Archived posting to the Leica Users Group, 2011/12/29

[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]

Subject: [Leica] M9 DNG compression
From: kanner at acm.org (Herbert Kanner)
Date: Thu, 29 Dec 2011 22:09:07 -0800
References: <p06240807cb227842f4d7@192.168.1.101> <002a01ccc66a$2e0738c0$8a15aa40$@chiaroscuro.co.nz> <0575E4AC-D5E1-4B15-BDE6-6E33E3DE6C50@archiphoto.com> <CAF8hL-FHkeLQb-sxzGA=6VHPTkW+i7Qt=1EtnPi8t8UrgEiM6Q@mail.gmail.com> <002b01ccc683$7c2b2700$74817500$@chiaroscuro.co.nz>

See the link in John McMaster's post. It's clear that Leica's 
compression requires trivial processing. Lossless LZW or whatever 
would take much too much processing.

Herb


>Not sure if it is a processing limitation or if a firmware update can make
>it lossless like the S2....
>
>john
>
>-----Original Message-----
>
>
>I also shoot compressed because of the write speed. I use 16 GB cards so
>storage is hardly ever an issue.
>
>Here's a thread on the actual algorithm used, which I found somewhat
>surprising.
>http://www.l-camera-forum.com/leica-forum/leica-m9-forum/206098-dng-compress
>ion-any-difference-quality-2.html
>
>  I guess normal LZW / zip type of compression takes too much processing
>time. Come to think of it, I'm surprised that no one in the camera industry
>has designed a "compression" FPGA chip....
>
>On Thu, Dec 29, 2011 at 1:53 PM, Henning Wulff
><henningw at archiphoto.com>wrote:
>
>  > I too have never seen a difference to date. Early on I shot a number
>  > of comparisons to make sure I wasn't doing something stoopid, but as a
>  > result of those tests and information from Leica I now shoot
>  > compressed. It's not a matter of disk space or card space, but of
>  > speed. The buffer in the M9 is small enough, and clears slowly enough
>  > that any speed enhancement is noticeable, and there is a BIG
>  > difference in the speed. Try shooting a buffer full of compressed vs.
>  > non-compressed images and see how long it takes for the buffer to clear
>(write light to stop blinking).
>  >
>  > I don't shoot in continuous mode, but I do expect the camera to be
>  > ready when the shot arrives in the viewfinder. When the buffer is
>  > full, the shot is often gone by the time the camera is ready again.
>  >
>  > Henning
>  >
>  >
>  > On 2011-12-29, at 12:41 PM, John McMaster wrote:
>  >
>  > > I don't think any real difference has been seen at this stage. The
>  > > main thing is whether future software can bring more information out
>  > > of a DNG file which may be lost if compressed. I shoot uncompressed
>  > > and deal with
>  > the
>  > > data ;-)
>  > >
>  > > john
>  > >
>  > > -----Original Message-----
>  > >
>  > >
>  > > Has anyone ever done a comparison of the 34.6 Mb Leica DNGs to the
>  > > compressed versions which are 18 Mb more or less depending on the
>  > > degree
>  > of
>  > > detail in the image? While it is not an issue for me, with a mere
>  > > 1000 to
>  > > 2000 images per year, terabyte drives being so cheap, It probably is
>  > > an issue to the much more prolific professional photographers.
>  > >
>  > > The question is: has anyone ever found an image where this degree of
>  > > compression has been seen to matter?
>  > >
>  > > Herb
>  > >
>
>
>
>_______________________________________________
>Leica Users Group.
>See http://leica-users.org/mailman/listinfo/lug for more information

-- 
Herbert Kanner
kanner at acm.org
650-326-8204

Question authority and the authorities will question you.


Replies: Reply from john at mcmaster.co.nz (John McMaster) ([Leica] M9 DNG compression)
In reply to: Message from john at chiaroscuro.co.nz (John McMaster) ([Leica] M9 DNG compression)
Message from henningw at archiphoto.com (Henning Wulff) ([Leica] M9 DNG compression)
Message from richard at richardmanphoto.com (Richard Man) ([Leica] M9 DNG compression)
Message from john at chiaroscuro.co.nz (John McMaster) ([Leica] M9 DNG compression)