For checking actual focus against the rangefinder....
For checking actual focus against the rangefinder....
The Scotch brand magic tape works, but I use a plastic Opague bowl, like tupperware with a largish side or bottom. I cut a piece the size of the film plane and put the frosted side against the film plane rails where the film rides. It works just like a real Ground Glass although that is also a very good way to go.
Then, with the camera open and the plastic or GG tapes to the back:
1) Set the camera on a tripod.
2) Mark off distinctly, 3 or 4 different distances.
3) Focus the camera via the GG method on the first distance (3-5 feet)
4) Check through the rangefinder to see if the patch shows focus.
5) Check the remaining distances the same way, say at 8-10 feet, 15 feet, 25 feet.
6) If the RF is off, there should be an adjustment cam, ie on the cam follower for the Fuji, riding on the lens just inside the mouth of the camera. Other camera's may have a hole for a small screwdriver for adjustment from outside, while on others the hood may have to come off to adjust a screw on a cam.
I adjust front cell focusing folding cameras also using this method. Using the same steps, and checking the front cell pointer/distance ring against the view method through the back of the camera.
There are usually three tiny screws on the distance ring on the front of a front cell focus lens. You loosen them just enough to turn the ring without turning the lens cell. Turn to right distance to the pointer, as the lens is focused. After you check and set the first midrange distance... say 10 or 15 feet, all the others should be on the money through the other measured distances.
I started out with the large flat from a tupperware bowl. I now have a good 6X9 ground glass that I tape, etched surface to the inside of the camera, to the back film plane of my Fuji's.
I've never actually had a Fuji that needed calibration, except one. I sent that one to Frank Marshman (Camera Wiz) for adjustment and some other work.
