Coded lens flange

[Mikep996]

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I recently ordered one of the Chinese lens flanges with the coding "indents."  It had an "expected" arrival of a month but showed up in 10 days.  Quality looks good though, of course, I have no idea if it's as precisely made so as to not adversely affect rangefinder focus.  But heck, for 16 bucks I figured it was worth trying.

Now I have to decide which lens to mount it on!  My uncoded lenses are the MATE, a 50 Summicron, and a 90 Elmarit M.  Seems to me that the logical choice would be the MATE since it has the 28/35 which, from what I understand, the wider lenses benefit from the coding.  The camera will remember the last uncoded lens that was installed/selected on the code list and I figure that whichever it remembers -  the 50 or the 90 - it has no effect on the photo since both focal lengths are longer than 35.  SO whether the camera thinks there's a 50 or 90 mounted there is no actual internal adjustment made, again, AS I UNDERSTAND IT!

Does that sound logical/correct?

FWIW -I can't see any obvious difference in a 'normal' photo with the 28mm MATE whether selected in the code list or with coding off.  But in full Geek-mode, I worked hard at trying to find a difference and, when tripod mounted shooting a white brick wall, I can see vignetting/softening at the edges which disappears when I select the MATE's 28 in the code select list.  

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[TomB_tx]

Remember, the machining of one of the flange locking "ears" determines the frame lines that appear in the VF, and the M10 also senses the frameline selection along with the coding for lens identification. So your flange should have been ordered for a specific focal length: 50, 35, or 90. That would determine which lens to use with it.

[NigelG]

Remember that the lens flange will mechanically set the rangefinder mask to 50/75, 28/90 or 35/135....that’s why the MATE has the sprung section of flange that moves when rotating the focal length selection so as to change the mask to the relevant pair. This is entirely seperate from the 6-bit coding which differentiates between lens corrections + adds the EXIF data tag.

You need to check which of the 3 flange options you purchased - the relevant pair will be marked somewhere. If you have a 28/90 flange and you fit it to your 50 summicron and mount it you will see the 28/90 framelines in the VF not the 50/75.....

[NigelG]

Well TomB_tx beat me to it.😀

[Mikep996]

AHA!  Well...didn't know that!   So I'll have to figure out what I actually bought.  Thanks, guys.

I purchased:  Detachable 6-bit code Leica M Mount Lens Adapter 28-90 90mm 6-hole.  I ASSUMED (yes, I know what they say about assumptions) that it meant it would work on any lens from 28mm to 90mm.  The frame line thing never occurred to me so I wonder what I have?   90mm?

Edited June 7, 2020 by Mikep996

[TomB_tx]

Both 28 & 90 frame lines show at the same time, so this flange would work with either. A different flange would work for 35 or 135, and a third type with 50 or 75.

Notice that the “frame preview lever” under the front VF has only 3 positions, for the 3 different flanges. That’s why the frame lines show in pairs.

Edited June 7, 2020 by TomB_tx

[Mikep996]

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What frame lines would show if I put on the MATE?  Would the frame lines change when shifting between 28/35/50?

[TomB_tx]

The MATE has a special articulated flange that changes based on lens setting. Not compatible with an aftermarket flange.

Leica made several lenses with flange designs incompatible with these aftermarket replacements, due to hole pattern, thickness, or other differences. I have at least 3 from the late 60s-70s like that.

Edited June 7, 2020 by TomB_tx

[Mikep996]

Thanks!  Really appreciate the info.  Sounds as if I have a flange that doesn't do anything I really wanted though I might as well put it on the 90 El M to have the Exif data. 

[jaapv]

4 hours ago, Mikep996 said:

What frame lines would show if I put on the MATE?  Would the frame lines change when shifting between 28/35/50?

You would have to send your MATE in for repair afterwards. The frameline transfer mechanism in the flange is quite sensitive and needs to be adjusted properly to function correctly. Mess with it at your peril.

[adan]

The Tri-Elmar 28-50-35 has a unique lens flange with a moving part. Therefore it cannot be converted to 6-bit coding except by Leica - it needs a dedicated complex flange no-one else makes.

For single-focal-length Leica lenses, there are three types of flange: one for lenses 28 or 90, one for 35 or 135, and one for 50 or 75. Lenses wider than 28mm take flanges that fit into that system - even though they trigger only irrelevant framelines. e.g. 24mm lenses behave like 35s and 135s; 21mm lenses behave like 28s and 90s, and I don't know for sure about the 18 and 16/18/21 Super-Wide-Tri-Elmar). But at any rate, third-party replacement flanges should work OK on such lenses.

There is mechanical historical contingency to all this - choices Leitz/Leica made in the 1950s that they (and we) are stuck with today, if they want to retain backward-compatability with all their M lenses.

Leica built the M3 to have three framelines, for focal lengths 50, 90, and 135. And thus designed the automatic triggering of framelines to only need three types of flanges.

Along came the M2 with a new, wider viewfinder that could handle a 35 view. But since Leitz was now stuck with just 3 possible flanges, they had to piggyback 35 framelines onto the 135 match (but in the M2, left out the actual 135mm lines).

Then in 1968, the M4 was introduced to replace both the M3 and M2, with frames for both/either 35s and 135s, as well as separate and distinct 50 and 90 frames. And at that point, Leitz looked a little way into the future and decided that if 28mm lines were ever going to be added, they should pair with the 90mm lines, to minimize visual confusion, as with 35/135. So from that point, 28mm lenses were made with the 90mm flange, even though there were not yet any lines for a 28mm in the finder.

At any rate, now we have 3 pairs of framelines, and 3 types of mounting flange, to cover 6 focal lengths: 28/90, 35/135, and 50/75. That last pairing drives some people crazy - but 50/75 was the only "pair" still available, when the 75 Summilux was introduced in 1980. The others were already permanently paired up.

