fresnel?
depends on the holder. calumets are notorious for it.
Re: Smarter material for ground glass shim?