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After several failures hand coding the 6bit on a Zeiss Biogon 2.8/35 with black markers, paper etc., I have decided to make a proper pattern of recessed forms in de flange using a mill.  However I am not absolutely sure about the layout.  I seem to remember that somewhere at the net or maybe even at this forum somebody posted the exact layout with dimensions and angles and even tolerances but I cannot find it anymore.  So if somebody knows what I mean and still can find it, I would very much appreciate.  What I have done so far is to take the jpeg picture from bophoto and measured it.  The difficulty is to measure angles accurately but I hope these results might be correct where there is 114° between the center lines of that open recess and the first bit recess.  Then there is 5° between each bit.  I assume that these angles are valid for all types of flanges?  Any comments?  Sorry about the big size of the drawing.

Charles

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Thank you, I had seen most of it.  Unfortunately, the Zeiss Biogon I have has a flange with integrated internal threading for the focus regulation which my (Chinese?) replacement flange has not and is thus useless as I don't want to transfer the original flange threading (if this were possible but I don't think it is).  Moreover it is nearly 0.4mm thicker which makes 20% over a total travel of the focussing of about 2.1 mm, too much and the flange cannot be made much thinner because then the screw heads would fall through.  The original flange has a circular recess apparently to use that for black painting but I have been unable to create markings which are recognised.  So my idea was to make the 6bit on the original flange.

Charles

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4 hours ago, auceps said:

Will van Manen codes 3rd party lenses. I am afraid that one of the 4 srews in the coding area will be damaged be that prodedure. Zeiss (Cosina) should change the position of the mounting screws!

Hahahahahahahahahahahaha.

No. 

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I know Wil van Maanen does it.  I think I have a Voigtlander 1.2/50mm which I bought used in the NL and which was coded, probably by him as he is in the NL as well.  I can do it, I made some proper test dimples for testing, no problem.  But I cannot decide on the 114°.  I checked this position on the 2 Leica 6bit coded lenses I have and it seems 113° would fit better.  Confused.  And, btw it would be difficult for Leica to have threading holes in the coding area, so why should Zeiss have holes in that position?

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17 hours ago, charles_nl said:

I know Wil van Maanen does it.  I think I have a Voigtlander 1.2/50mm which I bought used in the NL and which was coded, probably by him as he is in the NL as well.  I can do it, I made some proper test dimples for testing, no problem.  But I cannot decide on the 114°.  I checked this position on the 2 Leica 6bit coded lenses I have and it seems 113° would fit better.  Confused.  And, btw it would be difficult for Leica to have threading holes in the coding area, so why should Zeiss have holes in that position?

I have the same problem with a 2.8/90 Tele-Elmarit; on some M240s it is sufficient to paint the screw with a sharpy to get the appropiate coding, but on my M240 it is not. To change the flange changes the focus - I don't like that. Possible solution would be to do the devignetting in Lightroom etc. and to transfer to setttings to EXIF by software.

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After measuring angles on 2 real Leica 6bit coded lenses, I have corrected the 114° above to 115° and coded my dummy Chinese Biogon flange accordingly as a test.  It seems to be correct as the M10 accepted the correct code.  The other lens I want to code is an Elmarit 2.8/135 which has a different flange and indeed a screw in the 6bit areas, somewhere in the midst of the 3rd and 4th bit, which is unfortunate because that needs to be the black.  The Chinese flange I have on order has omitted that hole and comes with only 5 holes.  Maybe you could fill the grooves of the screw hole with some black non-drying children's clay or  black non-drying wood filler?  The black really needs to be black.  Or, sacrilege, leave the screw out and fill it completely.

 

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The angle 115° for the coding area is ok; see the following contribution in the LUF with many details:

M Flanges and 6-bit coding - Leica M Lenses - Leica Forum

In my case the screw in the flange of the Tele-Elmarit is too small. I hope to find an appropriate flange Type II for my lens.

My idea was to print the lens codes on an adhesive plastic foil with my laser printer to keep the original state of my vintage summicrons. Unfortunately I didn't succeed.

Screws in the coding area may cause problems by fooling out the lens detection! Of course Zeiss could change the position of the screws. Perhaps there is a secret agreement between Leica and Zeiss - patent protection. Coding of Zeiss lenses may be tricky: the lens detection for The Biogon 25 works, if you use the lens with the 35 mm frame (M3 legacy) - Zeiss delivers the Biogon 25 with th 28 mm frame.

Good luck!

Edited by auceps
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1 hour ago, auceps said:

 

Screws in the coding area may cause problems by fooling out the lens detection! Of course Zeiss could change the position of the screws. Perhaps there is a secret agreement between Leica and Zeiss - patent protection. Coding of Zeiss lenses may be tricky: the lens detection for The Biogon 25 works, if you use the lens with the 35 mm frame (M3 legacy) - Zeiss delivers the Biogon 25 with th 28 mm frame.

 

The older Zeiss M lenses did have a screw in the wrong place for coding, but the newer lenses (for many years now) have a groove machined into the flange and the screw holes are moved.  This may not be universal, but covers the majority of the range.  This means coding can be done by simply putting dabs of matt black enamel paint into the groove at the appropriate places. This does in fact work and the paint doesn't wear off. Using a marker pen and not paint is rarely going to be successful. Zeiss could also at one time convert lenses to the newer flange. And to finish the 25mm Biogon does not bring up the 28mm frameline on an M3 for obvious reasons.

Edited by 250swb
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A more general question: how can I edit my posts?  I see sometimes an "Edited" comment below a posting, so it should be possible and I want to edit my 1st post to correct the incorrect 114°.

I coded my Zeiss 2.8/35mm and a Voigtlander 1.5/50mm using the original flanges.  I milled the 6 bits, painted them, they are correct and I am quite happy with the look of them.  And the accompanying complications are actually part of the fun.

Charles

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the flange was clamped on its rim with 3 standard clamps centered on the centered rotary table.  The indent on the flange was used as reference (at -Y), the clamps were on +-X & +Y.  The milling was done with the position of the bit rotated to -X but therefore the -X clamp had to be moved to -Y.   I used a 2 mm endmill which was displaced over 1 mm, giving the 2x4 mm as extremes with a 0.3 mm depth setting.  A 1.8 mm would have been better, the 2 mm left just a very tiny wall between the adjacent bits.  I painted the odd ones first, let them dry a few hours and then the in between ones to avoid paint overflowing.

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In my last post submitted 2 minutes ago, I see after the + sign at the bottom  2 options in red: "Quote  Edit" but in all my other posts in this topic (inlcuding the #1) there is only "Quote" after the + sign.  Why can I not edit the others?

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