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Coding a zeiss 21/2.8?

glenerrolrd

Workshop Member
I am trying out a zeiss 21/2.8 zm lens and its off for 6 bit coding. I have assumed it should be coded as a Leica 21/2.8 asph but the question was raised...should it be the pre asph or the asph code. Surely this is splitting hairs but I thought I should ask. Sean Reids article shows he used the asph but the repair service said others are using the preasph?
 
R

roey

Guest
I don't know the answer, but can you share where you are getting it 6-bit coded?

Thanks!
 

gero

New member
I am in the same boat. I sent the mounts only to Jhon Millich [email protected]
but I don't know if I have to add sement to the screws before I put them on again. Also is the mount for the 25 the same as the 21?
 

glenerrolrd

Workshop Member
I sent my lens to DAG camera repair. I believe he sends the mounts to milich for machining. You need to have the correct mount ..you may have to search the forums to find which mount is required for each focal length. Generally you have to get a different mount from Zeiss and then have the new mount machined. I decided to let DAG handle the conversion because he will calibrate the lens after the mount is changed . He is doing my 18 and 21 .
 

Stuart Richardson

Active member
I had John do it as 21mm ASPH -- it worked quite well. I think the 21mm ASPH is probably a better analog than the 21mm non-asph. The Zeiss and the ASPH are very similar in performance and character, any corrections applied by the camera would probably be more accurate than with the earlier version. For example, you would rather have it under-apply vignetting correction than over-apply (you would end up with lighter corners...it would look weird), and the old lens probably has more vignetting, so it would be worse to use for the coding.

As for the 25 and the 21 mounts -- they are different. John and I went back and forth with this...suffice to say they are not the same. Just have him put the right mounts on each.
 

jlm

Workshop Member
i found one of the two mounts that appeared identical had a very slightly larger inside diameter than the other (about .010") i am now enlarging my 18 mm mounts by .010 so they will fit either the 18 or the 21 lens. the screw pattern is accurate enough to ensure centering
 

glenerrolrd

Workshop Member
why would you want to swich mounts?
For the 6bit coding to work the lens must bring up the proper framelines. I am not positive (check other posts on LUF) but the correct frame lines for the 18 and the 21 are the the 28/90. I think the zeiss mount brings up the 24/35. So you need both a mount change and the coding for the camera to apply the adjustments. The 25mm comes with the 28/90 flange but needs he 24/35 to be coded. You have two options for permanent coding(1) buy the correct mount from zeiss and have it milled or (2)buy a new mount made by John M as he indicates above. But I would read the long posts on the LUF and the reviews on Reid Reports. I think Guy also had a detailed post on the 18 here.
 

Guy Mancuso

Administrator, Instructor
I do have a thread on the 18mm here. John made me a new mount and coded it for me. Worked very well. I got the correct framelines for it and also had it coded for the WATE which the default is 18mm without doing any settings. Worked out great because all i had to do was mount it and automatically went to the coded 18mm setting. I used a step up ring from 58 to 60 with a Leica 60mm IR filter. This gave me no vignetting at all and perfect results in the corners on cyan drift
 

Chuck Jones

Subscriber Member
Folks, I am going to toss my own opinion in here, though please understand that I qualify my advice as I have not tried myself to code "off brand" lenses.

Personally, I would recommend not coding them at all. Those codes were designed to correct individual lens characteristics in the specific Leica lenses they are assigned to. And more than just those pertaining to the focal length. I would suggest for your consideration that any software compensation due to reading the code is going to adjust your image file in a manner that will only serve to over-correct and distort your image when used on another lens. These codes were developed specifically to "tune" the final image file a specific direction. There is no way a Zeiss lens is going to need exactly the same corrections that a Leica 21mm will need. I point out to you that there are at least two 21mm lens codes. Ask yourself why. Because the Leica engineers found that there was enough of a difference in the two lenses that they needed to have two codes. And no code whatever for my most loved 21mm f3.4 SA. Any correction I feel is needed to the image files from my SA I do myself in my post processing programs.

Rant switch on :lecture: My second objection to doing this is an artistic one. Who among us as artists want to see final prints that all have the same look, coming from many different photographic artists? If I pick up another magazine, and stare at the cover image thinking "Yep, another 1DsIII photo" I think I am going to scream.:cussing: Everyone shooting the exact same camera, with the same lens selection, results in everybody having pretty much the same lens signature look to the whole bloody world's body of work from this period of time. :sleep006:

Why do I prefer using the older Leica glass, for the most part? Because they ARE different, each with it's unique drawing, contrast, flare, flaws, color shifts, IR bleed, and blacks that turn the whole world purple, in just the perfect light. For myself, as an artist the M8 is the perfect artistic tool, warts and all. Heck, the warts are what makes it challenging for me. What can I create using a lens that is almost as old as I am? Yea, I could code it and yes, that too would be yet another distorted view of reality, another artistic tool. But I think the engineers at Leica have done a magnificent job of designing these artistic tools just they way they are. I think they are pretty well perfect, just as they are intended to be right now. Who am I to argue with perfection? :lecture: Rant Switch Off. Just my own opinion, your own may vary. But for me, I have no interest in even trying to make my 21mm f/3.4 SA look like a 21mm ASPH. I Love it just the way it is .... warts and all.
 

Stuart Richardson

Active member
Ok, that all may be true, but the using the codes get you from heavily blue, vignetted corners to a more or less even, neutral image. From there you can do whatever you want. The 21mm ASPH and the 21mm Biogon are extraordinarily similar lenses -- I have used both -- the coding acts very well on both of them. This coding is not a distortion correction -- it only acts on color shift and vignetting. Since they both are so similar, all it does is correct the strong cyan vignetting in the biogon and make it neutral. This is no different than using a center filter with a large format wide angle lens -- it's like using a center filter made for the 90mm Super-Angulon on the 90mm Grandagon. Sure, they are different manufacturers, but they are both 90mm large format lenses and the vignetting correction will be very similar. It is not "cheating". It is not going to make a boring photo great or a great photo boring -- it is just another tool.
 

dseelig

Member
I had Jon Milch code the 28 mount I got from Zeiss a Dn G
oldberg mont it on the lens for critical focus.I found that I ahd to put a small piece of tape over the part of the 6 bit coding where the screw was, otherwise the coding read as a 28 mm lens. I did this rather then nail polish as I did want it to be fairly easy process to remove the mount if it ever needed to be worked on. David
 

etrigan63

Active member
I ordered the proper mount from Zeiss and sent to John for milling. Prior to that I used Tim Isaac's M-Coder to hand code the lens to see which code worked best. I had to manually hold the framelines (brother, was that an act of contortion!), but I was able to determine that the 21 ASPH was the best setting.

Get lovely stuff like this now from it:
 

etrigan63

Active member
The 21mm Biogon has a tremendous IR hotspot, but you can still get really nice pictures from it. Especially in visible light. I have to find a 46-43mm step down ring so I can use my Hoya R72 filter on my CV 40mm Nokton which does not have an IR hotspot. Oddly enough, the Biogon actually has a focusing mark for IR photos on the barrel, and the CV does not. Go figure.
 
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