35/2 Biogon not focusing to infinity on M6, but OK on M9

[mervin106]

hello,

I recently purchased a Zeiss 35/2 biogon which seems to be perfoming differently on my 2 bodies(M6 & M9). On the M9, it seems to be focusing to infinity, but not on the M6. The images in the rangefinder patch are not aligning. Has anyone seen this before?

Many thanks.

 

[elmer3.5]

Hi, i had the same outfit m6 + bigon 35/2, no problem at all.
Try checking with other lenses if persist perhaps the RF is out of alignment!

Luck!

 

[efix]

hello,

I recently purchased a Zeiss 35/2 biogon which seems to be perfoming differently on my 2 bodies(M6 & M9). On the M9, it seems to be focusing to infinity, but not on the M6. The images in the rangefinder patch are not aligning. Has anyone seen this before?

Many thanks.

On my M8, the Biogon won't focus to infinity. A Zeiss guy told me this was due to the slightly different flange distance on an M8 compared to film M's, so the lens has to be adjusted for digital. Maybe you've got such a version, and that's why it doesn't work correctly on your M6? Just a guess, though.

 

[250swb]

On my M8, the Biogon won't focus to infinity. A Zeiss guy told me this was due to the slightly different flange distance on an M8 compared to film M's, so the lens has to be adjusted for digital. Maybe you've got such a version, and that's why it doesn't work correctly on your M6? Just a guess, though.

This would sort of imply that all Leica lenses made before the introduction of the M8 would need adjusting as well, which of course they don't. And it would mean all Leica lenses built after the M8, and supposing they are optimised for digital, would need adjusting to work on film bodies, which of course they don't.


Steve

 

[reuno]

Are other lenses ok on the M6 ? Maybe this is the camera that needs adjustments...

 

[mervin106]

Are other lenses ok on the M6 ? Maybe this is the camera that needs adjustments...

I have a 35/2.5 Skopar and a 50/1.1 Nokton that focuses ok on the M6. I've yet to try other lenses. I'll take it to a repair shop and see what they say.

 

[elmer3.5]

M8?

M8?

Hi, on my M8 the bio 35/2 gets perfect infinity!

Bye!

 

[Bill Blackwell]

On my M8, the Biogon won't focus to infinity. ... due to the slightly different flange distance on an M8 compared to film M's, so the lens has to be adjusted for digital. ...

This would sort of imply that all Leica lenses made before the introduction of the M8 would need adjusting as well, which of course they don't. ...

Precisely!

Some lenses do indeed need to be adjusted, but not because there are any differences in the distance between the lens flange and the film plane.

The fact is, the digital sensor is completely flat - film is not. This makes the accuracy of lenses critical when using the digital body. About half of my Leica lenses had to be adjusted when I started using the M8. There was nothing ‘wrong’ with my lenses; tolerances are simply 'looser' with film cameras.

 

[mervin106]

Just got back from my local Leica service shop, they tested both the M6 and Biogon 35/2. The rangefinder on the M6 is ok. Turns out the tolerance on the 35/2 has to be adjusted. I'm now deliberating if I should send it back to Zeiss or just live with it. Since the photos are not affected when focusing at infinity.

 

[Roger Hicks]

On my M8, the Biogon won't focus to infinity. A Zeiss guy told me this was due to the slightly different flange distance on an M8 compared to film M's, so the lens has to be adjusted for digital. Maybe you've got such a version, and that's why it doesn't work correctly on your M6? Just a guess, though.

Who on earth was this 'Zeiss guy'? Because he hadn't the faintest idea what he was talking about. WHY would Leica do this? And how come so many of us have no probems at all in using lenses interchangeably on film and digi?

Cheers,

R.

 

[Bill Blackwell]

Just got back from my local Leica service shop, they tested both the M6 and Biogon 35/2. The rangefinder on the M6 is ok. Turns out the tolerance on the 35/2 has to be adjusted. I'm now deliberating if I should send it back to Zeiss or just live with it. Since the photos are not affected when focusing at infinity.

The tolerances will be most apparent when close focusing (as demonstrated by front or back focusing). Personally, I would have the lens adjusted - it is not that expensive, you only have to do it once, and your shots will then be reliable throughout the range intended for the lens.

This 'tolerance' issue is common not only to Zeiss lenses.

 

[efix]

Who on earth was this 'Zeiss guy'? Because he hadn't the faintest idea what he was talking about. WHY would Leica do this? And how come so many of us have no probems at all in using lenses interchangeably on film and digi?

Cheers,

R.

Someone from their CS. Possible he got it wrong 🙂

 

[Avotius]

If you adjust the lens for the M6 it will have difficulties on the M8 wont it? I say live with it, if you want infinity, stop down a hair, if the lens is fine everywhere else then its probably ok.

 

[mervin106]

If you adjust the lens for the M6 it will have difficulties on the M8 wont it? I say live with it, if you want infinity, stop down a hair, if the lens is fine everywhere else then its probably ok.

That's the thing, I do not know what is involved with adjusting the tolerance of a lens. 🙄 I'm guessing if I send the lens back to Zeiss, they would also need my M6 to properly calibrate the body and lens. But could mess up the focusing on my M9 🙁

 

[Avotius]

I think what they will do is either shim the lens or put on a different mount with a different tolerance. I saw something before about if your camera is (in grossly basic tolerance terms) a +5 and your lens is a +5 then you are +10 and way off. The ideal thing is everything at zero (very difficult) or have a +5 body and a -5 lens.

 

[furcafe]

Since you write that you haven't experienced any real world problems w/the Biogon on your M6 (& I'm guessing also no problems w/the M9?), I wouldn't worry too much. If you notice significant (to you) focusing problems w/the M9, then I would have the lens adjusted for that body. As BillBlackwell noted, the M9 is the higher tolerance body, so IMHO, making sure it works properly w/that body would be the higher priority.

That's the thing, I do not know what is involved with adjusting the tolerance of a lens. 🙄 I'm guessing if I send the lens back to Zeiss, they would also need my M6 to properly calibrate the body and lens. But could mess up the focusing on my M9 🙁

 

[mervin106]

Since you write that you haven't experienced any real world problems w/the Biogon on your M6 (& I'm guessing also no problems w/the M9?), I wouldn't worry too much. If you notice significant (to you) focusing problems w/the M9, then I would have the lens adjusted for that body. As BillBlackwell noted, the M9 is the higher tolerance body, so IMHO, making sure it works properly w/that body would be the higher priority.

Yes, that is correct. No issues with photos, that I can see.

Thanks everyone for your comments!