Archived posting to the Leica Users Group, 2007/01/10

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Subject: [Leica] M8 Article in LFI
From: faneuil at gmail.com (Eric Korenman)
Date: Wed Jan 10 19:09:00 2007
References: <82c9dd70701100344o846c0b2q260df0f3ae6aaa4b@mail.gmail.com> <20070110122016.E0F792FCA5@donald.hostspirit.ch> <000a01c73511$f3ddbd20$6501a8c0@asus930> <82c9dd70701101605g3f4a6df8sb6c2901cdfb8e5bd@mail.gmail.com> <32232.203.48.242.245.1168484363.squirrel@webmail.ncable.net.au>
 
right - That was my point from an earlier post.
The M8's 8 bit DNGs are derived by compressing the 14 bit CCD data.

But does the M8's 'square root' compression technique sacrifice image
quality?
The LFI article would have you believe that there is no loss.
However the technique is inherently lossy.

Any science / math types out there care to chime in?


Eric

On 1/10/07, Alastair Firkin <firkin@ncable.net.au> wrote:

> > The DMR chip captures 14 bit directly into 16 bit DNG files.
> > Thats why DMR RAW filres are 20mb
> > And the 8 bit DNGs from the M8 are 10mb
>
> I do not believe so: the saving in space is done in the "compression" of
> the RAW file: the bit depth of the DMR and M8 are the same
>
> Cheers
>
>
> _______________________________________________
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Replies: Reply from imagist3 at mac.com (Lottermoser George) ([Leica] M8 Article in LFI)
 In reply to: Message from faneuil at gmail.com (Eric Korenman) ([Leica] M8 Article in LFI)
Message from leica at screengang.com (Didier Ludwig) ([Leica] M8 Article in LFI)
Message from hoppyman at bigpond.net.au (G Hopkinson) ([Leica] M8 Article in LFI)
Message from faneuil at gmail.com (Eric Korenman) ([Leica] M8 Article in LFI)
Message from firkin at ncable.net.au (Alastair Firkin) ([Leica] M8 Article in LFI)