Why No 'Expose to the Right' Mode?

From time to time on the Internet, including several times in the comments to Ctein's post yesterday, I hear people wish that digital SLRs had an automatic "expose to the right" mode that would put the histogram right up to the right edge, meaning no highlight pixel would be saturated and the maximum value would be achieved for all the rest. Theoretically, for any given scene—even those that exceeded the dynamic range of your sensor—this would give you the most to work with in software, maximizing shadow detail and contrast and minimizing noise.

Sounds good, right? For many scenes it would be. Maybe it would even be useful, overall.

The reason it wouldn't work all the time is that there are plenty of occasions when you want your highlights to overexpose. In the kind of shooting I do, I encounter them often: A dusk scene sprinkled with pinpoint streetlights and house lights; a lonely winding road with a single car's headlights coming at you in the middle distance; backlit bright afternoon summer sunlight sparking on windswept water.

These are examples of the many scenes that have in them what are called "specular highlights," a generalized way of referring to accent highlights that are off the scale—the kind that in traditional black-and-white photography would be purposefully rendered as "paper white." If a camera's meter could detect these and put them within the scale of recordable values (tones)—"expose them to the right"—then the rest of the exposure might be so far wrong as to not be salvageable. The most common example is probably just the sun in the picture, assuming your lens is good enough not to flare out.

(Ansel Adams once performed an unusual virtuoso trick with the sun. Utilizing partial solarization, a peculiar property of film whereby extreme excess exposure not only triggers a failure of the reciprocity law but also results in less negative density, he created a picture (in Portfolio V, 1970) called "The Black Sun, Tungsten Hills, California," in which the disk of the sun is rendered near-black and the rest of the picture is exposed normally and not solarized. I suppose that's not really pertinent here, but it's a nice anecdote. Incidentally, Portfolio V was the first of Adams's portfolios he printed large, on 16x20 paper, and for which he used older negatives, and he committed to never printing any of those negatives again. Despite this limitation, few of them are now among the most valuable Adamses.)

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A picture of Adams you've never seen before: Ansel Adams, Photo Booth Self-Portrait, c. 1930, from the collection of the Archives of American Art, in the Katherine Kuh papers. If he could have obtained the negative from the machine, he probably would have tried to print it better!

-

Last night I snapped the "record shot" shown above of our house all dolled up for Halloween (handheld at 1/5th of a second and dead sharp, O ye who doubt the usefulness of IS—but I digress. Again). In this shot, would you really want the camera to "place" the luminances of the electric pumpkin next to the steps "to the right," so that none of its pixels were saturated? If it had, I would have lost an unacceptable amount of shadow information off the left side of the histogram—much more than I actually already did lose. The picture would have been useless. There are many such situations in real-life shooting that would require operator intervention if such a feature existed. There's a reason why "averaging" metering is so effective.

Incidentally—I digress yet again—we had a nice Halloween, with about 250 trick-or-treaters. Generally, we have an exceptionally attractive cohort of rug rats in these precincts, and the little chuppers are very polite. For a while I had to stand out front, because a fair percentage of four- and five-year-olds find our house sufficiently scary that they won't come up to the door. The strangest things I saw were a) a teenager elaborately dressed as a toilet, and b) three middle-aged Hispanic women dressed in black plastic bags over their clothing actually asking for candy. I don't know—recent immigrants who aren't quite clued in to the subtleties of the holiday yet? Beats me. Apart from such anomalies it was a very social evening, a chance to see neighbors seldom seen, with family bands roaming up and down the streets and lots of animated conversation.

But back to our topic. Cameras do an awful lot for us these days—including, now, providing a near-instant "Polaroid" so you can check your composition and focus, and (on some cameras) tricolor histograms so you can check exposure in every color channel. Sci-fi stuff by the standards of, say, Ansel's lifetime. But no matter how much our cameras do for us, there's never—I mean never—going to be a mechanical-electronic means of getting every exposure just the way you want it, if only because "perfect exposure" is forever going to be partially a matter of taste and individual intention, at least occasionally. For better or for worse, the best way of creating the best exposure includes the application of  of experience and judgment as well as the use of the measurement device between your ears along with all your other measurement devices...however sophisticated the latter might be.

____________________

Mike

Featured Comment by Thom Hogan: Obviously, 'it wouldn't work all the time.' Current metering systems don't 'work all the time' either.

But would Mike object to an Ansel Adams Zone System spot meter that gave you a precise indication of where other values were if you were to assign one reading as Zone X or I? Somehow, I think not.

Because this is a highly visible site, I worry about seemingly outright rejection of an idea, as it often causes the camera makers to reject more than the basic idea. Let me see if I can explain.