[michali]

5 hours ago, jaapv said:

You would have to send your MATE in for repair afterwards. The frameline transfer mechanism in the flange is quite sensitive and needs to be adjusted properly to function correctly. Mess with it at your peril.

 

10 hours ago, Mikep996 said:

What frame lines would show if I put on the MATE?  Would the frame lines change when shifting between 28/35/50?

I agree with Jaap's advice, do not mess with the MATE's flange under any circumstances.

Many years ago (M8 days), I purchased one of these M Lens Coder  I'm not sure if they're still available.

I've successfully coded most of my non-coded M lenses including the MATE which brings up all 3 frame lines. There are however 1 or 2 lenses which are stubborn & it just won't work on those e.g. my recently acquired Voigtlander 75mm F/1.5 ASPH VM, which I've tried to code as a 75mm Summilux f1.4 .....nothing doing.

Do some research on DIY coding, there's plenty information out there.

[tedd]

I have thought about those coded flanges a few times and always see a bunch of comments from people saying that they're the wrong thickness and not to bother. Has anyone here used them successfully and without any focus error as a result?

[250swb]

I use them on some lenses and haven't had a problem, others will swear they never work. Given people will pay hundreds of pounds on a new bag every year the price of a replacement flange is pretty insignificant not to simply have a go. I think the functioning is dependent on how they are screwed on even though it is a simple job. Use the correct cross head (+) #00 screwdriver and tighten the screws down gradually opposite to opposite where possible, this centres the flange on the lens so you don't get a notchy focus ring . Use matt black paint to fill in the coding rebates, not Sharpie. If you can't get accurate focus put the original back on following the tightening instructions above. For replacement flanges the Jinfinance brand seem to be fairly reliable, although as I said before some will swear they never work.

[onasj]

I suggest you carefully compare the thickness of the third-party flange to that of the uncoded original you are replacing. If it’s too thick as these tend to be, you can carefully sand the backside down to the proper thickness (you’ll know because infinity focus won’t be reachable until it is). If too thin you can construct a shim from tape or foil.  Regarding the frame lines, you can convert a 28/90 flange to a 50/75 flange by simply removing a couple mm of metal from the frame line selection cam using a handheld rotary tool. Carefully inspect your various Leica flange mounts and you can see what needs removing.  On a $16 third-party flange it is not a very risky experiment.

[tedd]

1 hour ago, 250swb said:

I use them on some lenses and haven't had a problem, others will swear they never work. Given people will pay hundreds of pounds on a new bag every year the price of a replacement flange is pretty insignificant not to simply have a go. I think the functioning is dependent on how they are screwed on even though it is a simple job. Use the correct cross head (+) #00 screwdriver and tighten the screws down gradually opposite to opposite where possible, this centres the flange on the lens so you don't get a notchy focus ring . Use matt black paint to fill in the coding rebates, not Sharpie. If you can't get accurate focus put the original back on following the tightening instructions above. For replacement flanges the Jinfinance brand seem to be fairly reliable, although as I said before some will swear they never work.

Just ordered three. I figure for $90 AUD it's not much of a risk when Leica quoted me $1200 to have the same thing done.

Edited June 8, 2020 by tedd

[Mikep996]

I certainly was not aware of the intricacies of the Leica frame line system although it makes perfect sense from a mechanical point of view; I had never really thought about it before.  In the Film days it was much simpler - didn't need no stinking coded lenses!  

As suggested, I have no intention of messing with the MATE flange and, until reading the info folks have provided here, I never even looked at it to see that it is different than "normal" lens flanges.  So the MATE will have to remain un-coded - at least as far as a new flange or Leica modifying it. But as others have stated, putting replacement flanges to get coding on prime lenses is quite inexpensive and easy enough to do...or undo!

Great info re all this!  I really appreciate it.  Amazing what I'm learning about something I paid absolutely no attention to in years of shooting with film Leica's in the pre-digital age!

Edited June 8, 2020 by Mikep996

[onasj]

One major upside of coding your MATE is that coding will allow the selected focal length to be recognized by newer M models and recorded in the EXIF data of each photo, assuming the frame selection mechanism on the MATE is working properly (requires both a working frame line selection mechanism and 6-bit coding).

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[Mikep996]

This morning I removed the original Leica flange on my 90mm Elmarit M and, before going further, compared it to the Chinese flange.   I measured at 12, 3, 6, and 9 o'clock positions on both flanges.  The Leica flange's 4 measurements were: .99mm, 1mm, 1.01mm and 1mm.  The Chinese flange measured 1mm in all 4 positions.  I coded the new flange with some black paint in the appropriate grooves - didn't use white at all.  Only black paint I had on hand was some Rustoleum gloss black spray.  I sprayed some into a bottle cap and dipped the tip of a toothpick in the paint to apply it.  Paint was dry in a couple of minutes. I installed the new flange on the lens and the camera recognized it correctly.  

I'm going to order another flange for my 50 Summicron.  The MATE will remain my only non-coded lens of the five lenses I have but I'll manually set it at the 35mm MATE selection in the camera  so it will will remember that setting if I mount the MATE. I found that with the camera manually set at the MATE 35mm and shooting a white wall, I can't see any difference that would ever be visible in a picture regardless which MATE focal length is selected.  If set manually at 50mm, there is MAYBE enough vignetting using the 28mm focal length to notice if looking critically at certain types of photos.

 I was one of the people that said "I don't care about EXIF data," but the process is so easy/cheap that, IMO, it's worth doing to any non-coded lens, even if you don't care all that much about the EXIF! At the cost of 15 bucks, I'm happy to have the EXIF data.

Edited June 11, 2020 by Mikep996