FODIS rf adjustment

[OlleJ]

I got a FODIS rangefinder not so long ago. It works nicely, but is a little bit off. Any suggestions how to adjust it?
It looks like a setscrew in the centre, surrounded by a (possible) locknut. Is that correct?

As I intend to use with my Leica I(A), and not just look at it, I'd like it to be correct. 🙂

/Olle

 

[Livesteamer]

Unless you are very good at such things I would say it should be left for someone experienced. I've got one just like it and I would hesitate to open it. Check with DAG or Sherry Krauter or perhaps Essex camera. Good Luck. The Leica 1 can be lots of fun. Joe

 

[greyelm]

If it is like other similar rangefinders then it is a simple fix. I have done this myself

Place an object at the closest working distance of the rangefinder, look through the eyepiece and line up the images. Without moving the dial loosen the screw, now rotate until the distance number meets the meets the mark, tighten and recheck. Check at infinity and repeat adjustment if required. I hope this is clear.

 

[Coldkennels]

Bumping an old thread: I understand the principles of adjusting the FODIS/FOKOS/etc. to be accurate at infinity, but I have one with an extra problem: the "arm" that connects to the back of the dial does not move freely; I only realised something was wrong when I almost got it dialled in at infinity, only to notice the RF image wasn't moving at the other end any more. I took off the dial and found this:



Obviously, the top position is supposed to be its resting point, but if you push the cam follower all the way in, it just stays there. I'd assume a dying spring, but pulling it back forwards is VERY stiff, so I think there's some dried up grease on the pivot at the end.

Removing the end cap at the "pivot end" reveals this:



I have no idea what those four screws do. Someone's obviously been at one of them over the years going by the wear on the slot, but due to the rust, I don't want to hack at them willy-nilly if I can help it - especially as there's a chance some or all of them may be holding the prism in place on the other side.

Has anyone else been this far into a FOKOS/FODIS/FOFER before to give me any suggestions or advice?

 

[d_c]

There's a gentleman in Japan called Kuramochi Nobuyuki who trades on eBay as nobbysparrow, and who publishes a booklet called "How to Clean Old Leica Lenses and Accessories" which has some servicing information in it on the FODIS rangefinder. I believe he also sells replacement beam splitter mirrors for these old rangefinders.

Oh, and you have a PM

 

[Coldkennels]

Thanks, @d_c. Turns out all I had to do was loosen those screws; the one that looked like it had been damaged had been over-tightened, was rusted solid, and had trapped the pivot in place. It took some WD-40 to break through the rust to allow me to ease it off (and it snapped the head of one of my favourite Wera screwdrivers in the process), but the arm is moving freely now. And as I thought/hoped, the spring still has plenty of life in it.

Now just to get it calibrated properly!

Oh, and for anyone who finds this thread in the future: those screws also adjust the vertical and rotational positioning of the rangefinder. The end cap can be quite tight - you might need some rubber grips to get it to move. The other end (where the eyepiece is) hides a screw, but that only holds the prism at that end in place.

 

[Erik van Straten]

"There's a gentleman in Japan called Kuramochi Nobuyuki who trades on eBay as nobbysparrow, and who publishes a booklet called "How to Clean Old Leica Lenses and Accessories" which has some servicing information in it on the FODIS rangefinder. I believe he also sells replacement beam splitter mirrors for these old rangefinders."

The beam splitter replacements from Nobu work good, but not as good as the original silver/glass beam splitters from Leitz. They are plastic foil and have a strong yellow color. To put them correct in an old Leica or Fodis is however absolutely not easy. If you have no experience with repairing old Leicas don't do it yourself.

The books that Nobu has written are marvelous. They are a must when repairing an old Leica.

 

[Duofold RF]

Leica Leitz rangefinder FODUA adjustment

If the infinite horizontal alignment is off, loos the nut with two holes adjust the center slot screw, then tight the nut. If you disassemble the rangefinder pay attention to the size of the 4 screws, one of them is shorter should be in this location where the rangefinder arm is located. If...

www.rangefinderforum.com

 

[Coldkennels]

Thanks, @Duofold RF. After cleaning everything up (including removing dried-up old grease, relubricating, and rebuilding the unit), calibration was actually very easy; loosen the "two hole nut" with a spanner wrench, spin the dial slightly, and retighten. I didn't even have to touch the centre screw post-cleanup - whereas before I was twiddling that screw all over the place and retightening the outer nut was dragging the RF back out of alignment.

I'm now bang-on at infinity, vertical is perfect, and close focus (at 3.5ft) is bang on, too.

All in all, a big win.

 

[Duofold RF]

View attachment 4833169

I have no idea what those four screws do. Someone's obviously been at one of them over the years going by the wear on the slot, but due to the rust, I don't want to hack at them willy-nilly if I can help it - especially as there's a chance some or all of them may be holding the prism in place on the other side.

Has anyone else been this far into a FOKOS/FODIS/FOFER before to give me any suggestions or advice?

These set screws are used to adjust vertical alignment. If not out of alignment do not mess with them.

 

[Coldkennels]

These set screws are used to adjust vertical alignment. If not out of alignment do not mess with them.

They don't just adjust vertical alignment; in order to remove the prism/cam follower assembly and the pivot it sits on, you need to back them all right out. I didn't have to do that in the end, but that might be useful information for someone down the line.

I think they also have a certain rotational effect on the RF image, as the instructions I found said "loosening the upper two setscrews and tightening the bottom two will move the RF image upwards". It stands to reason that the one overtightened screw in the top right of the four was causing the diagonal movement I was seeing when trying to adjust the RF's alignment at infinity; now they're more reasonably set, the RF image only moves laterally when adjusted.