FED-2 rangefinder OK, photos out of focus?!

[mat619]

Hi there,

need your help regarding a weird problem I'm experiencing with a FED-2:

Lately I shot a roll almost exclusively using wide open aperture, and to my surprise and disappointment absolutely all 36 photos are slightly out of focus. Not by far, just enough so the subject is slightly out of focus, while something immediately before it is perfectly in focus, as if I'd messed up the range finding a bit.

Confused by this, I suspected the range finder adjustment might have become a bit off - it did that once a few years before. So I slid the hot shoe rangefinder that I'm successfully using for my Kodak Retina folder onto my FED, went for a walk around the block, randomly focusing on objects in all distances and compared its readings with those on the lens after I measured the range using the FED's internal rangefinder - spot on. The next experiment involved focusing with a manual M42 lens on a SLR and comparing distance readings with the FED again... looks good as well.

So... does anyone have an idea what the heck might be going on with my FED-2? Because I don't, to be honest... has the coupling between the rangefinder mechanism and the lens somehow magically gone bad over night?
😕

Thank you very much in advance for your advice!

Kind regards,
Matt

 

[Mudman]

what lens are you using? Some lenses have focus shift wide open or at a distance; the russian 50mm Sonnar f1.5 clone is known for this.

 

[mat619]

what lens are you using? Some lenses have focus shift wide open or at a distance; the russian 50mm Sonnar f1.5 clone is known for this.

Thanks for the quick reply - my Industar 26M, the only lens I have for it.

 

[Mudman]

Hmm. Well you could be seeing focus shift, though that's less likely with a tessar clone. It's also possible that your rangefinder is ever so slightly out of wack and you're not noticing the difference when comparing the two. Honestly it's hard to tell without seeing the photos in question.

 

[mat619]

Hmm. Well you could be seeing focus shift, though that's less likely with a tessar clone. It's also possible that your rangefinder is ever so slightly out of wack and you're not noticing the difference when comparing the two. Honestly it's hard to tell without seeing the photos in question.

I can try to scan (with my limited equipment) one or two examples of them, if that helps - but unfortunately not right now, I'm not at home currently. Will get back to you as soon as I've got the scans! 🙂

 

[JHutchins]

I think the distance scale on your lens is not capable of giving you the sort of precision in measurement necessary to confirm what your prints are already telling you -- the rangefinder needs adjustment. Especially as, if I'm understanding you correctly, it used to focus properly but now does not. It's certainly not focus shift which is something that is an optical property of the lens and predictable and not something that comes and goes from time to time (although focus shift is aperture dependent -- it is a shift of the plane of sharp focus with aperture so that a lens that is in focus at 2.8 say becomes defocused at 8 -- so I guess it could appear if you systematically shoot at one aperture then start using another).

Rangefinders can be knocked out of adjustment, sounds like yours has.

 

[Ko.Fe.]

If RF is OK, but images are OOF it means lens out of aligment.
Use focusing target at 45 degree with scale or just ruler with scale under 45 degree to the lens to take picture at MFD and determine if it is front or back focusing.

 

[Sid836]

I think that one has to verify first the distance from the lens mount to the focal plane (film plane) and then start the rest of the rangefinder calibration process. It should be as close possible to 28.8mm. If it is not so, then the mount has to be shimmed to bring that distance as close possible if not exactly to 28.8mm.
Then one can start adjusting the range finder, starting with calibrating the cam for the close range and finishing with adjustment for infinity.

 

[Ranchu]

I would just adjust the rangefinder to match the lens and leave it at that.

 

[BernardL]

You did not perform the most important check:
When rangefinder says object is in focus (no split image), is the image sharp in the film plane , i.e., check with a ground glass and a loupe. When using the RF, the distance markings on the lens are a subsidiary information.

 

[mat619]

You did not perform the most important check:
When rangefinder says object is in focus (no split image), is the image sharp in the film plane , i.e., check with a ground glass and a loupe. When using the RF, the distance markings on the lens are a subsidiary information.

That's a very good idea, unfortunately I don't have a ground glass at hand. Will try to find one and perform this test.

Thanks for all your advice, guys!

 

[Spyderman]

You could also use this method of "cheap almost-collimator" http://rick_oleson.tripod.com/index-123.html

 

[JHutchins]

That's a very good idea, unfortunately I don't have a ground glass at hand. Will try to find one and perform this test.

Thanks for all your advice, guys!

Wax paper.

A bit of glass or plastic to keep it rigid helps. Paper side toward the lens.

 

[Spyderman]

or frost sticky tape.