Fokos Rangefinder - How do you operate them?

[mickjazz]

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A week ago I bought a black/nickel or maybe it's just brass Fokos in its original red Leica box.

 

Very pretty, not a scratch.  Bought it for a Leica ia I have.  It's missing the foot so it can't right now be horizontally mounted and swung out of the way as you see on Youtube videos etc. 

 

I thought it would be pretty straightforward to use.  A double image that closes when the large wheel is rotated.  but when I look through one of the apertures, it's just like a viewfinder window.  And I look through the other one, the view is more constrained.  But.., when rotating the dial the image merely shifts horizontally.  No double image.

 

What am I missing? Is it dysfunctional? Glass is spotless and view is very clear.  But there's nothing to focus.  Beam splitter gone maybe.  Does not look to have been opened. the very tiny screws look like new.

 

Ideas?

 

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[skucera]

I don't own a FOKOS, so I'm answering on the basis of owning six or seven rangefinder cameras.  The rangefinder has two sides.  The near side that you look into has one lens; the far side pointing at your subject has two lenses.  Look into that one lens on the near side, then turn the adjusting wheel until the two superimposed images of your subject coincide.  The pointer should point to the exact distance of the subject you focused on.  The next step is to set your lens to that indicated distance.

 

I hope your FOKOS works, and that you can find the mounting foot for it.  There's just something cool about using an uncoupled rangefinder on a Barnack camera.

 

Scott

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[mickjazz]

Thanks Scott. The Fokos must be different internally than the rf on the cameras. I was using it correctly but you kinda have to look for the patch particularly in direct light. Incidental illumination it's clearly visible. What I mean is that you have to rotate the vertical Fokos about it's axis to get the patch to show especially at very close objects within 1-2 m. But mine is extremely clear view. Thanks again for the suggestions. M

[luigi bertolotti]

Well, take into account that the reflected image (to say, the one that "moves" while rotating the distance dial) is significantly smaller than the image you see through the viewing lens... about 1/3-1/4  of the diameter, I'd say, so you must concentrate your sight on the central part of the view (which is natural, anyway) ... you ought to see clearly (in good light) a "central circle" with a slightly different appearance. 

[jc_braconi]

Hope this will help You understand how it works

 

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[willeica]

I have the FOKOS with the shoe; the combination is known as a HFOOK. Illustration below:

 

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You use the window beside the wheel for focussing. There should be a bright circle in the middle which should show two images, which will eventually co-incide when you turn the wheel. If you do not see the bright circle at first, moving your eye position should reveal it. It is slightly awkward for spectacles wearers such as myself, but you soon get used to it. If you do not see the two images in the bright circle there may be something wrong with the internal arrangement, which might not be too surprising in an item that is 80 to 90 years old. The FOKOS will work vertically in the camera shoe if you do not have the foot for the HFOOK arrangement. The images will move vertically to coincide rather than horizontally.

 

Now for some caveats. I have the FODIS/FODUA and the FOFER as well as the FOKOS/HFOOK. It is rare that one of these works perfectly. Not only are they old, but they are unlikely to have been subject to CLA/adjustment by a technician, unlike the rangefinder in a camera. One of my FODIS models has had the wheel/marking screw reversed and so it may have been worked on at some stage. I find that the readings from old rangefinders are 'approximately' correct at best. I generally use them just to confirm that I have the correct zone focus set. Shooting with one of my 1 Model As or Cs, I generally stop the lens down a bit to at least f6.3 and use zone focus. The rangefinder generally gives a good approximation of the zone focus.

 

The Standard illustrated above is a converted 1 Model A and the Elmar with no serial number has been converted from an 11 O'Clock infinity position to a 7 O'Clock position. If this had not been done then there would have been a danger of the user's fingers obscuring the right hand front window of the FOKOS which would cause the bright circle to disappear.

 

William

 

 

 

 

[luigi bertolotti]

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Fine drawing, JC !! Related specifically to FOFER, I think...

