Coding CV 21mm for M8 - does the mount really matter?

[gdi]

I have read that the software in the M8 uses a combination of the 6 bit coding and the frame lines selected to apply software corrections for UV shift and vignetting. It doesn't makes sense they would do that - it would have required adding electronics to the frame selector when the coding is really all that's needed - but who knows.

My questions are: Can I be comfortable that the camera will apply corrections if the menu selection is set to lens detect and ir filter, and the camera is displaying the focal length? Also, what is the general recommendation for coding the CV 21 - will Wate work?

 

[ampguy]

The WATE coding menus bring up a sub-menu for 16/18/21.

There is no coding for CV lens.

Once coded, and detected, you need to shoot some white walls at 16/18/21 and maybe an SA and determine which you like the most. There is no "best"

Many people revert to no coding on the M8, and turn out perfect photos.

 

[maggieo]

I've coded my CV 21/4 Color Skopar as an Elmarit-M 21mm f/2.8 ASPH. (0=white 1=black 011000) I've gotten fantastic results. My CV15 is coded as WATE and I use it on the 18mm setting with great results.

 

[gdi]

The Leica 21 Elmarits, pre-asph & asph, and the WATE bring up the 28/90 frames, however, the Leica 21/3.4 Super Angulon and the Zeiss ZM 21/2.8 Biogon both bring up the 50/75 frames, which precludes them being coded as a Leica 21 without changing their mounts.

I have coded both my M mount 21mm's, the SA & the Biogon, as the 18/3.8 Super Elmarit, which brings up the 50/75 marks. Both lenses produce RAW files with my M8.2 that are clean in the corners, no perceived color shifting. I do have my CV 15/4.5 coded as the WAT (and select the 16mm option from the camera's menu) and it too creates images with consistent colors through the corners.

I don't know what frames the CV 21 brings up but hopefully the above will be helpful.

--Steve

thanks - I do have a 28/90 adapter on the 21 - it is recognized as WATE - like my 15 4.5. I am glad to hear about the Biogon coding as an 18 working well - the only think that has kept me from getting one has been the stories of changing mounts.

So am I correct in assuming that if lens detection is working, then the software corrections will work as well, right?

 

[gdi]

I've coded my CV 21/4 Color Skopar as an Elmarit-M 21mm f/2.8 ASPH. (0=white 1=black 011000) I've gotten fantastic results. My CV15 is coded as WATE and I use it on the 18mm setting with great results.

Thanks Maggie, I was thinking I would code it as WATE due to it being F4 like the 21, I may try the Elmarit code for kicks.

 

[zleica]

I also use an 28/90 adaptor, coded as WATE, for my CV21. It works well. If you coded as 21/2,8, perhaps the software has stronger correction factor. I do find that coded wide angle lenses have better color rendition.

 

[Doug]

I have read that the software in the M8 uses a combination of the 6 bit coding and the frame lines selected to apply software corrections for UV shift and vignetting. It doesn't makes sense they would do that - it would have required adding electronics to the frame selector when the coding is really all that's needed - but who knows.

And it IS true; the frameline brought up by the mount must be compatible with the 6-bit coding for it to work and be properly recognized. As mentioned, there are various codings that can work, but whichever you choose, the mount must match.

 

[maggieo]

Thanks Maggie, I was thinking I would code it as WATE due to it being F4 like the 21, I may try the Elmarit code for kicks.

The Elmarit code works aces and you don't have to remember to set the menu every time you turn the camera on, like you do with WATE-coded lenses.

 

[gdi]

And it IS true; the frameline brought up by the mount must be compatible with the 6-bit coding for it to work and be properly recognized. As mentioned, there are various codings that can work, but whichever you choose, the mount must match.

Should be easy to test right, Doug?

I can just hold the frame preview lever to the wrong frame when turning the camera on and then take a shot. I should not see the focal length in the image info if it isn't the correct frame lines. I'll try that today - I don't doubt that it's true, it just seems so pointless for them to do it - unless they planned to eventually have more lenses than 6 bits will accommodate.

Thanks


EDIT: I did test it and confirmed that you are correct Doug - it recognized the lens, but assigned the wrong Focal Length. You learn something everyday!

 

[gdi]

The Elmarit code works aces and you don't have to remember to set the menu every time you turn the camera on, like you do with WATE-coded lenses.

Thanks Maggie I'll give it a try.