[Leica] 6-bit code as installed by Leica

[hoppyman at bigpond.net.au (G Hopkinson)]

Steve, Leica has stated on-line that the 6 bit code adds some info to the 
exif data, some control functions for compliant flashes
(and tht might only mean recognise the focal length), and some vignette 
reduction in the firmware. We know that there is also
adjustment for that vignetting via the micro-lenses positioning over the 
sensor. That doesn't tell us whether the exif data is lens
model specific or just focal length specific nor whether the additional anti 
vignetting is applicable to which or all lenses. I'd
suggest that it needn't be required or significant for all. Looking at the 
dng that was part of a review posted here recently, and
the other examples so kindly shared, I see only ISO, shutter speed and focal 
length recorded
Cheers
Hoppy


-----Original Message-----
From: lug-bounces+hoppyman=bigpond.net.au@leica-users.org 
[mailto:lug-bounces+hoppyman=bigpond.net.au@leica-users.org] On Behalf Of
Steve Barbour
Sent: Monday, 30 October 2006 07:14
To: Leica Users Group
Subject: Re: [Leica] 6-bit code as installed by Leica


On Oct 29, 2006, at 9:20 AM, Dave Mason wrote:

>
> I am certainly not claiming that they are deceitful - or that the
> person who posted info earlier is - I just don't understand it. I
> would take the 6 bit/64 lenses idea if one of the lenses that they
> won't put the coding on wasn't an earlier (e.g., mid-1980s) Summicron
> 50. In terms of Exif data a "Summicron 50mm f/2.0" is a "Summicron
> 50mm f/2.0" is a "Summicron 50mm f/2.0".... isn't it?


  I have heard speculation that the coding might aid software  
correction for various lenses... don't know if this is true... but  
Leica ought to be clear about what it does and what it might  
eventually do...Steve


>
>
> Dave
>
> Brian Reid <reid@mejac.palo-alto.ca.us> writes:
>
>>> I'm just curious why Leica claims not
>>> to be able to put the coding on older lenses if its just to put a  
>>> text
>>> string in the EXIF data. It doesn't make any sense.
>>
>> I start with the assumption that Leica is not being deceitful.
>> You can call them a lot of things, but manipulative and deceitful  
>> is not one of them.
>> I have to assume that they have a reason to do this.
>>
>> Here's what I think. A 6-bit code can identify no more than 64  
>> different lenses. I'd be willing to bed that since the release of  
>> the M3 50 years ago, Leica has issued maybe 50 different kinds of  
>> lenses. If they were willing to put 6-bit codes on all of them,  
>> they'd only have room for a dozen new lenses and then the code  
>> would be full.
>>
>> So I think if I were them, I'd pick about 20 to 30 of the more  
>> modern lenses and assign them code numbers, and reserve the  
>> remaining 30 to 40 numbers for products that they haven't shipped  
>> yet.
>>