How to check Rolleiflex film plane focus, when the tripod mount is part of the back (that's removed)?

[Sharktooth]

I'm doing a repair on a Rolleicord, since the viewing lens had not been properly positioned on a previous repair. There's a problem checking the focus on the film plane, since there's no way to hold the camera securely once the back has been removed. The tripod socket is part of the back, and the back has to be removed to view the focus at the film plane with a piece of ground glass.

The only way I can think to do this, is to put the camera on a table, and then try to get the ground glass and a loupe onto the film plane. The camera can still move around on the table, and it really needs about 3 or 4 hands to do this securely (which I don't have).

Has anyone figured out a good way to hold the camera securely on a tripod, when there's no tripod socket on the camera? Some genius must have figured out how to do this at some point over the last 80 years. Looking for that genius. Please step forward, and announce your geniosity!

 

[Dan Daniel]

Put a table on the tripod, and then put the camera on the table!

I'm sure that you could build a jig, many options, to hold the camera.

And what about being on the edge of a table where you can kneel down and look at the ground glass doesn't work for you? You can put tape or other marks on the table to mark the position. Clamp a board to the table as a stop?

 

[campy51]

You can do it but it's a pita.

 

[blee1996]

I normally just put TLR side ways on a table, with some friction mat or blu-tack underneath to make sure it stays put.

To calibrate focus on TLRs, typically you only need to adjust infinity. I use ground glass (with a cross hair on the matte side), and a mirrorless digital camera with telephoto lens focusing to infinity. You can search youtube for tutorials: dead simple and fast. Takes 5-10 minutes to get it done, and all can be done on a workbench indoors.

 

[JensH]

The only way I can think to do this, is to put the camera on a table, and then try to get the ground glass and a loupe onto the film plane. The camera can still move around on the table, and it really needs about 3 or 4 hands to do this securely (which I don't have).

Yes, that's how I do it. Camera on a glass table in the garden, free view to some trees 2 km away. As distance is that much, I don't care if the camera moves a tiny bit.
First I focus in the image plane (by ground glass and a loupe, as you say), then the finder lens is corrected/adjusted without touching the focus knob until the image in the camera ground glass is right.

 

[Sharktooth]

No genius awards yet, but everyone deserves a participation ribbon! Thanks.

 

[ic-racer]

One would use an autocollimator. I set focus to the actual film I’m using, usually Ilford HP5.