The "Zone System", as specified, is merely the chemical equivalent of
PhotoSlop's curve tool.  But PhotoSlop is a hell of a lot simpler
though, in that you don't have to calibrate your media and development
and the whole rest of the stuff:  that's all been done for you by
Canon.  "Expose to the right" is utterly identical to "expose for the
shadows, develop for the highlights":  the laws of physics didn't
suddenly change when digital cameras were invented.

This is well written and well thought out.
Digital capture and processing are far more flexible than chemical systems
even if digital sensors as yet lack the dynamic range of negative film. As
such most serious photographers develop a workflow that maximizes what they
are trying to capture and print. The impact of software processing of
digitized image information is such that the ways photographers think about
their tools needs to change.
Nevertheless the standard canard still applies that all serious
photographers should familiarize themselves with the Zone system because it
emphasizes thinking about lighting values in relation to the actual capture
properties of the medium.
Clearly the Zone system lends itself to static subjects and not every image
can be analyzed in the required way prior to capture.
The Zone system is essentially predicated on the idea that you want to
produce one type of image, the long tone black and white print. The
principles of the Zone system, aimed at capturing as much image information
as possible, clearly have a place even in the brave new digital world
although the long tone black and white print is not a major endpoint for
most photographers.
Photoshop and the ACR are not a rigid either/or proposition. There is
nothing sacred about making adjustments within the converter or within
Photoshop. Also the newest CS3 converter is far more flexible than the first
generation CS converter. The conversion from digital color to black and
white introduces many tonal variables independent of pure exposure issues.
Again CS3 contains new tools for accomplishing this.

1. The zone is B&W negative exposure, development and print oriented.
2. Slide film is different (exp. for the highlights).
3. Digital, for the most part, behaves like slide in this respect

I'll give your webpage a good read, but I suspect for practical purposes
that setting the highlights near the right edge of the histogram is as
optimal as it will get unless I'm willing (and I am) to burn some
highlights to get details in other areas of the image.

Cheers,
Alan.

I think you might want to look at some of the numbers you are using, I
get far more then a rangle of 50 to1 with jpeg images and I don't
believe you can get close to 500 to 1 printing on any kind of paper.

As for setting the proper exposure it is a pretty rare scene where when
I expose to keep from blowing out the highlights I loose the shadow
detail.

Scott

Hi Gisle,

I'm reading your paper at present. Most of it I like but a couple of
points I think are wrong:
1. In section 2, Background, you say that both the dynamic range and
tonal range are a function of the number of bits available. This seems
only partly true. The dynamic range of a digital sensor is determined by
its charge capacity (ie how full it can get before saturating or
overflowing into adjacent pixels (blooming)), linearity of photon to
electron conversion efficiency, any electronic gain circuitry,
characteristics of the A/D converter, etc. Number of bits determines how
finely you can resolve differences within this range, not the size of
the range itself.
2. In section 4, you confuse incident metering with reflected light
metering, as the way cameras meter. Incident metering uses a handheld
light meter with one of those white domes (not necessarily, but
commonly) to measure the light that is actually incident to, ie hitting,
the subject. Reflected light metering is what cameras use, since they
read the light reflected from a scene, hence their tendency to make a
black cat in a coal pile look like middle gray.

Cheers,

Wayne

...

I like your writing style well enough, and the layout is good.
(You need to go over it with a spell checker.  When I spell
checked this article almost half the mistakes were in the quoted
text!  Given that I can't spell, your spelling must not be too
good either!)

A few points came up while reading.

 Limitations
 ...

 It is obvious that with JPEG, which uses 8 bits per channel,
 the dynamic range cannot exceed 1:256 (i.e. 8 EV).

That would be true if and only if JPEG was using linear data,
but it is gamma corrected.  JPEG can have at least an 8 f/stop
dynamic range.  That is a "useful dynamic range", which is
generally confined to the range that allows at least 8
brightness values in the lowest f/stop of the range.  (If we
looked at it the way some people do the dynamic range of film,
it would be more like 14 f/stops, but in the darkest level there
would only be two levels and that generally would result in very
unattractive posterization if actually used.)

