[Leica] New M(246) Outputs 12 bit Files

[Peter Klein]

 This is been discussed extensively on the LUF. A  gentlemen
dubbed "lenshacker" has discussed how he sees pattern noise in M246 files,
but sees only random noise in the MM files.  He's someone with extensive
experience in digital signal processing.  What he saying is that the
stripping off two bits of real information causes the noise to get less
random, to go from not there to there in such a way that patterns start to
emerge.   Faint bands as opposed to random quote peppering" of noise. It
sounds a lot like Schrodinger's cat, but you can see it if you pixel peep.
How much it will matter  in real photographs, I don't know.

 As to why Leica made this choice, who knows? It might be a matter of
acceptably fast processing speed, or that the imaging hardware can't handle
the extra bits meaningfully.

 But I remember what Leica said about the M8 compressed DNG files.   They
said that nobody could tell the difference between the compressed
vs. uncompressed files. But now we've discovered the way to make the M8
output uncompressed raw files, and the truth is more complicated.   The
compression doesn't matter in well-lit scenes where you're not going to
tweak the curves too far. But in low-light files it matters a lot.  I've
seen the difference with my own eyes in my own photographs. So I wouldn't
discount this argument as one of those mythical medieval discussions about
the number of angels that can dance on the head of a pin.

-- Peter, picking a peck of peppered pixels


On Tuesday, May 5, 2015, Richard Man <richard at richardmanphoto.com> wrote:

> Jim, re: write speed
> 12 bits is a bit PITA to carry around. Usually 16 bits is used and the
> software just ignores the 4 unused bits.
>
> On Tue, May 5, 2015 at 8:10 PM, Jim Nichols <jhnichols at lighttube.net
> <javascript:;>> wrote:
>
> > Wouldn't it also affect write speeds?  What if Leica puts more value on
> > speed than on bit depths?
> >
> > Jim Nichols
> > Tullahoma, TN USA
> >
> > On 5/5/2015 10:04 PM, Doug Herr wrote:
> >
> >> Sometimes the published bit depth has more to do with marketing than
> >> anything else.
> >>
> >> Doug Herr
> >> Birdman of Sacramento
> >> http://www.wildlightphoto.com
> >> http://doug-herr.fineartamerica.com
> >>
> >>
> >> -----Original Message-----
> >>
> >>> From: Richard Man <richard at richardmanphoto.com <javascript:;>>
> >>> Sent: May 5, 2015 6:01 PM
> >>> To: Leica Users Group <lug at leica-users.org <javascript:;>>
> >>> Subject: Re: [Leica] New M(246) Outputs 12 bit Files
> >>>
> >>> The "bit-depth" is not dependent on the format. If 12 bits is good
> enough
> >>> for 35mm sensor, then it would be good enough for medium format sensor,
> >>> and
> >>> vice versa.
> >>>
> >>> Note that I have not said what I think personally on the technical
> >>> merits.
> >>> I am just giving out the perspective that the decision is almost
> >>> certainly
> >>> financial related rather than based on technical analysis.
>
>