One problem with digital is that it is indeed linear and so much of the lower half of tonal range is recorded in so few bits. Besides meaning less capable tone ramps, it also means a lower signal-to-noise ratio for the low exposure zones.

The other problem is this: we don't know what our cameras are telling us. That's particularly true if you shoot raw, as the histogram and highlights display isn't based upon the actual data, but an interpretation of the data (the embedded JPEG, demosaiced with the camera settings). Worse still, not a single manufacturer that I know of has revealed at what point their highlights display triggers. Essentially, the camera makers are assuming we're not very smart and they're trying to protect us from ourselves.

We really need several bits of information:

1. How much of the scene has photosite saturation (well overflow) in it.

2. Where that saturation lives in the scene.

3. What channel(s) that saturation lives in.

4. How much of the scene has photosite underutilization*.

5. Where that underutilization lives in the scene.

6. What channel(s) that underutilization lives in.

7. What the underutilization assumption is (and this is one that should be user changeable; some people have more aversion to noise than others).

8. Histograms on well data in the range between saturation and underutilization.

*We don't have a good name for this. I use underutilization as meaning the point at which the SN ratio drops below a certain point, essentially defining the point where pulling out additional detail is impossible to distinguish.

If Mike had all that information, he'd actually be more capable of interpreting whether the blowout his camera is telling him he has is really what he wants and whether the rest of the exposure is working. But we're not likely to get that information if camera makers think that anything relating to expose-to-the-right (ETTR) is going to be rejected by a significant portion of the shooting public.

In the picture he shows as an example, we've got a lot of the frame rendered essentially with no detail. He very well may want it to be that way (after all, Halloween is supposed to be spooky, and low/no detail is supportive of spooky), but let's say there was a face in one of the windows. Does he have it in his exposure in a way that he can work with it in post processing? You wouldn't know with the current camera exposure helpers. And, yes, an Auto ETTR would worsen that problem. More on that in a moment.

The point is that most of us who talk about anything related to ETTR really are asking for more, and more accurate, information about the exposure. Since in digital we can review the exposure immediately, it makes large sense to make sure that the information we have is optimal in that respect. It currently isn't.

The idea of an automatic expose to the right exposure mode is akin to Program exposure mode or (ahem) Scene exposure modes. It would thus obviously be targeted at novices who don't know what they're doing or don't want to think about anything more than where to point the camera (and quite frankly, it would need an automatic post processing companion to bring the exposure back to visually appealing).

Mike is right in that every time we cede control to an automatic control, we give up some of the decision-making that is integral to optimizing the making of a photograph. Sometimes we do that because we're not sure we can make those decisions fast enough (autofocus comes to mind), but most pros think seriously about as many of those decisions as they can for every picture they take.

Still, right now we have to guess as the accuracy of the information we're being given to evaluate our decision-making. I'd rather not guess. Give me the right data, presented correctly. If that means that we also get an Auto ETTR mode that I'll never use but might work for someone else, that's fine with me. I can ignore those (ahem) Scene exposure modes as long as I have P/A/S/M, for example, and ETTR is something along those lines: I can ignore Auto ETTR as long as I have the info that underlies it so that I can manually control it.

So let's not try to talk the camera makers out of exploring ETTR. Let's instead convince them that there are consumer and pro aspects of ETTR and we both want an optimal set of controls for it.

______________________

Thom

Comments

[Dave]

I raised the very same question in May of 2006 on the Luminous-Landscape forums and the discussion went on for 5 pages and into areas of math way beyond me:

http://luminous-landscape.com/forum/index.php?showtopic=10765

[David A. Goldfarb]

I've had that solarization effect once, and though I was aware of Adams' "Black Sun" photo, it was purely accidental in my case--

http://www.echonyc.com/~goldfarb/temp/auditorium.jpg

That's the Casino on the Asbury Park, New Jersey beachfront. At the time I think it was on the verge of being demolished, but I gather that there are now efforts underway to restore it. I think the picture works better with the black sun cropped out, but sometimes I've printed it with the black sun as something of a photographic novelty.

Now that I know that it really works, I'll be looking for compositions that might benefit from a black sun, so that I'll be able to call it an "unusual virtuoso trick."

[Janne]

Which is why systems giving "correct exposure" is not what you want, but systems giving "predictable exposure". If you always understand how it will behave, it doesn't matter if it's off by a stop or more since you can reliably correct for it beforehand.

It's just like a movie or book reviewer - you don't have to have the same taste for the review to be useful, just as long as you can reliably "adjust" the review based on your differences. Just like an exposure metering system, the best reviewers are always consistent, if not always right.