 Doing it Digital -- First Approach

   With digital, we can no longer play around with
   development times.  ...

We can do *exactly* the same thing that happens when we play
around with development times.  Just change the ISO setting on
the camera!

 The Troublesome Highlights

   With digital, highlights are a real problem. First,
   we never want overexposed highlights - not even in
   a single colour channel.

   Unlike film, which has great exposure latitude at
   the highlight end, digital is very unforgiving in
   the case of overexposure. Detail that is lost
   through overexposure, is clipped and lost
   forever. So why should we not place shadow detail
   in the lowest possible Zone ? that should in most
   cases contain our highlights well within safe
   limits?

I realize that is the standard mantra, but it is a sugar
coated version of truth.  Detail lost with over exposing
film is also lost forever.  The fact is that pushing highlights
up into the toe of the film's range will lose texture too,
and just isn't the right way to make good photographs.

The difference is that after you improperly expose film, you
still have the option of changing development (to essentially
change the ISO rating), where as with a digital camera you can't
do that.  Of course, with a digital camera you are 1) much more
likely to have the tools built into the camera to determine that
it is in fact over exposed, and 2) you have the option of
adjusting the ISO setting and immediately making another
exposure to get the same effect that film would give, or 3)
changing the shutter or aperture settings and making another
exposure.

Obviously if the scene is a one time only, film has the
advantage.  But for any scene existing long enough to take
multiple images, digital is more likely to result in a
valid results.

   ...  Both articles argue that in a 12-bit
   linear RAW file, 2048 levels (half the 4096 values
   allowed) will be use to record the f-stop with the
   brightest tones. It follows that if the values
   allocted for the brightest tones in the scene are
   wasted (i.e. your brightest highlights are -1 EV
   down the tonal scale), you are wasting half the
   luminance encoding levels your camera is able to
   record.

The emphasis on "wasting half the luminance encoding levels" is
poorly placed.  It is a simple fact that in *most* images nearly
all (1979 of the 2048) can be deleted without any visible
change!  (I.e., JPEG uses only 69 levels for that same f/stop.)

It sounds good, but doesn't mean much.  Nikon's NEF format can
be used with and without compression, and with compression what
they do is remove a significant number of brightness levels from
the top three f/stops.  For most images it has virtually no
effect.  Only for high key images where the texture of
highlights is important does it have an effect (for example,
wedding photography).

   Reichmann's recommendation, reflected in the title
   of the article, is that you should use your cameras
   histogram to evalute the light in the scene, and
   push exposure towards overexposure so that the
   histogram moves as far as possible to the right
   edge (without moving so far that highlights are
   blown as indicated by your camera's clipping
   warning). Doing so, Reichmann says, will improve
   the signal-to-noise ratio and therefore produce
   less noise and banding in the darker areas.

The effect is, as others have stated... just about exactly the
same as using the zone system with film.  The difference is that
you do both exposure and development at the click of the shutter
release with digital, and don't make adjustment between those
steps.  That is to say the ISO setting is done before the
shutter release with digital, but can be adjusted afterwards
with film.  In either case contrast and the black point are set
in the process of printing (or display).

The real difference is that with a digital camera we probably
have a histogram and maybe a blink-on-overexposure display to
help determine if the exposure is correct.  Histograms are nice,
but a blink-on-overexposure display is essential if there are
light sources, or other highlights that are to allowed to be
over exposed, in the scene.

With film the same effect is accomplished by using a spotmeter.
It requires an eye for scenes and light, knowing corrects for
various lenses or accessories (bellows, extension tubes, etc) as
well as the ability to provide uniform development of the film,
based on the desired effects, every time.  These skills are what
makes a film photographer consistent.  (Part of the reason many
film photographers enjoy using film is simply that it *does*
require certain skills, and because they have honed those
skills it is certainly fun to use them!  And more or less
natural to dismiss digital as photography that doesn't require
skills...)

There's a Photoshop plugin that already does this automatically - it's
called Ozone (current version is 2.0):

http://www.pluginz.com/product/10254?from=rlist