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ZM flange issue!

sisoje

New member
Hi,
I have a question:

I recently bought a used Zeiss ZM 21/2.8 lens. It brings up 28mm frames when mounted on M9. Now, I have a few "old" Zeiss ZM flanges from last time I had ZM lenses (and M8). One of those flanges ALSO brings up 28mm frames BUT has totally different position of holes (yes, on this flange one of the holes is right where one of the 6bits should be!)...

Back to flange that is on my 21mm lens: as I said, this flange brings up 28 frames and the design of it is bit different. It has a recessed surface, so the previous owner did mark it with sharpie for a 6bit read but a wrong (28mm) lens. I am currently using this lens on my M9s with no problems.

I would love to send the old flange to JLM for coding (before taking off the flange on the lens). I am puzzled on how it can be TWO DIFFERENT ZM FLANGES FOR THE SAME 28mm FRAME LINES?

Any input would be great!
Thanks.
 

250swb

Member
I have the 'new' version of this lens with the recess for coding in the flange and it works fine with my M9.

As I understand it the 'old' flange had a screw hole in a position that coincided with one of the screw holes on a Leica's bayonet ring. This could cause a small light leak that shows up as flare on the film or sensor, hence a modified flange so Zeiss could avoid user grief.

Steve
 

jlm

Workshop Member
Jlm here
We can add the recesses to the new style even with the relief and new hole pattern
 

Godfrey

Well-known member
Hi,
I have a question:

I recently bought a used Zeiss ZM 21/2.8 lens. It brings up 28mm frames when mounted on M9. Now, I have a few "old" Zeiss ZM flanges from last time I had ZM lenses (and M8). One of those flanges ALSO brings up 28mm frames BUT has totally different position of holes (yes, on this flange one of the holes is right where one of the 6bits should be!)...

Back to flange that is on my 21mm lens: as I said, this flange brings up 28 frames and the design of it is bit different. It has a recessed surface, so the previous owner did mark it with sharpie for a 6bit read but a wrong (28mm) lens. I am currently using this lens on my M9s with no problems.

I would love to send the old flange to JLM for coding (before taking off the flange on the lens). I am puzzled on how it can be TWO DIFFERENT ZM FLANGES FOR THE SAME 28mm FRAME LINES?

Any input would be great!
Thanks.
The previous responses addressed the lens type coding but missed the question about the frame lines.

The frame line mechanism is mechanical and is based on the slope of one of the bayonet flange edges pressing a lever when the lens is fitted. The lens id system for EXIF data and lens correction is entirely independent of that frameline selector mechanism.

So two different flange designs at the mount interface for the lens id coding has nothing to do with the fact that the two 28mm lens flanges have the correct shape on the frame line selector bit.

G
 

sisoje

New member
Thanks for all replies!
My question now is: can I mount "old style" flange (with hole where the bit suppose to be) on the updated lens (that I have)?
My intention is to send the "old" flange to John for coding and once I get it back just replace it on my lens. The issue is that holes on two versions of the flange are in different positions. What is the layout of holes on actual body of the lens it self? Are there "both sets" of holes on the updated lens, or just new set? I would like to now this before actually removing the new flange off of my lens...
I hope I made it clear?
Thanks in advance!
 

250swb

Member
Th

So two different flange designs at the mount interface for the lens id coding has nothing to do with the fact that the two 28mm lens flanges have the correct shape on the frame line selector bit.

G
Congratulations if you understood that, I didn't.

The lens needs to bring up the 28mm frameline, which the new version does, or it won't be able to be coded not matter what the code you enter is.

To the OP, just unscrew the flange and look to see if there are another set of holes. But I'm not sure why you need to have another flange machined and coded? The one you have should be correct if it does indeed bring up the 28mm frameline, then you only need to mark the code for a 21mm lens with paint in the machined groove?

