Dual range Summicron with misaligned close focusing range

[Braaamer]

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maybe someone has experienced the same issue and knows how to fix it.

After having had a number of images out of focus when using the close focus range, I took the Summicron with goggles to a small test on my Leica M3:

Focusing scale set to minimum distance of 48 cm, matchbox place 48 cm from the film plane, range finder patch not lined up with the primary image in the viewfinder - image is in focus:

 

Matchbox still at a distance of 48 cm from the film plane, focus as per the rangefinder patch being aligned in the viewfinder, scale now showing a focus distance of 54.5 cm - image out of focus:

I repeated the setup with the matchbox sitting at 70 cm from the film plane. When setting the focus scale to 70 cm, the image is in focus despite the range finder patch not being aligned in the viewfinder. When focusing as per the rangefinder, this scale showed 84 cm, and the resulting image was out of focus.

Focusing per the scale is of course not very practical, I should be able to focus using the rangefinder as intended. 
 

is there a physical adjustment that can be done to the lens to fix this?

 

Best regards,

Erik
 

[spydrxx]

Yes, BUT, since you asked rather than already knew, I'd suggest having a trained technician perform the adjustment rather than trying it yourself, as it is rather tricky, and they have all the equipment to do it right without damaging the mechanisms.

[Braaamer]

Thank you, Spydrxx, I wouldn’t dare do it myself but have it done by a professional. Good to know that there is a separate adjustment for the close focus range. 

[TomB_tx]

DAG adjusted my close focus goggles perfectly when I had him CLA the lens.

[Braaamer]

Thank you, Tom, but I guess sitting here in Germany means that DAG is not really an option. But  will contact my CLA partner. 

[Huss]

On 3/12/2023 at 4:46 PM, TomB_tx said:

DAG adjusted my close focus goggles perfectly when I had him CLA the lens.

I need to send him mine.  Lens is great, but the goggles are way off.

[Infantasy]

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you can adjust the goggle yourself by rotating the round glass on the right if you dare to do so.

[Braaamer]

Thanks, Infantasy, that's interesting. I may want to give it a go - carefully. On the backside of the goggles, I see the dark ring holding the lens on the right in place. It has two notches that I assume I need to engage with a suitable tool and twist until the object distance measured with a tape, the lens focus scale and the rangefinder patch are all nicely aligned. 

If I rotate that dark ring in the goggles, will it move the lens back or forth? And how would that ring stay locked in its calibrated position after that rotation? Purely by friction? 

Thanks,

Erik

[Infantasy]

Don't loosen the dark ring from the back notches. It is hard to unscrew from that side and the dark ring should sit there without drifting. Since only the lense of item 10 was drifted, you may drop some lighter oil to unscrew item 9. After unscrew 9, process the followings:-

1. Detach 10 from 9.

2. Rotate 10 until your focus patch is correct. Made a mark "A" at the same direction on 10 and 17 by a tape.

3. With 7 fixed on 17, screw in 9 on 7 tightly and mark "A" on 9 with reference to the "A" on 17.

4. Unscrew 9 again and use double side tape to stick 10 on 9 referring to the same direction mark "A".

5. Screw in 9 tightly until the mark "A" on 9 and 17 are the same direction.

6. Try the focus patch and it should be correct. Apply a thin cement between 9 and 17. That it.

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[Braaamer]

Wow, thank you very much for that detailed explanation! 

I will need to read through it thoroughly a couple of times and then decide whether I am brave enough to perform that procedure. 🙂

Best regards,

Erik

[Braaamer]

I didn't face any issue unscrewing 9 (including 10), but I cannot detach optical component 10 from mount 9. But I could get the range finder patch to align horizontally very well with the main view finder image at a set distance of the object with matching setting on the lens focusing scale. Vertically, there is a misalignment.

Never mind, as a first band aid, and so not to destroy optical component 10 when trying to press it out of mount 9, I just rotated the whole assembly to the correct angle, marked that position with a light pencil, then filled the (very, very narrow) gap with a thin thread. Now I just need to find something to fix this into place. I have a screw locking varnish, or I could use clear nail varnish, or some light glue - only a tiny drop of whatever I choose, and I will be happy for suggestions. 

Cheers,

Erik

[Braaamer]

Just used a tiny drop of clear nail varnish that I applied on one spot using a needle. I will check my “calibration” again tomorrow, but I think I’m good to go. 

[Infantasy]

That's good. Enjoy!

[Braaamer]

Works like a charme and is hardly visible at all. Thanks again for all your very helpful advice.