Focus problem Graflex Graphic view

[henk@apug]

Hello,

I am having a focus problem with my old graflex graphic view.

What I did : no tilts, no swings
Focussed on a certain point, take picture, check focus after removing film holder.
Focus check was always ok after removing film holder.

Problem : plane of sharp focus is about 7 meter before the plane I focussed on and this on every shot.
I think the ground glass is positioned ok, since this is very simple on this camera.

What could be he problem ?
Very annoying.

Thank you !

 

[henk@apug]

I want to add that I use a magnifying loop to focus

 

[Ian Grant]

Sounds like the register is out on the back, this maybe because a Fresnel screen is in the wrong place or missing.

Ian

 

[bdial]

What kind of film holders?
Any possibilities they are actually glass plate holders without an insert for film?

 

[henk@apug]

Some images
I use Fidelity Elite film holders

 

[henk@apug]

Oeps, there is apparently 1.5mm difference between the film plane
and the ground glass !

To other graflex graphic view owners, is there something between the ground glass
and the metal to which it is pressed ?

I do not understand this difference

 

[Ian Grant]

Probably a fresnel screen. Many (but not all) later Graflex cameras came with one fitted.

If the focus frame was made to have one on the inside removal puts the focus out of register.

Ian

 

[henk@apug]

Thanks Ian.

I will try to get hold of a precise tool to measure the difference and
adjust the GG or maybe put a fresnel.

Anyone knows where I could get custom made fresnel ?

I must say that in plane of sharp focus, the sharpness and detail is magnificent !
So I have to get this right, more so because I fell in love with 4x5 photography

 

[Ian Grant]

Fresnels will differ in thickness, you need to find a Grflex one.

Ian

 

[henk@apug]

I did some measurement wirh a calliper and got a difference from 1,5mm.
I found a simple way to get the groundglass rearward by this distance, did some
new tests and focus is now ok

 

[Ian Grant]

I was looking at some fresnels screens from a UK supplier (not specifically photographic) and they were 1.5mm thick so that makes sense.

Ian

 

[David A. Goldfarb]

1.5mm is about what a fresnel is typically, so that sounds right to me as well. You can just shim it until you find the right fresnel.