Steve
 

sisoje

New member
Steve,
Both my flanges are NOT six bit coded. I want to send the "old" extra one for drilling (to John) before I actually remove the "new" one from the lens.
I am hesitant to take the (new style) flange and send it to John, because if it gets lost I will be stuck with useless lens... Zeiss is not selling these flanges as spare parts any more...
Everything is more complicated with sending stuff since I Am in Canada.


Steven
 

250swb

Member
Yes but if the new one has a recess as you say it has that is what you use to code it. The recess is to stop the paint rubbing off when you mount it on the camera, it is there for exactly that purpose.

It is only one black mark that you need to code the 21mm, you don't need specific slots machined in, nor do you need to put white marks on. You can find the simple template you need to make out of paper, plus lens codes, here

BoPhoto.com: M8 coder - simple manual handcoding of M lenses

All you do is put the template on the lens, put a dab of black paint in the groove on the flange (sharpie type markers often don't work with the M9, you need a more opaque black) where the code marking needs to go, and wait for the paint to dry.

If the previous owner tried it before he may not have used an opaque black so it doesn't work. But if he put it in the wrong place or was experimenting with different codes you need to rub that code mark off first. But to reiterate, if the lens brings up the 28mm frameline it is correct, if it has a groove machined in the flange this is correct and is meant to be used for coding, if you use black paint (matt black hobby type paint is best) again correct!

Steve
 

sisoje

New member
Steve,

You are 100% correct!
Previous owner "sloppy coded" the lens as 28mm... We all know it's wrong. I could go the route you suggested, and thank you for the link.

BUT, I am kinda OCD perfectionist and if I go the route of "auto lens detect" I rather have the proper work done by Mr. Milich or I would just stay as it is know (that works as well) by manually selecting a 21mm in the camera's menu...

Question for Mr. Milich: do you have your bronze flanges for Zeiss 21mm in both "holes set ups"? Please, advise when you have time.

Regards,
Steven
 

250swb

Member
I sense you haven't grasped how easy it is. This is the back of my 21mm ZM f/2.8

The coding mark is painted into the groove, that is all that is needed to code the lens, it is detected automatically as a 21mm f/2.8 lens by the camera.

Steve
 

jlm

Workshop Member
my stock of zeiss flanges has the earlier hole pattern. i have see a couple with the new hole pattern, but haven't made any of them yet. it is quite possible the lens has both hole patterns, but i don't have a newer one to check. an alternative I might follow is to put both hole patterns in my flanges, including my existing stock
 

250swb

Member
an alternative I might follow is to put both hole patterns in my flanges, including my existing stock
What do people then do about the light leak problem of the flange hole overlapping a bayonet screw hole on Leica bodies on the earlier pattern flange? And doesn't one of the early version flange holes overlap the code detector anyway?

Steve
 

jlm

Workshop Member
the old pattern has a screw located in the photodetector pattern, paint codes right on the screw worked fine. But you are right, an un-used hole at that location would mess up the code detection, so it looks like two types of flanges are needed.

what some have done is to use only three out of the four screws and simply plug the old hole in the flange which is in the area of the detectors.

not sure what you mean about the "flange hole overlapping a bayonet screw hole on Leica bodies..."
 

250swb

Member
not sure what you mean about the "flange hole overlapping a bayonet screw hole on Leica bodies..."
I think this was the original problem and why the mount was changed, and nothing to do with the coding detector as such. A screw on the flange and a screw on the bayonet mount overlapped and at the right angle and intensity light would get in and cause a flare that baffled people for a while. So the mount was modified and at the same time a rebate was machined in to allow coding like the later CV M mounts.

Steve
 

jlm

Workshop Member
i don't have an M8/9 to check, but on the M7 the old zeiss flange does not overlap with the leica bayonet-to-body screws
 

sisoje

New member
Thanks everybody for the input!
I guess, I will have to remove the "new type" flange off my lens and see if the "old type" (my spare) fits on the lens (if it has "old layout" holes). If yes, it's easy! I will send the old flange to John ASAP. If it does not fit, then change of plan...

Thanks.
 
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