NewB questions about focusing differences between different lenses.

[BLeventhal]

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Hello and thanks to all who reply. 

I am a long time photographer who has flirted with Leica rangefinders in the past Leica CL in the 1990's and M8 in 2011. I have recently returned to the world of rangefinders with the purchase of a beautifully brassy M10 and 35mm f2 Summicron Asph. The pair are a perfect match and the rangefinder is precise and accurate enough for me to produce sharp images at f/2. 

I recently acquired a new to me lens to serve as a short telephoto. I purchased a Voigtlander 75mm f1.8 Helier Classic from MBP. I did not want a "perfect" optic, but something with a bit of character. Well this lens definitely has character, as the point of focus is never in focus, while the near background is sharp. Clearly, it appears that the lens is back-focusing. So here is my question... is it possible that the same camera rangefinder can focus one lens accurately while back-focusing a with a different lens?

I forgot that I can use live view, as I never use this feature, but I am going to see if I can produce a sharp image using the LCD and compare that with the rangefinder.

Bottom line,... if this is a lens issue, I'll return the lens and just be a one lens Leica shooter.

regards... bruce

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[Mute-on]

In short, yes it’s a lens issue. Leica lenses can be adjusted (shimmed, usually) to match tolerances more accurately with individual cameras. This would require sending the lens and camera to Leica for adjustment.

In you case it would be far cheaper and faster to return the lens and try to find another that is better matched to your particular camera  

 

[hansvons]

2 hours ago, BLeventhal said:

Bottom line,... if this is a lens issue, I'll return the lens and just be a one lens Leica shooter.

Hi Bruce,

If your M10 Summicron combo produces sharp images, your range finder is in working order. The chances are low that the range finder is off and the Summicron is also off, somewhat miraculously compensating each other.

I shoot 98% on 35mm (M6 plus the same Summicron as yours or for landscapes the 35mm Summarit and an M4P). Shooting with only one lens isn’t restrictive but liberating on many ways.

I‘d let go the Voigtlander 75mm and call it a day. May be, at some point, you might think of a portrait lens again. The 50mm Summicron V4 (got the focusing tab) in the Canada version is (relatively) budget-friendly and compliments the 35mm Summicron ASPH very well. Other than that, the Voigtlander 35mm Nokton f/1.4 in the SC version is a surprising Summilux V1 Steel Rim copy that renders almost undistinguishly like it’s role model from the 60ies l with tons of flare, glow and other "features". 
 

Hans

Edited July 11, 2024 by hansvons

[250swb]

1 hour ago, BLeventhal said:

 

I forgot that I can use live view, as I never use this feature, but I am going to see if I can produce a sharp image using the LCD and compare that with the rangefinder.

 

You should really have done that first to answer yes or no.

I doubt Leica would work on a Voigtlander lens but the worst thing to do is adjust a lens match a particular camera, and visa versa. The camera should be adjusted to it's tolerances and a lens should be adjust to it's own tolerances, then you have a lens and camera that can work together and each with other cameras and lenses. 

And your Voigtlander could be perfect and your M10 and 35mm combo are out of adjustment, maybe if the camera has been adjusted to match an out of tolerance lens. There is also the issue of focus shift which is a natural feature of some lenses (including Leica) which manifests itself visibly at wider apertures where it's really just a case of getting to know the characteristics of your lens, but I don't know if this Voigtlander suffers from it. 

 

[spydrxx]

In my experience most of the Voigtlander lenses I've owned focus spot on. My 75 (2.5 rather than your 1.8) focus just fine. I'd check live view and seriously consider finding a better copy of it if indeed it is out of whack.

[lct]

12 hours ago, BLeventhal said:

[...] I forgot that I can use live view, as I never use this feature, but I am going to see if I can produce a sharp image using the LCD and compare that with the rangefinder [...]

I have no experience with the CV 75/1.8 but my Nokton 75/1.5 is accurate on both my M11 and M240 in RF as well as LV mode so i would compare in LV mode if i were you. I would do it at working aperture to avoid focus shift effect, if any. Just as a precaution as i don't know if focus shift is an issue on the CV 75/1.8.

 

 

[BLeventhal]

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Thanks to all that replied. 

I continued testing the lens today and decided to return it to MPB. The lens does focus in LiveView, but back focuses significantly when I use the rangefinder. I test the lens at both "close" distances and full body portrait distances. I could not get the lens to focus accurately when relying on the rangefinder. To be clear, I compared similar shooting scenarios with my 35 f2, and the performed as it should. 

Thanks for helping me to understand that the lenses could be miscalibrated. This is a problem w/ DSLR's but there are times when it is body/lens combination that is the problem.

regards, bruce

[Bart D]

The Voigtländer 75mm f1.8 Heliar is known to have a focus shift issue.

That could be your problem rather than a miscalibration.
The focus shift wouldn't be affecting your live view.