Elmarit 2.8/135mm; goggle adjustment

[costakarl]

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Hi all,

 

Have followed a procedure to adjust the rangefinder image, working on the round goggle-eye.

 

I would now like to shift the whole image so that it coincides with what I see when a much newer 135mm is mounted on the camera, which is a recent MP.

 

I suppose this involves the rectangular goggle-eye, but the embedded screws are smaller still at 0.5 and I am reluctant to push my luck.

 

Has anybody tried this adjustment?

 

Karl

[luigi bertolotti]

Sorry, but I don't understand well which issue does your Tele Elmarit suffer; basically, the two "eyes" are simply a couple of enlargment lenses with the same power : the rectangular one enlarges 1,4x the finder image, thus making the 90 mm frame to effectively encompass the taking field of 135mm, and the round lens enlarges the rangefinder' small window image of the same 1,4x ratio, so that its projected image has the same size of the main (full size) viewfinder image, to allow RF alignement while focusing. There is a bit of tolerancing in the axial positioning of the goggle unit ("axial" referred to lens' axis), to say, it can be "rotated" some fraction of degree in respect to the nominal position : this can be due to bayonet mount tolerancing, and practically does not affect RF/VF for the two lenses of the goggle act the same way as above, So, my idea is that if you suffer some problem, it's not due to the goggle's lenses in themselves :

1) If the 135 mm frame looks shifted vs. the effective taking field, is a problem of the 90mm frame in the RF/VF unit

2) If the projected RF small window looks misaligned to the central part of the viewfinder window, is a problem of the rangefinder unit mechanics

3) If the focusing is uncorrect (not coincidence at infinity, or other focusing issue) that's a matter of rangefinder adjustement OR/AND Tele Elmarit's RF cam adjustement (generally speaking, but this is a delicate question, if the rangefinder is perfect with other lenses, the problem is in the 135's RF cam, that has its own adjustement system, that is better not to be operated do-it-yourself)

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[costakarl]

Thanks for the thoughtful reply.

 

To put it another way, the Elmarit 135 when mounted is not returning the same field as my Tele-Elmar-M. The rangefinder is working perfectly, so I suspect the goggle-eyes have received a knock. I was able to adjust the round goggle which magnifies the coincident RF images. (see: How to align goggles on 135 Elmarit M v1? - Photo.net Leica and Rangefinders Forum response Alan Wilder June 17th 2007) but I would like to know what adjustments can be made on the rectangular eye. There appear to be 8 screws around this viewer.

 

Of course the ultimate test would be to take comparative photos, but lacking a digital Leica this will take time.

 

karl

[luigi bertolotti]

Thanks for the thoughtful reply.

 

To put it another way, the Elmarit 135 when mounted is not returning the same field as my Tele-Elmar-M. The rangefinder is working perfectly, so I suspect the goggle-eyes have received a knock. I was able to adjust the round goggle which magnifies the coincident RF images. (see: How to align goggles on 135 Elmarit M v1? - Photo.net Leica and Rangefinders Forum response Alan Wilder June 17th 2007) but I would like to know what adjustments can be made on the rectangular eye. There appear to be 8 screws around this viewer.

 

Of course the ultimate test would be to take comparative photos, but lacking a digital Leica this will take time.

 

karl

 

You mean, I suppose, that the frame lines you see in the viewfinder with the goggled Elmarit mounted, cover a different field from the one framed by the Tele Elmar 135 (ungoggled, which activates another frame, the "real" 135 and not the "90 enlarged").

I can make some hipotesis :

1) If the field width is different in width/height from the Tele Elmar's one, the rectangular lens could indeed be someway mis-assembled... mounted uncorrectly so that its "nominal" magnification results wrong... I suppose that in this case you should notice also a certain blurriness/unsharpness in the whole rangefinder image (I noticed this into a Elmarit 135 I had in my hands time ago)

2) Or, the lens had been very badly serviced... got broke and was substituted by a not original one with uncorrect magnification (which, sorry, is 1,5x and not 1,4 as I wrote above... )

3) But if the field has the correct width and is simply misaligned in respect to the "real" 135 frame I'd say that the rectangular lens is not to blame... is a problem of the RF's framelines... 90 and 135 are not correctly centered (the frames are finely engraved onto a thin support... is a delicate component... in this case the issue ought to be noticeable also without the goggled lens

4) It comes to my mind that you say you have a MP : which kind of viewfinder do you have ? The 0,72x or the 0,85x ? Maybe there is NOT a real problem...

[costakarl]

You have correctly restated the issue. Also the MP has the 0.85x rangefinder, but I do not think this enters into the puzzle.

 

Experimenting further I used the goggle lens on both an M2 and the MP. The 90 frame is being employed. The width of the object field of a distant subject is the same for both cameras.

 

When I point the Tele-Elmarit 135 as mounted on the MP at the same subject the object field is noticeably wider. Of course the 135 frame is now being employed.

 

So I think you are right in inferring that the problem comes from the rangefinder construction and not the goggles. The next step will be to take some real pictures.

[Xmas]

Hi

 

The frame selector lever in both cameras should be in the same position.

 

Noel

[luigi bertolotti]

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...

 

So I think you are right in inferring that the problem comes from the rangefinder construction and not the goggles. The next step will be to take some real pictures.

 

A side observation... Leica states that at infinity the MP frames show an area that is 9% (28mm, not present in the 0,85x) to 23% (135 mm) LARGER than the effective area taken on the film... this is obviously to avoid errors at short distances (I do not remember well, but I seem the frame is correct at 1 or 2 meters), but it means also that (very probably) the 90mm frame is something less than 20% larger at infinity (with patience, one could infere the math they used) , so that when it is enlarged by the goggle's lens it is anyway smaller than the 135.

 

The 135 frame has always been someway critical... the external viewfinders made in the '30s (VISOR and similar) even had TWO frames for 135... one for infinity, a smaller one for minimum distance (1,5 mtr.)

Edited September 9, 2010 by luigi bertolotti

[ryee3]

I have had a similar problem with mine in the past. Leica in NJ fixed the problem.