Archived posting to the Leica Users Group, 2007/05/08

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Subject: [Leica] Lenses without 6 bit code in M8
From: kididdoc at cox.net (Steve Barbour)
Date: Tue May 8 08:28:25 2007
References: <463EA499.6020703@dlridings.se><14314517-2EB5-4852-929D-527C786B9EE5@pandora.be><46401505.4060705@dlridings.se><00f701c7913e$9d83aa00$7605a8c0@VAIO01> <82c9dd70705080347w2664eb3btffa8eb0a8fdc248d@mail.gmail.com> <003701c79172$90ca8840$7605a8c0@VAIO01> <E3AAD61B-0B74-456B-9478-138C41613828@comcast.net>

this is beautifully explained by Leonard,  much better than I could  
do...

though as I went through it...Leica's fixes and counter fixes seem  
absurd in the extreme...

Let me say...I use an M8...I use latest firmware, widest lens 21mm,  
no filters, no lens coding...have had no problems.

I shoot mainly bw, though when I do shoot color I have no problems,  
unless I create them... and I must say I have been even more  
impressed by the color  than the bw results...

The unexpected outcome has been, that the M8 has led me to shoot more  
color rather than trying to avoid it.


Steve


On May 8, 2007, at 7:00 AM, Leonard Taupier wrote:

> Claudio,
>
> Originally when Leica announced the 6 bit coding it was to identify  
> the lens and optimize it's performance. Probably to correct for  
> vignetting.
>
> Then it was discovered that the Leica image sensor had a reduced  
> infra red filter which caused certain dark materials like polyester  
> cloth, leather and even natural colors of flowers to turn toward a  
> strong magenta color.
>
> In order to eliminate the magenta caused by the strong IR, Leica  
> suggested using a special IR/UV filter to remove the IR and correct  
> the off color cast. This is fine but the filter causes the edges  
> and the corners of the photo to turn a cyan color. This problem is  
> increased as the angle of the light increases through the filter.  
> The widest angle lenses are the worst and the condition improves as  
> the angle decreases in the lesser angled lenses.
>
> Leica found they could correct for this cyan color cast by  
> compensating the color of the affected edges of the photo. Since  
> the amount of compensation is different for the different lenses,  
> the camera has to know what lens is being used when the special  
> filter is installed. The way to do this is to code the lenses.
>
> Regards,
> Len
>
>
> On May 8, 2007, at 9:12 AM, Dott. Ing. Claudio Rimediotti wrote:
>
>> Thanks!
>> And now another question:
>> the reason why of this 6-bit code?
>>
>> Thanks again,
>>
>> Claudio
>>
>> ----- Original Message ----- From: "Eric Korenman"  
>> <faneuil@gmail.com>
>> To: "Leica Users Group" <lug@leica-users.org>
>> Sent: Tuesday, May 08, 2007 12:47 PM
>> Subject: Re: [Leica] Lenses without 6 bit code in M8
>>
>>
>>> short answer: none!
>>>
>>> Eric
>>>
>>>
>>> On 5/8/07, Dott. Ing. Claudio Rimediotti  
>>> <studio.rimediotti@iol.it> wrote:
>>>>
>>>> I'd like to know what are the problem to use old Leica lens  
>>>> without 6 bit
>>>> code in an M8.
>>>>
>>>> Thanks, regards from Italy!
>>>>
>>>> Claudio Rimediotti
>>>>
>>>>
>>>> _______________________________________________
>>>> Leica Users Group.
>>>> See http://leica-users.org/mailman/listinfo/lug for more  
>>>> information
>>>>
>>>
>>> _______________________________________________
>>> Leica Users Group.
>>> See http://leica-users.org/mailman/listinfo/lug for more information
>>
>>
>> _______________________________________________
>> Leica Users Group.
>> See http://leica-users.org/mailman/listinfo/lug for more information
>
>
> _______________________________________________
> Leica Users Group.
> See http://leica-users.org/mailman/listinfo/lug for more information


Replies: Reply from len-1 at comcast.net (Leonard Taupier) ([Leica] Lenses without 6 bit code in M8)
Reply from mark at rabinergroup.com (Mark Rabiner) ([Leica] Lenses without 6 bit code in M8)
In reply to: Message from dlr at dlridings.se (Daniel Ridings) ([Leica] IMG: PAW 18 dlridings)
Message from philippe.orlent at pandora.be (Philippe Orlent) ([Leica] IMG: PAW 18 dlridings)
Message from dlr at dlridings.se (Daniel Ridings) ([Leica] IMG: PAW 18 dlridings)
Message from studio.rimediotti at iol.it (Dott. Ing. Claudio Rimediotti) ([Leica] Lenses without 6 bit code in M8)
Message from faneuil at gmail.com (Eric Korenman) ([Leica] Lenses without 6 bit code in M8)
Message from studio.rimediotti at iol.it (Dott. Ing. Claudio Rimediotti) ([Leica] Lenses without 6 bit code in M8)
Message from len-1 at comcast.net (Leonard Taupier) ([Leica] Lenses without 6 bit code in M8)