Digital BW, The Print

As a point of clarification, I believe what concerns the user most is the
usable dynamic range delivered by the camera - not the dynamic range of the
sensor ignoring all other aspects.  I have always found it puzzling that
Canon has not moved to delivering the user 16 bits and had always assumed
that the issue was processing speed.  Many (most?) Canon 35mm users are
concerned about speed, at least much more so that someone using a digital
back, and hence this is an important consideration for Canon as they design
their cameras.  So, given their optical system/format, they have a
constraint on sensor size, from which they manage a set of tradeoffs
including "resolution", pixel size, noise and processing speed to name just
a few.  The question that concerns my original post is whether or not, all
else being equal, an increase in bit depth provides greater usable dynamic
range to the user.


> From: Steve Kale <stevekale@...>
> Reply-To: <DigitalBlackandWhiteThePrint@yahoogroups.com>
> Date: Sun, 03 Jul 2005 12:49:33 +0100
> To: <DigitalBlackandWhiteThePrint@yahoogroups.com>
> Subject: Re: [Digital BW] Artifacts with Digital images
> 
> Jeff 
> 
> Thanks for this.  I am interested in hearing a more direct retort to the
> material on Normen's site (I have previously posted the link).  As I read
> it, he is quite clear that a greater bit depth provides greater dynamic
> range (measured in f-stops or whatever).  He notes, as you do, that noise
> affects the "bottom end" of the range and that noise is highly correlated to
> pixel size.  (It goes without saying that we would all prefer more larger
> pixels, appropriately cooled of course, but digital camera/digital back
> design is constrained by both economics and the need to fit current lens
> format dynamics.)  But I hear you saying that for a given noise level and
> given pixel size, more bit depth makes no difference.  Can you expand on
> this a little and if possible correct the information, or my understanding
> of the information, on Normen's site.  I suspect the "line of difference"
> (so-to-speak) lies somewhere in his assumption "that the darkest useable
> zone has 8 levels" and that the number of useable levels is affected by bit
> depth, ie he is talking about the limitations imposed by engineering
> decisions which affect things post photon capture: that once one have
> determined the "size of the well" the ultimately delivered dynamic range is
> still affected by bit depth whereas you would say this is not true and that
> increasing bit depth is of no value.
> 
> Thanks
> 
> Steve