Archived posting to the Leica Users Group, 2010/11/15

[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]

Subject: [Leica] CV Ultra-wide Heliar (12mm) 6-bit coding on M9
From: ricc at (Ric Carter)
Date: Mon, 15 Nov 2010 08:06:11 -0500
References: <> <>

my completely unscientific observations:

the CV 12 & 15 seem to show less of the infrared color shift than leica 
lenses--need less filtration


On Nov 15, 2010, at 1:38 AM, Frank Dernie wrote:

> I have not played around much with the coding but have not been that 
> successful when I did. I quickly learned that, apart from having the 
> "right" info in the EXIF file, just setting the same focal length as one 
> of the Leica lenses is no guarantee of anything.
> On reflection it seems likely that the colour correction required is 
> dependant on the position of the exit pupil of the lens (hence the angle 
> of rays through the IR filter). This is entirely lens design dependant and 
> the focal length is only part of it, the 12mm CV lens has an exit pupil 
> -further- from the plane of focus than their 15mm lens, for example, so 
> the 15 behaves like a shorter focal length than the 12 in this respect.
> The amount of vignetting correction is also design dependant, with 
> symmetrical lenses having more inherent vignetting than retrofocus, but 
> both varying in detail following the exact optical design.
> Anyway it seems to me unlikely for -any- of the Leica lens profiles to 
> exactly match the requirements of 3rd party manufactured lenses.
> Cornerfix seems an altogether more practical solution if precise 
> compensation is the goal...
> In my case the vignetting doesn't bother me as much as the colour shift 
> because I am used to it anyway!
> cheers,
> FD
> On 13 Nov, 2010, at 17:54, Jean Louchet wrote:
>> Hi Vick (and all)
>>> On 11/9/2010 3:52 AM, Jean Louchet wrote:
>>>> Just to share my short experience, on my recently acquired M9, the CV
>>>> 12mm does require vignetting correction. After some disappointment
>>>> with coding it as the 16/18/21 (code 010000) and several other tests,
>>>> I coded it with code 011001 (recognised as a 2.8/24 ASPH) and the
>>>> results now look not perfect but very acceptable. Has ayone found a
>>>> better suited code?
>>>> I am using the same code for the CV 15mm as well.
>>>> Jean
>>> Date: Tue, 9 Nov 2010 08:17:30 -0500
>>> From: Vick Ko <vick.ko at>
>>> Very informative, Jean
>>> Do you use the same code for the M8?
>>> What method are you using?  Black marker?
>> As the M8 only uses the centre of the image provided by the lenses,
>> the vignetting of the 12 mm and 15 mm are not very disturbing on the
>> M8; however, a code that works on the M9 will work on the M8. The M8
>> will be less sensitive to using a (slightly) wrong code.
>> I agree with other list members that vignetting is not really an issue
>> from 50mm up on the M9 (and its equivalent 35mm on the M8) and hardly
>> perceptible on a 35 (M9) or 28 (M8) but it is really worth coding the
>> lens to correct vignetting for shorter focal lengths. I have never
>> been annoyed by any colour shift on the M9 even on extreme
>> wide-angles.
>> All my CV lenses are the old type, L39 mount so I have to use adapters
>> like the Voigtlander type II where metal has not been removed in front
>> of the code sensors (unlike the type I adapters and most original
>> Leica adapters). They are pre-engraved, so it is easy to mark them
>> using a thin black permanent marker. A cotton with alcohol will easily
>> remove the ink if willing to try another code. For both 12 and 15mm I
>> use a 35/135 adapter. I have a couple of older lenses (Minolta and
>> Leica) where I wrote directly on the mount, it works fine.
>> My own experience on adapters: my preferred are the Voigtlanders type
>> II, I found the Millich are well done but don't get the lens properly
>> oriented, and the ones sold on ebay by ***sweden or ADPLO have a rough
>> mating surface and don't have the right orientation either.
>> Oh yes, one last thing, the excellent site
>> has been updated a couple of days ago and now gives the codes of the
>> 1.4/21 and 1.4/24. I will try them with the CV12 and 15, and tell here
>> how it works.
>> Jean
>> _______________________________________________
>> Leica Users Group.
>> See for more information
> _______________________________________________
> Leica Users Group.
> See for more information

In reply to: Message from jean.louchet at (Jean Louchet) ([Leica] CV Ultra-wide Heliar (12mm) 6-bit coding on M9)
Message from Frank.Dernie at (Frank Dernie) ([Leica] CV Ultra-wide Heliar (12mm) 6-bit coding on M9)