127 camera focusing check.

[Cluster]

I've ended up with a few 127 cameras. These are a mixed bag of single and double element lenses, all with a curved film plane.
One is almost ready to use, but with a scale focus bezel that is loose on the threaded lens mount, so the focus calibration is lost. The other has a fungus garden within, I'll remove it and try to clean it up, again the focus may be lost.
What can I use as a focus screen to set up calibration?

 

[Sangoma]

You used to get a matt laser "transparency" that worked well for checking cameras. It look like ground glass.
I still have some A4, if it is of any interest I can get the name off it tomorrow.

 

[StephenM]

And greaseproof paper used to be used for this.

 

[Sangoma]

It is called NovaSharp Laser printing Film, made by NovaTech.

I have no idea if it still exists or is available, the box has no details at all on it.

It gives a clearer and easier to see image than baking paper, though thinking about it, would it make much difference ?

 

[Cluster]

Thanks for the suggestions guys.... I found some document laminating film that has a frosty side. I think that it is the glue side that looks this way. It reminded me of the ground glass screen on my Yashicamat, so maybe it will work.

 

[excalibur2]

A bit off topic but reading this thread has given me an idea in that as I have a hand scanner (yanno red dot) for distance I could check if what I see in my SLR in focus is the same as distance on the lens, I checked a few years back with a tape measure and my old Pentax was out (guessing the mirror was slightly out, too much foam?)........Ok I have nothing better to do ATM

 

[Sangoma]

A bit off topic but reading this thread has given me an idea in that as I have a hand scanner (yanno red dot) for distance I could check if what I see in my SLR in focus is the same as distance on the lens, I checked a few years back with a tape measure and my old Pentax was out (guessing the mirror was slightly out, too much foam?)........Ok I have nothing better to do ATM

I've always taken what is on the lens as a guide only, never worried if isn't accurate, it is usually close enough for a guessed distance, especially when you have to guess you would probably select a higher f stop anyway to be on the safe side

 

[excalibur2]

I've always taken what is on the lens as a guide only, never worried if isn't accurate, it is usually close enough for a guessed distance, especially when you have to guess you would probably select a higher f stop anyway to be on the safe side

Yeah you're right, but interesting to know......was the reading on any prime lens ever accurate even when new. But have used the lens distance for hyperfocus a few times.

 

[MDJ]

The common recommendation used to be use a ground glass screen at the film gate. Problems with these include cutting to size to fit the film gate etc.

I have made an approximation of the ground glass using cut down pieces of CD Jewel cases and covering one side with frosted Scotch tape. Butt the edges neatly against each other. The tape side of this 'ground glass' should face the lens when placed in the film gate. Hold in place with rubber bands around the camera or even tape the plastic to the camera body to keep in place while you check the focussing.

 

[Cluster]

Thanks for your ideas. One small problem is that, with this being a super-duper camera, it has a curved film gate. The frosty looking document laminating sleeve didn't work well due it being a little too flexible. I have some thin acetate sheets and cut one of these to size, then gave one side a good sanding with fairly fine wet-n-dry. It worked well enough and gave me the sort of image that I hoped for. Job done now. If I ever get to grips with the modification of 120 film to suit a 127 camera, I'll be good for a trial.