 

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[Pecole]

As I take all opportunities to look at my Fontenelle Collection archives, I looked for FOKOS/HFOOK when reading this thread. Here are the images I first found of both black and chrome FOKOS/HFOOK, and one mounted on a pre-war Leica Standard (similar to the Leica I as for telemeter mounting) and showing the pivoting. I also added images of the small yellow screen that may ease the viewing.

 

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[jc_braconi]

Fine drawing, JC !! Related specifically to FOFER, I think...

 

FOFER_my.jpg

The use is identical Luigi and not all the FOKOS have the pivot on the body to make it a HFOOK with the shoe

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[mickjazz]

Beautiful! These designs reflect the history of Leitz as a microscope and optical instruments manufacturer. I'd like to find the shoe for mine.

[willeica]

Beautiful! These designs reflect the history of Leitz as a microscope and optical instruments manufacturer. I'd like to find the shoe for mine.

 

If you look on ebay and elsewhere under HFOOK you may find one, although, most that are there include the finder as well and are, therefore, relatively expensive.  As in my own case, you can, occasionally, get the set with a camera. Where you see a FOKOS advertised it will most often not have the shoe which is much the rarer item.

 

William

[chris_livsey]

Interesting paper on the accuracy of these devices:

https://www.ludd.ltu.se/~torger/photography/leitz-fokos-review.html

[willeica]

Interesting paper on the accuracy of these devices:

https://www.ludd.ltu.se/~torger/photography/leitz-fokos-review.html

 

Thanks Chris. The findings here fit with my experience of using various different vintage rangefinders.

 

William

[DDM]

Dear JC,

 

you share my drawing...

Nice :-))

[Leicapasion]

How many variations of FOKOS exist?

[willeica]

How many variations of FOKOS exist?

 

Possibly 8. There would be black and nickel, black and chrome and all chrome in both meters and feet making 6 variants. The FOKOS was also sold as the HFOOK with the shoe and clip but it would still be the same rangefinder. There was a post war variant sold as chrome only with no mounting post, so that may add a seventh variant. Jim Lager also shows a shortened version for use with a left hand release.

 

William

[Leicapasion]

Possibly 8. There would be black and nickel, black and chrome and all chrome in both meters and feet making 6 variants. The FOKOS was also sold as the HFOOK with the shoe and clip but it would still be the same rangefinder. There was a post war variant sold as chrome only with no mounting post, so that may add a seventh variant. Jim Lager also shows a shortened version for use with a left hand release.

 

William

https://photos.google.com/search/_tra_/photo/AF1QipMhxzV9Y833STKJchADkUC35Bmkg2ubgg4HQqLU

A fast internet search. Any more?

[Pecole]

Possibly 8. There would be black and nickel, black and chrome and all chrome in both meters and feet making 6 variants. The FOKOS was also sold as the HFOOK with the shoe and clip but it would still be the same rangefinder. There was a post war variant sold as chrome only with no mounting post, so that may add a seventh variant. Jim Lager also shows a shortened version for use with a left hand release.

 

William

 

I had one of these chrome late FOKOS (scaled in meter), and even with its leather purse. Here is a photo.

 

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[ragarecords]

I recently obtained an older, log-base fokos, similar in appearance to that of the OP, but a bit longer. It is in need of lateral adjustment: when the wheel is at the infinity mark, objects about 75 feet away are coincident (fused) in the rangefinder. Judging by the damage to the screw in the middle of the wheel, I imagine that is the adjustment screw. Then there is the pin nut (?) around the screw.

 

Before I tackle it I'd appreciate any advice.

 

The patch is usable, but could be a lot brighter. Thanks to jc_braconi we have the cross-section; one can see that it is a semi-silvered mirror that does the job; I imagine not too much can be done short of replacing the mirror, probably beyond my pay grade.

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Hallo,

Look here: Interesting Leica gear

[jerzy]

Replacement mirrors are available and full repair is not costly, it takes 1-1,5 hours for repair including cleaning and adjusting. Drop me PM if you need more info