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DIY 6-bit coding: is it worth it?


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Over the years, I've acquired a few lenses, both Leica and non-Leica, that are not 6-bit coded.  Specifically, a black paint Summicron 35mm, a Voigtlander 21mm, and Zeiss Biogons, 25mm and 28mm.  At some point I got interested in DUY 6-bit coding and did some research, which lead to buying replacement back rings for them, as best I could see a match on eBay, and some paint to paint those.  I never got around to it, primarily for the worry that opening the lens should be done in clean room and that the Chinese-made replacement rings would not be of the right thickness, throwing off focus.

Is it a good idea to use those generic 6-bit adapters, replacing them yourself, and hoping that will work, or would you rather ship them to Leica?  Also, what about non-Leica lenses?  Can you ask then to do those too and assign a lens of your choice?

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I would not mess up a perfectly good and original lens mount.
I would not send it to Leica either - although I did so when the M8 came about or when I felt a lens needed to be perfectly (re-)calibrated - mainly due to the cost involved. Instead, I would send it to a third-party competent technician who would charge a more reasonable amount for the service.
Leica will not touch a lens that didn't come out of their own production line in the first place.
AFAIC, I have made it a habit when switching lenses to set the code manually in the camera menu.

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11 minutes ago, Ecar said:

I would not mess up a perfectly good and original lens mount.
...
AFAIC, I have made it a habit when switching lenses to set the code manually in the camera menu.

That’s why I hesitated.  The problem with menu setup is I forget to turn it off and it stays manual, not allowing the 6-bit coded lenses to override it.  I have to use LensTagger in Lightroom to restore what I remember were the right lenses.  That ‘s why I need some kind of coding...

Which service would folks recommend?

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I never sent uncoded lenses to Leica or third parties due to the cost, I simply use the lenses as they are. Of course, I do not get the lens' Exif information, but I don't miss it, and any automatic correction (which I feel is overrated) of the image in a post processing program I can do manually under own control.

In case you do by yourself with third party flanges there is no clean room required, but it is essential to use high quality drivers f the exact size (my choice is Swiss Tools), otherwise you ruin the screws. I once compared several replacement flanges from Chinese venders with Leica ones, they were all in the same tolerance range of 0.98...1.02 mm, checked with a precision caliper. 

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Some of the Chinese flanges work because they are the correct thickness, and some don't because they aren't, the only thing you can do is try. It's a five minute job and doesn't let dust into the innards of the lens. As Andreas says the only tool you need is a good precision screwdriver, as I recall it's a +# '00' size (but cross reference that). Unscrew the Leica flange and place the new flange in the same orientation, then gradually tighten the screws going from opposite to opposite as much as possible, this centres the flange, if you tighten one screw, then the next you are likely to get an uncentred flange that causes a tight or notchy focus ring. Be confident with the screwdriver, firm but gentle. Use matt black modelers paint in the coding rebates, don't shortcut with a marker pen. If it doesn't focus properly change it back again. 

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1 hour ago, setuporg said:

Which service would folks recommend?

I live in Europe, so I'm not too familiar with US technicians, but Don Goldberg (DAG) comes to mind. I'm sure there are others.

Regarding tolerances, some Chinese eBay sellers are OK (FWIW, I have mostly been happy with jinfinance for LTM to M adapters), but it really depends on how critical focus is for the lenses under consideration. For example, I had the coding of my Noctilux 50/1, Summilux 75/1.4 and Summicron 90/2 done by Leica several years ago, knowing that they would check focus and adjust it as required. They came back perfect.

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2 hours ago, 250swb said:

Some of the Chinese flanges work because they are the correct thickness, and some don't because they aren't, the only thing you can do is try. It's a five minute job and doesn't let dust into the innards of the lens. As Andreas says the only tool you need is a good precision screwdriver, as I recall it's a +# '00' size (but cross reference that). Unscrew the Leica flange and place the new flange in the same orientation, then gradually tighten the screws going from opposite to opposite as much as possible, this centres the flange, if you tighten one screw, then the next you are likely to get an uncentred flange that causes a tight or notchy focus ring. Be confident with the screwdriver, firm but gentle. Use matt black modelers paint in the coding rebates, don't shortcut with a marker pen. If it doesn't focus properly change it back again. 

While I would agree with what Steve has written I also add a note of caution.  I changed the flanges of several lenses to 'Jin Finance' ones easily and without a problem and the focussing was still spot on.

The only one I had a problem with was my f/1 Noctilux because I didn't know that it had shims under the flange.  Lining up the screw holes, the shim holes, and the flange holes was tricky to say the least but I managed it only to find that focus was well off - possibly owing to the presence of the shims - so I had to change the flange back with all the hole lining-up difficulty all over again.  I'm happy to say that my Noctilux is back to where it was before I started and will remain uncoded.

My other lenses were simple: undo screws, swap flange, redo screws, job done.

Pete.

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After testing a 90 Apo to see if it focused well with my M240 I changed to a 6 bit  coding ring, the focus was off. I put the original ring back, its focus is again perfect. I do like the info recording portion of 6 bit, the correction I’d rather do myself when necessary. 

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I have a couple of non-coded lenses.  My approach is to manually select a Leica lens (that I don't own) that is the same focal length so I can select the images with incorrect lens EXIF data .   In Lightroom I use the LensTagger plugin and apply a EXIF pre-set with the correct data.  The plugin uses ExifTool as its basis, which can be run standalone for users of other raw processors. 

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I don't bother with any of that - have lens selection turned off.  I shoot for print.  I make fixes in PS, print tests on small (letter size) proofs until I get a 'AH!', then go for it on good A2 paper. 

People come over to my home gallery when a series is done... its fun to share & get useful feedback.  Many of my friends are artists & sometimes people buy them.  I get a kick from seeing my stuff framed nicely in other people's homes, sometimes years later.

Prints!  Not online where most people's monitors aren't properly calibrated or worse yet, a 2 second glance at someone's cellphone mini images.  Why bother?

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I have done three older M lenses (35,50,90) with JinFinance flanges and all work well. You must get ones with the correct screw holes aligned for your lens; use dense model paint (humbrol works well) and mic for correct thickness. Mine read on M9,M240 & M10P. Good luck 😊

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I have done four Leica M lenses (28 f2.8, 35 f2, 50 f2, 90 f2) with JinFinance flanges as well and they've worked great and are spot on. However, with the 90mm f2.8 tele-elmarit the JinFinance flange shifted the focus. I tried a couple with the same results, so I just stayed with the original.

The flanges are so cheap and the process is so easy, it's really no big deal to give it a try. If you find one doesn't work for you, you're only out a few bucks and about 20 minutes of time.

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