Viewfinder Patch Question

[Pixeleater]

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Using an M10R, when I have focus dialed to infinity the object in the viewfinder patch is double vision. When I move the patch off the object it is no longer double vision. Any ideas as to why is this happening and what can I do to correct it? This happens when using the 35 Summicron, 50 APO and 50 Summilux.

Thanks.

Edited March 22, 2021 by Pixeleater

[Guest]

Make sure the object you are focusing on is at the correct distance to be considered infinity. If it is, then you will need to have your camera calibrated. 
 

On a 50, infinity is roughly 1500 feet. 

Edited March 22, 2021 by Guest

[jaapv]

3 hours ago, Pixeleater said:

Using an M10R, when I have focus dialed to infinity the object in the viewfinder patch is double vision. When I move the patch off the object it is no longer double vision. Any ideas as to why is this happening and what can I do to correct it? This happens when using the 35 Summicron, 50 APO and 50 Summilux.

Thanks.

It sometimes happens. Some lenses, especially third-party ones will focus slightly beyond infinity.  Take a few test shots to see whether the shots you take with the camera focused to infinity are sharper than the ones with the lens turned all the way. If the "lens" shots are sharper your camera or lens -or both- need calibration. Ideally you need an optical bench to calibrate properly, although it can be done using Live View - many Leica specialists can do the job for you.

A simple tweaking of the camera infinity setting is an easy DIY job.

Infinity is quite a bit further than 1500 feet for the rangefinder, irrespective of focal length. I find I can focus-differentiate up to at least 1 km. Whether the lens can render the small difference is another matter.

[Guest]

I suppose clarification would help. Using a 50mm anything under 1500ft at infinity (hard stop on the lens) is not in focus, anything beyond 1500ft (such as the moon, is coinciding in the RF). This was the result of my testing as I was trying to figure out if my RF was calibrated. 
 

Infinity is different for every focal length. As the rule of thumb you can add a zero to your focal distance in mm and read it as meters.

Edited March 23, 2021 by Guest

[Pixeleater]

21 minutes ago, Wallflower said:

I suppose clarification would help. Using a 50mm anything under 1500ft at infinity (hard stop on the lens) is not in focus, anything beyond 1500ft (such as the moon, is coinciding in the RF). This was the result of my testing as I was trying to figure out if my RF was calibrated. 
 

 

On my lenses infinity is a hard stop with no play beyond. I did not know about the 50 mm/1500 ft metric. The 50 APO jump from 15 ft - infinity and the 50 lux jump from 25 ft - infinity leaves very little room to adjust before 1500 ft let alone infinity. Is there a similar infinity metric for 28 and 35 mm?

How does this affect the issue with the focus patch double vision?

[Guest]

13 minutes ago, Pixeleater said:

On my lenses infinity is a hard stop with no play beyond. I did not know about the 50 mm/1500 ft metric. The 50 APO jump from 15 ft - infinity and the 50 lux jump from 25 ft - infinity leaves very little room to adjust before 1500 ft let alone infinity. Is there a similar infinity metric for 28 and 35 mm?

How does this affect the issue with the focus patch double vision?

Go outside and focus on the moon. The image should superimpose/coincide in the RF regardless of the focal length. 

[jaapv]

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6 hours ago, Pixeleater said:

I did not know about the 50 mm/1500 ft metric

Nor I. This value is for SLRs, not rangefinder cameras. A rangefinder does not focus through the lens, so the accuracy is independent of focal length. The focal length only gets into play when you correlate the rangefinder accuracy to the resulting image and DOF of a specific lens.

A rangefinder camera is always adjusted using a standard calibrated lens of known accuracy. Nowadays one can use the Live View for the purpose, it must coincide with the rangefinder. 
For the record: on my M9 most lenses are correct for infinity, but my Voigtländer Color-Heliar 75 has a distinct double image at infinity at the hard stop, so it clearly focuses beyond. No matter, in use the focus is always spot-on.

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In your case I would take the camera and lenses to a trusted Leica repair shop to have the whole system calibrated.