M-Hexanon 50mm f2 back focusing on M8

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nandemofoto

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My new M-Hexanon 50mm f2 is back fousing on m8.
I read somewhere that in order to fix it I have to remove one of 2 shim rings in it.
Has anyone done that? How do I get to these shims?
Cheers!
 
nandemofoto said:
My new M-Hexanon 50mm f2 is back fousing on m8.
I read somewhere that in order to fix it I have to remove one of 2 shim rings in it.
Has anyone done that? How do I get to these shims?
Cheers!
Click to expand...

I'm just going from memory here, but IIRC the only thing I remember in reference to Konica regarding removing 2 shims was in reference to shims behind the lens mount flange of the Hexar RF camera body if there was a problem focusing Leica lenses with them. (My Hexar RF never needed that to be done, it was a tolerance thing).
 
Maybe you're thinking of only Leica's film bodies?

I've tried 2 M-Hex 50/2's on my M8. Both backfocused, one very badly and the other moderately so. UC-Hex 35, fine. M-Hex 35, fine. M-Hex 28, fine. M-Hex 90, fine.

Sean Reid has reported M8 focus issues with the M-Hex 28.
 
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According to this person on the auspiciousdragon.net you need to remove a shim from a lens.
"There are two shims in the Hexanon 50/2. They can be accessed easily by removing the mount. Removing just one made mine focus perfectly on the M8.

It is an amazingly good lens.

Kevin"

The question is how do I remove the mount. It's not just unscrewing the screws I have tried that...
 
i wonder whether removing the shim will cause the lens to misfocus on film cameras while focusing well on the M8.

i'm sorry i can't answer the question how to remove the mount.
 
It is very easy to remove the mount for M-Hexanons, so are Canon L mount lenses.
They have several ring shim with varying thickness of thin brass, My M-Hexanon 50/1.2
has five or six. Once you take out the mount by unscrewing 6 screws you can see
thin rings. Take one and shoot, then check the focus("pinnto" in japanese) in LCD on M8,
more precisely on your screen 100% enlargement is better. M8 is a nice tool. 😀

M8 ga areba nandemo dekiru.

PS. This method of changing shims is recommended only one or two lenses you own
have focus problem, otherwise you should change M8's focusing roller position using
small L type hex key. And find out the best compromising position, then fixing each
lens by changing number of shims. Oh, when you need more shims you have to find
some metal ring (does not have to be complete circular, 250 degree circle is enough)
which should be non rusty metal such as iron. Find copper or brass, or break unused
old camera(s), which I did. 😀
 
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1) The lens should be already shimmed/collimated for the M/HRF registration distance. Chances are your M8 is off, the lens is OK, and by changing the lens you make it unusable on any other Leica.

2) if the lens is indeed mis-collimated and back-focusing, i.e. focusing behind the subject, you need to make it longer, i.e. add, not remove shims. The shim thickness can be calculated from the back-focus you observe, at a given focus distance. What were those numbers, BTW. ?

I recommend professional assistance. Send Don/Sherry/etc both camera and lens.

Roland.
 
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ferider said:
...

2) if the lens is indeed mis-collimated and back-focusing, i.e. focusing behind the subject, you need to make it longer, i.e. add, not remove shims. The shim thickness can be calculated from the back-focus you observe, at a given focus distance. What were those numbers, BTW. ?

I recommend professional assistance. Send Don/Sherry/etc both camera and lens.

Roland.
Click to expand...

+1

Very strange, never heard or suffered this myself. Not with any M-Hex lens I own, used on M3, M5 and M8.

Almost sounds like you bought the lens from the guy on the other forum, who 'corrected' it!?
 
Thank you for your input everyone.

I don't think this is a problem with m8 since I don't have this problem with canon 50mm f1.2 nor summicron 35mm f2.

Koji,
unscrewing the 6 screws only allows me to take the mount off and doesn't give me access to any removable parts.
Are the shims directly under the mount?
 
roland, i may be blissfully ignorant, but i've only seen this problem on the m-hex 50/2. two of them, one from matsuiyastore and one from a member, neither seller claimed correction (both accepted a return w/o any issue). not so on the other hex lenses i've owned and not on any of the leica or zeiss lenses i've used on the M8. it doesn't seem to be a camera problem.
 
My recently acquired M-Hex 50/2 focuses properly on my M3. The previous owner said it focused correctly on his M6. Not sure why there would be any difference on the digital body. I suppose it could be sample variation, but this seems unlikely on a lens that is so incredibly well made.

Good luck with the adjustment. If you can get it right you will be very happy. I am blown away by the sharpness and contrast this lens exhibits.
 
Hm ... I have the same lens, 50/2.0 M-Hexanon and it focuses very exactly. I will borrow you my lens (ahem.... Steven has it borrowed from me) and then compare both lenses using your M8.
 
Here is a process to access shims in M-Hexanon 50/1.2,
I am not sure Pbase will work for this, if not visit this page>
http://www.pbase.com/kkawakami/inbox

large

large

large
 
Of course "left" counter clock wise, you can loosen by finger nail if you are lucky.
The other ring which contacts to camera's roller has only one position to fit in, also
the mount base too. So do not worry about re-assembling, only one way back. 🙂

Use a professional grade screw driver (philips type +) in order not to damage
6 screws. You can get it spanner too at TOKYU HANDS, a bit pricey thou.
 
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