[Leica] M9 DNG compression

[richard at richardmanphoto.com (Richard Man)]

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-compression-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
> >
>
>
> Henning Wulff
> henningw at archiphoto.com
>
>
>
>
>
> _______________________________________________
> Leica Users Group.
> See http://leica-users.org/mailman/listinfo/lug for more information
>



-- 
// richard <http://www.richardmanphoto.com>