Discount Voucher for Leica M

[scott kirkpatrick]

Re: Leica M Aesthetics

What linkage are you referring to that would affect the "sharpie-code non-Leica" lenses?
...
G

When you take an M8 apart, you find there are two microswitches that pass two leading bits of information to the firmware processor, making the lens's 6-bit code into an 8-bit code. The 8-bit part was confirmed by finding the tables in the firmware which contained the information which is patched together into the EXIF. So there are four possible states, only three of them needed. There are several linkages connecting the microswitches to both the frame lever and to the lug on the mount which determines whether the lens is a 35, 50 or 90. If you have a thread mount lens in a bayonet adapter, e.g. for old Canon lenses or early Voightlaender lenses -- then the lug determines what sort of lens you are supposed to be. Sometimes you have the wrong adapter or (if you are Zeiss) just chose the wrong lug position. Then in the M8 and M9 you could override the lug position with the frame lever, but it only worked in one direction -- I believe the frame lever correction was sensed in the 90 direction, but not felt in the 35 direction. The reason was the linkages, which had to sometimes tug and sometimes slip to make all this work. Since the firmware turns off corrections which aren't recognized on all 8 bits, this gives a way to override vignetting and color shading corrections which are too strong in some circumstances... And it is the explanation why some sharpie codes don't work.

But did you really want to know all that? There are nice pictures of this in this article. Go to post #9 for the linkage and description of how the mount lug is sensed. The pictures don't show how the frame lever input is added -- that was found out by trial and error.

scott

 

[algrove]

Leica is now making official the price some dealers have been charging for new cameras for some months now.

 

[Godfrey]

Re: Leica M Aesthetics

Very interesting, thanks scott. Hmm, I can't see any pictures on the L Camera Forum unless I become a member. Gotta think about that.

I've sort of stopped using the six-bit lens code reader now. I mostly use three lenses with the M9 and I set up user configs for each of them, so when I swap lenses I just switch the config to the one that has all the base settings and lens code that I want the camera to use.

G