How to protect a groundglass in transit?

**Dan Fromm** · 27-Jan-2018, 13:36

Bob, since we focus on the ground side of the glass, not the shiny, and since the ground side is supposed to fit snugly against the back why should thickness matter?

**Jimi** · 27-Jan-2018, 13:47

Thanks, Bob - the thought about the thickness of the groundglass also crossed my mind ...

I don't have my micrometer here, so I can't measure the thickness at the moment of the three specimens I have here. It could well be that the groundglass that broke was not an original one, although it looks like it. It is for a Sinar Norma 13x18 (1961). Apart from the thickness of the GG itself, in this particular case I can't see any way to adjust anything, apart from seating it correctly in the upper/lower grooves.

**Jac@stafford.net** · 27-Jan-2018, 14:02

Originally Posted by Dan Fromm

Bob, since we focus on the ground side of the glass, not the shiny, and since the ground side is supposed to fit snugly against the back why should thickness matter?

I'm surprised you don't do aerial focusing, Dan.

**Bob Salomon** · 27-Jan-2018, 14:23

Originally Posted by Dan Fromm

Bob, since we focus on the ground side of the glass, not the shiny, and since the ground side is supposed to fit snugly against the back why should thickness matter?

Because on his camera the new gg was so thick the repairman turned the screws that repositioned the film plane position to make them fit on that camera.

**Dan Fromm** · 27-Jan-2018, 15:38

Originally Posted by Jac@stafford.net

I'm surprised you don't do aerial focusing, Dan.

I can't do it consistently enough.

**Dan Fromm** · 27-Jan-2018, 15:42

Bob, thanks for the explanation that I don't understand. It must be a Linhof thing. With my Graphics, Cambos and former Calumet CC401 the GG lives in the focusing panel. The film holder slides between the focusing panel and the camera's back. I've swapped GGs, never had to adjust anything or do anything to the back.

As I said, it must be a Linhof thing that I just can't grasp.

**Bob Salomon** · 27-Jan-2018, 16:07

Originally Posted by Dan Fromm

Bob, thanks for the explanation that I don't understand. It must be a Linhof thing. With my Graphics, Cambos and former Calumet CC401 the GG lives in the focusing panel. The film holder slides between the focusing panel and the camera's back. I've swapped GGs, never had to adjust anything or do anything to the back.

As I said, it must be a Linhof thing that I just can't grasp.

Linhof 69 thing.