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  1. #1

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    2/50Summicron DR goggles alignment

    I got a 2/50 Summicron DR with misaligned goggles. I found out that I can screw the cylindrical frame on the front loose a little and turn the prism from the back. This way I get pretty close in Adjustment but either the distance is right or there is a small deviation of about appr. 1 degree left. Is this normal or should the rangefinder spot be perfectly in match if the distance is right?

    Ulrich

  2. #2
    David Lyga's Avatar
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    Ulrich, my German is profoundly nonexistant. But semantics does, indeed, play a part in any lexicon, East or West. Confusion reigns here.

    'Goggles' presents the most formidable task: what do you really mean? Are you talking about eyeglasses, diopters, or what? I am terribly confused as to what this 'cylindrical frame' really is but I am, nevertheless, am intrigued to help you. The 'looseness' also flummoxes me. It does seem that you are fitting something onto the mount that is a degree off. I wonder if the rangefinder lever (which meets the rear of the lens to determine distance) is really being affected by such degree deviation. But I do not know. Maybe someone else who can 'read into this' will be better at such detection. I never was good at solving puzzles but I want so much to delve into this and present a responsible response. Please help me, more creative types.

    You know, Ulrich, my mental density just gave way to the possiblilty that you really are talking about 'goggles' and not a Leica RF camera. I know nothing about such optics but I wanted to advertise to all that sometimes there really is a light bulb in a thick head that has not, as of yet, burned out (albeit, remains dim)!!! - David Lyga

  3. #3

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    Hi David,

    my English comes to its limits here too. I own a special version of the 2/50 Summicron. It has two ranges. One normal from 1m to infinity and one from about 50cm to 90cm. For this "near macro" range the rangefinder has to be corrected with a special attachment which in German is called "Brille" or eye glasses or maybe goggles in English. Its shape indeed resembles to eye glasses, as it consists of prismatic lenses in front of the finder and the rangefinder window. One is rectangular in shape, the other is round and attached with a cylindrical ... I don't know, may be bracket is the right English term. In German it is "Fassung". If you screw loose this "bracket" a bit, you can turn the prismatic lens from the back. So far I have found out what to do.
    My problem is: If I look through the finder and adjust the taking lens to an object in say about 60cm distance, the scale will show 60cm. All is right so far except there is something what I now know as skew between an edge of the object and its rangefinder picture of about 1°. If I adjust the prismatic lens in front of the rangefinder window such that there is no skew. The scale of the lens shows the wrong distance.
    So all I need to know is whether this is ok or whether there should be a perfect alignment in the rangefinder patch, as it is case in normal operation between 1m and infinity.
    I hope I could make it more clear now. I usually need some time to get familiar with terms needed to talk about topics new to me.
    Last edited by Ulrich Drolshagen; 04-26-2013 at 05:55 PM. Click to view previous post history.

  4. #4
    David Lyga's Avatar
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    Ulrich, you taught me something. I did not know that there was a 'dual range' lens made by Leica. That is interesting. But to have a minimum distance of only 50 cm (or 20 inches in avoidupois) is not too impressive. A Takumar 'normal' focuses to less than one foot (about 30 cm). And it does that without having to switch to another mode. But, maybe there are reasons and justifications that I am unaware of. What you are referring to is this and is called a 'dual range Summicron': http://www.cameraquest.com/m50dr.htm

    Call the upper part 'eyes' (!) according to this article. They provide parallax correction and allowing close focusing. I am not familiar enough to properly answer your question, Ulrich, but we both know that the scale focus on your lens should be the prime determinant as to what is in focus. Obviously, if you are getting a different reading in the viewfinder, something is amiss. The 'eyes' are mountable ONLY when the lens is focused closely (there is a dovetail preventing it from being mounted at further distances). It would seem to me that at the point of being able to attach the 'eyes', either there is a misalignment possible or the optical correction in the 'eyes' is off by a little.

    This is probably the primary reason why I like SLRs more the RF cameras. What you see in the viewfinder is that which will actually manifest onto the film plane. Certainly, Leica is fully capable of matching the precision of any SLR, but ... the things that can go wrong in attaining this optimal situation are always threatening to downgrade this ability. To me, the actual optical 'readout' of an SLR is far more worthy of depending upon than the 'readout' provided by a lever (that could become inaccurate with time).

    Sorry that I could not have been of more help.

    PS: And if I may piggy-back onto your thread: Why is it that RF lenses do not focus as closely as those made for SLRs do? - David Lyga
    Last edited by David Lyga; 04-27-2013 at 09:40 AM. Click to view previous post history.

  5. #5

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    David, I suppose the nearer the distance the more optical challenging it becomes to correct the rangefinder. They gave up the concept in later times as it turned out not to be competitive to SLRs anyway, I suppose.
    I am a little bit further with my problem now. From what I've learned from cameraquest (the site you mentioned), I have the first version of the lens with the "eyes" from the second version. According to cameraquest, something that should not be possible mechanically. The only way to accomplish this is to "frankenstein" the eyes of the second version with the foot of the first version.
    As it seems, it is not possible to adjust the eyes correctly as there are about 8cm in range missing, that means: If I adjust the eyes such that the horizontal alignment is correct for the greatest distance the scale shows 58cm while focused on an object 50cm away and the scale shows 80cm when focused on an object 88cm away if adjusted from the short distance. In either case there is a vertical misalignment of about 1/3 of the height of rangefinderpatch.

  6. #6
    Richard Sintchak (rich815)'s Avatar
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    I have a DR with "eyes". I rarely use the eyes but as a set its more valuable I guess. That said the 50/2 DR Summicron is my favorite Leica lens. Wonderful sharpness with moderate contrast which is just what I look for in much of my B&W work. Incredible lens.
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  7. #7

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    Quote Originally Posted by Ulrich Drolshagen View Post
    Is this normal or should the rangefinder spot be perfectly in match if the distance is right?
    Mine matches perfectly, H & V, all distances. Whatever you do, don't throw out the lens. The eyes are mostly a collector's item in the modern SLR world, but the lens on its own never leaves my M--the only Leica lens I like almost as much as my Nikkors... It's very very good.

  8. #8

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    All right, I got it straight now. The Problem was, that you have to place an object in the exact distance of 88cm, the largest distance possible, to adjust the prism. The zero point of the scale is the back of the camera, not the front lens. It is all working properly now. Thanks for your interest.

  9. #9
    David Lyga's Avatar
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    Ulrich, I could almost guarantee that if the lens alignment is perfect BEYOND the 'macro' distance, then the problem HAS to be with the alignment of the 'eyes' themselves. I would use the lens withOUT the eyes and measure distances closer with a tape measure. - David Lyga

  10. #10
    fotch's Avatar
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    I never had the "eyes" for mine, never really needed them.
    Items for sale or trade at www.Camera35.com

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