[Leica] 6-bit codes -- Don't Bother

[leicaluvr at comcast.net (Tom Schofield)]

Sound's about as important as ROM coding on R8/9.

I was wondering how this would work without aperture data as well as  
focal length, because  vignetting varies with stopping down as well  
as the particular lens in use.  Maybe its just an averaged  
approximation rather than a precise cancellation.

And I was looking forward to Noctilux shots without Vignetting!

Tom Schofield


On Oct 7, 2006, at 10:05 PM, David Keenan wrote:

> I determined from looking at images projected during the Leica  
> Akademie in
> Wetzlar last week that the 6-bit coding business is primary a  
> marketing
> gimmick.
>
> The only realistic reason evident was to have the lens focal length  
> included
> in the image file EXIF data.
>
> There were many images taken by average joes with a variety of  
> lenses with
> no visible vignetting.
>
> I even took some with the VC 12mm lens that at least on quick  
> review showed
> little or no vignetting.
>
> The 6-bit code does not distinguish between, for example, which of  
> the three
> focal lengths a Tri-Elmar may be set to, so what processing can the  
> camera
> actually do? None. It cannot apply the same vignetting or other  
> algorithm at
> 28mm, 35mm, and 50mm.
>
> Furthermore, it's not clear at this point that different versions  
> of the
> same Leica lens at a given focal length will have a different code  
> -- so a
> new 28mm lens may have the same code as a 1950s version. So, again,  
> there is
> no practical optical correction that the camera's processor can apply.
>
> And no one from Leica indicated that this coding was essential. All  
> the
> cameras we had that day had the 6-bit code detection feature turned  
> off.
>
> So, buyer beware.
>
> Dave.
>
> -- 
> My Photography: http://www.david-keenan.com
> My Blog: http://www.david-keenan.com/euroblog
>
> _______________________________________________
> Leica Users Group.
> See http://leica-users.org/mailman/listinfo/lug for more information