FW: [Leica] M8 Article in LFI

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

Eric, I managed to locate the rather gargantuan thread on this subject in 
the Leica User Forum. My brain hurts. If you are feeling
especially robust, here it is.
http://www.leica-camera-user.com/digital-forum/7498-m8-why-10mb-vs-dmr-20mb.html
The executive summary, as near as I can figure is that the difference 
between the DMR & M8 file size is due to the use of lossless
compression with the M8. The issue of how the final M8 file is arrived at is 
rather more painful.
The empirical result from the couple of original DNGs that I have is that 
the file saves as a 16 bit TIFF of about 59MB. When the
tonal range is manipulated in Photoshop it shows none of the posterisation 
and gapped histogram that I would expect when performing
the same operation on an 8 bit file, such as a JPG.
I want one.
Cheers
Hoppy


-----Original Message-----
From: G Hopkinson [mailto:hoppyman@bigpond.net.au] 
Sent: Thursday, 11 January 2007 10:45
To: 'Leica Users Group'
Subject: RE: [Leica] M8 Article in LFI

Thanks Eric, I have no experience at all with the DMR, except admiring 
magnificent output from Doug Herr, for example. My
understanding is that both sensors are capturing at 14 bit. It's what's 
happening afterwards that I am most interested in. 14 bit to
a 16 bit DNG must involve processing too. The sample M8 DNG that I have here 
saves as a 59MB 16 bit TIFF.
Do you think that the file size difference could be due to more efficient 
lossless compression with the M8? I have an idea that this
subject has been attacked within the Leica User Forum. I must do some 
searching.

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
Eric Korenman
Sent: Thursday, 11 January 2007 10:06
To: Leica Users Group
Subject: Re: [Leica] M8 Article in LFI

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 think the upper end Canon's chips capture 12bits of data.
I am sure a Canon user will chime in here.

Eric


On 1/10/07, G Hopkinson <hoppyman@bigpond.net.au> wrote:
>
> Guys this is an area of great interest to me. I do wish that I had that
> LFI article. AFAIK no digital camera sensor captures at a
> higher bit rate than that. There's a lot that I don't understand regarding
> that processing within the camera. However empirically,
> when you manipulate the M8 RAW files tonal range within Photoshop they ARE
> emphatically superior to any 8 bit file and certainly as
> robust as any 16 bit scan from 35mm (which is my own experience).
> So I join Eric in hoping that a LUG member of scientific bent can give us
> an insight into the in-camera processing.
>
> 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
> Didier Ludwig
> Sent: Wednesday, 10 January 2007 22:21
> To: Leica Users Group
> Subject: Re: [Leica] M8 Article in LFI
>
>
> >So.. Isn't the weakest link in the imaging processing chain an 8 bit
> format?
>
> yes if you exclude 6-bit and 4-bit format
>
> >LFI then goes on to say essentially "you won't see the difference anyway"
>
> This translates in "the main thing is there's a red dot on"
> ;-)
> Didier
>
>
>
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