Focus Adjustment for Metal Camera

[Ari]

Hi,
I recently bought a Kodak Master 8x10 and noticed that my last few negs have been slightly soft, specifically the camera seems to focus just slightly behind the spot where I am focusing.
I did a crude measurement using a digital calliper, and found that the GG needs to move slightly closer to the film plane.

I've read about using shims on wood cameras, but never read about moving the GG closer on a metal camera.
It being a metal camera, I am hesitant to start filing it down, but maybe I shouldn't be too concerned.

Any thoughts on the best way to proceed?

Thanks in advance.

[Mark MacKenzie]

I think I would adjust your film holders before doing any permanent damage to a camera.

[evan clarke]

I think I would adjust your film holders before doing any permanent damage to a camera.

IMHO, don't mess with the holders, they should remain standard for use on other cameras. I would pull the GG and see if there are shims under it. Is it installed with the ground surface to the inside??

[Ari]

Mark, I agree with Evan: the film holders should remain untouched.
Evan, there are no shims under the GG, and it is installed properly.
It seems the ideal solution is to find a machinist well-versed in camera mechanics.

[Mark MacKenzie]

I am definitely talking out of my hat (without experience) but my thinking was that for an 8x10 people usually only have a few holders. Surely there is some procedure from Kodak to adjust for this. Using a file on the camera seemed pretty radical. Good luck with it!

[Ari]

Is there anything stuck to the bottom side of the GG frame that might be preventing it from sitting tight against the camera back? Are the springs still tight? These cameras were pretty well machined by Kodak and shouldn't need any additional work. It is possible you got a lemon, but I imagine the previous owner would have had the same issue.

Thanks, Greg; no, I cleaned everything off, and there are no obstructions under the GG.
Springs have already been tightened by me, and the film holder rests snugly when inserted.
The previous owner never used the camera, and in my test shots before buying, I wrote off the slight softness as movement on the sitter's part.

[Jac@stafford.net]

The Kodak Master is my most accurate 8x10 camera. I second the suggestion to check to be sure the ground glass faces the lens.

Some lenses shift focus when stopped down. Did you check focus stopped down?

[Ari]

I didn't stop down, I shot wide open; ground glass is properly installed.
Thanks

[Brian C. Miller]

Ari, from what you've described, the film plane is closer to the lens than the viewing plane of the ground glass. How is the GG installed? Is the ground side of it facing you or the lens? If it is facing you, then turn it around towards the lens, and then you can shim it back out to where it needs to be.
Now, it could be that for the age of your camera, the holders were wooden and made by Kodak. So it could be that your camera is correct for the matching Kodak holders. You can experiment with a holder by gluing bits of film on the edges with a removable glue like Elmer's white glue. Do that with one holder, and after you're done then you can just remove the shims with water.
There is another option, of course. Use a soft portrait lens wide open, and then you can always point to the lens and the most obvious culprit.

[C. D. Keth]

Is there any slop or wiggle in the rear standard when it's locked down? I recently bought an 8x10 master view and it was quite sloppy and had to be fixed to really be useable. If yours needs help, I can send photos of what I did to fix it. It's doable with hand tools, I don't know your workshop/handiness situation.