Focussing a 111f

[erl]

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I have noticed that my 111f focus system appears to have two variables when focussing!

First there is the obvious adjustment to focus the lens and therefore the VF. Second, I have noticed that the mirror adjustment lever surrounding the rewind knob to 'clarify' the viewed image in the LH window actually varies the clarity according to the motif range. It does not affect the focus, just the viewed image in the window.

ie. There are different optimal settings for this lever for far and near motifs, regardless of focus.

 

have I got that right? If so, focusing can become a two adjustment action each time, if you are pedantic about clear vision. It has taken me some months to realize this.

Edited December 9, 2013 by erl

[luigi bertolotti]

The lever around the rewind knob is for fine focusing of the RF image, and a correction for eyesight defects.

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[250swb]

If the image is fuzzy adjust the dioptre, there are no rules just so long as the rangefinder is clear enough to focus accurately.

 

Steve

[erl]

Thank you Luigi and Steve for your responses. I am still a bit confused.

 

I can set the dioptre lever to optimize clarity of vision at a distant motif, that's fine. But a close range motif is better at a different setting, independent of the lens focus cam.

[M9reno]

I can only guess that this is due to variation in the quality of your own eyesight across different distances, but you know better than anyone, erl.

[erl]

I will attempt to get a friend to try my camera. The problem is these 111f's are so darn hard to focus anyway, it's hard to be definitive about the RF and patch.

 

I will report back if I get anything interesting to relate.

[wizard]

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...The problem is these 111f's are so darn hard to focus anyway, it's hard to be definitive about the RF and patch.

 

Not if everything is up to factory standards. I had my late father's IIIf cleaned, and it is a joy to focus, better even than my IIIg. If yours is hard to focus, the little mirror inside the focusing mechanism may need to be cleaned or even resilvered.

 

Andy

[earleygallery]

I set my lllf so that medium distances appear clear through the rangefinder, according to my eyesight. I never touch the adjustment lever during use (unless it's been moved accidentally).

 

I actually find the lllf easier to focus than the M2, since the rangefinder image is magnified.

[luigi bertolotti]

Thank you Luigi and Steve for your responses. I am still a bit confused.

 

I can set the dioptre lever to optimize clarity of vision at a distant motif, that's fine. But a close range motif is better at a different setting, independent of the lens focus cam.

 

That's no strange, and indeed consistent with what is written in the manual (see the phrase I evidenced with red) : rangefinder in itself is like a small telescope... and, as any telescope, it must be focused (in fact, the small lever we are speaking of has the infinity symbol engraved at its end position) ; personally, at the times when I used my LTMs (IIIc and IIIf) I used the lever at an intermediate position, like James... considering that at infinity one has no much to care about focusing.

Anyway, as said in another post, the cleaness of the optical parts of the VF/RF is in comparision much more important for having good focus operation : personally (but thinking of MANY years ago... ) I hadn't problem with focusing with ease... even with f 1,5 50s like Summarit.

Remember that, for better contrast, many appreciated (and some still use) the OKARO/ORAKO filters

[robert_parker]

I'd agree with Luigi's and James's posts, in that having the rangefinder and in particular its windows professionally cleaned and the mirrors re-silvered if necessary makes a huge difference to ease of focussing.

 

I hadn't realised that until I tried a IIB which had had a CLA and when I got my apparently unused IIf (also known as :eek:The Devil's Camera ) both of which had clean windows and rangefinder.

 

As with both of the above posters I set the infinity lever to suit my eyesight at my normal working distance and this is generally near enough for normal purposes. It might be best practice to re-set this lever if you were in a mission critical situation but in practice, I've never seen this done.

 

By the way, Kudos to you (if they sell any down the Greek restaurant ) for noticing that the focus drifts over the operating range, 'cos not many people know that...

[luigi bertolotti]

...

 

By the way, Kudos to you (if they sell any down the Greek restaurant ) for noticing that the focus drifts over the operating range, 'cos not many people know that...

 

True... and when one considers that can also mount the NOOKY....

[erl]

Aha! Robert you have pinned my suspicions that a 'drift' does in fact occur. Now I feel better as previously, I thought the 'drift' might be my eyes.

 

Since I don't really know what is the optimum to expect from he RF system, I may take wizard's advice and have my techy look at it wrt cleaning etc.

 

Thanks all for your invaluable input.

[payasam]

You may need to have the half-silvered R/F mirror replaced.

[250swb]

 

I can set the dioptre lever to optimize clarity of vision at a distant motif, that's fine. But a close range motif is better at a different setting, independent of the lens focus cam.

 

No that is correct, as the focus changes so you need to adjust the dioptre. It is in one place for infinity, and another for close ups, it is not about your eyesight as with the normal (or the more modern) meaning of dioptre correction. There is no set point to put it at for your eyesight, if the image looks fuzzy, you adjust the dioptre, otherwise you simply aren't getting the full-on sharp view of the rangefinder patch or the scene.

 

And this is a problem that comes up often with Barnack Leica's that haven't been serviced properly, or ever. The dioptre is now thought of as an adjustment for individual eyesight so it's function is overlooked if people can more or less see the image in the viewfinder. But have a well serviced dioptre and it changes the whole look through the admittedly still pokey little viewfinder window..

 

Steve

Edited December 11, 2013 by 250swb

[erl]

Thanks Steve. That explanation completely clears my query. I now only need to consider if my particular example is fully up to snuff.