SL66 Focus Screen seems to be out

[Wishy]

Hi,

Have got myself a "new to me" SL66, which was sold as serviced. Mechanically it seems to be all good (Shutter is light tight, speeds seem "about right", film spacing is good), but when I shot my test roll i found the focus seemed to be out. It was a dull evening, so it could have been me, but also when I focus on infinity, the focus distance on the side shows between 6 and 10 meters, and you definitely have to push the bellows out a bit to get in focus.
The frame on the focus screen also seems to be slightly bent.

So I guess my question is, I presume infinity should match up with the back focusing stop, and does anybody know where spare parts can be obtained?

Cheers

Steve

 

[Dan Henderson]

I don't know the SL66 model, but if the the frame on the focus screen is bent as you say, I would be very suspicious. Try this experiment: set up a measuring stick at a 45 degree angle away from the camera, focus on a number in the middle of the stick, shoot a frame or two with the lens wide open, develop the film and see if the same number is in sharpest focus on the negative.

 

[Wishy]

Thanks dan, That sounds a sensible step.

Heres a picture of the focus screen - http://www.wishy.co.uk/SL66-Focus.jpg - looks to me like that would be enough to cause problems.

 

[Ulrich Drolshagen]

Probably the groundglass is mounted upside down. It must be mounted with the fresnel-side to the mirror. It is easy to fix.

Ulrich

 

[Wishy]

Well I never expected that. I've just flipped it and infinity seems to match up now. Does seem to be the wrong way round compared to the rest of my cameras

 

[Dan Henderson]

I would still worry about the "warped" frame, unless the finder fits down tightly on it and holds it flat. Barry Thornton, who wrote a couple of books on sharpness, used an SL66 and I seem to recall him writing in one book that even a grain of sand underneath the ground glass would be enough to throw the focus off.

 

[Wishy]

Yes, i did a test roll last night and its significantly better, but I'm not sure its perfect.

I've spoken to Jurgen (SL66 repair man) who has a replacement he can sell me, so I'll spend the money to get it right. No point having a 500 quid camera, top quality glass and get poor results for the same of a 50 quid part.