[Mike]

"I was aware of Adams' "Black Sun" photo, it was purely accidental in my case--"

David,
We'll never know,* but it might have been accidental in Adams's case too. Or, just as likely, he stumbled upon the effect by accident and then went looking for a way to apply it in a more considered fashion.

Mike J.

*Unless he wrote about it somewhere. Anyone know if it's one of the pictures in "Examples: The Making of 40 Photographs"?

[Stephen Best]

Anyone know if it's one of the pictures in "Examples: The Making of 40 Photographs"?

Yep, page 124.

[Georg]

Isn't 'expose to the right' an urban myth?

As far as I understand it, CCDs are linear devices (which they actually only try to be), so:
- the amount of actual brightness information enclosed in every bit is perfectly uniformly distributed over the entire histogramm.
- F-stops are non-linear, so they are not uniformly distributed over the entire histogram of CCD outputs.

Why do you use F-stops as unit for the information encoded in the image?

Trying to put many F-stops in one region of the histogramm is a fine way to spend time, but does not necessarily correlate to capturing more image information.

F-stops are not linearly related to image information, (but to the diameter of your iris) so why use them as reference?

Please explain. (or correct me, for that matter)

Thanks
Best

[Mike]

Stephen,
So, don't keep us in suspense--what does he say about it? Was it an accident, or purposeful?

Mike J.

[Tim Gray]

Not to nit pick, but I believe specular highlight refers reflections, such as the highlights we see on the surface of rough water. Though your point is still perfectly well made.

[Matthew Miller]

So, for the theoretical expose-to-the-right mode, it could ignore blown highlights in areas that are smaller than a certain percentage of the frame and which are significantly brighter than the scene on average. (The latter caveat important to keep it from thinking the sun reflecting off of people's faces is the same as a streetlight.)

[Mike]

Tim Gray,
You're correct--a "specular reflection" is a "perfect or mirror-like reflection of the sun's rays." However I think the term "specular" has come to be used more loosely in photography to refer to accent highlights generally, which is why I put "specular highlights" in quotation marks and explained it as something that in traditional B&W would have been allowed to render as "paper white." It's not that I'm trying to say that proper terminology isn't important, but this post already nearly ties itself in its own knot with digressions, so perhaps another digression into the proper terminology for the various forms of highlights and light sources would have been fatal (g). But thanks for pointing it out. It never hurts to clarify.

Mike J.

[Dennis]

I never really gave this too much thought ... when I read 'expose to the right' on LL, I was in a "nature photography frame of mind" and it made plenty of sense at the time. Nature photographers are accustomed to putting their camera gear away before 9:00am when the light gets "hot", so most shots would have curves that "fit" in the range of the histogram. When I started shooting other subject matter, I sort of forgot about expose to the right, generally lacking the time it takes to adjust exposure based on histograms. But it makes sense to me that this method (and an exposure mode to make use of it) would only be useful in situations where the dynamic range present in the scene you're capturing is limited.

When I read Ctein's article yesterday, it occurred to me that it didn't 'fit' with 'expose to the right' but wading through the comments, it became apparent that the two ideas are sort of complementary, but just address different lighting situations.

In both cases, though, there seems to be an assumption that the photographer will be doing his own conversion of raw files ... the photographers cranking out hundreds of event photos a day in jpeg might not appreciate the change.

[Robert Roaldi]

If you just need a bunch of jpgs straight out the camera that you don't want to spend time adjusting because of time or other constraints (or because they're not important enough) and you know your equipment well enough to expose properly in those circumstances, having the camera decide to automatically alter exposure to suit some bit-twiddling RAW requirement would be a nuisance. The camera would be fighting you. I'd hate to have an "expose-to-the-right" mode unless I could turn it off. But anyway these days, virtually all cameras have wheels that let you dial in +- exposure, isn't that enough? We only ever change two things, shutter and aperture (ok ISO too but not that often) so how many more ways do we need to do this?

[Tim Gray]

Yes, agreed. I've spent a good chunk of the last year worrying about specular reflections and diffuse reflections, so I got a little caught up in it.

[Bill Corbett]

Mike, thanks again for saying, in yet another interesting way, what I really don't think can be said too much these days...and what is nice to be reminded of; that photography is about seeing, first with our hearts and minds, and with our eyes and only then with our cameras.

Seems we all enjoy and feel that we need the advances of newer gear. But last summer, I went tent camping in the Shenandoah Valley of Virginia with my old Pentax 35mm film camera and only a 50/f2 prime. My goal was to share my life for a week with deer in the valley... to see how close I could be to them, how much they would trust me, especially with their young. Telephoto lenses would not do for this project. (Of course, when I grabbed a pretty good shot of a nice sized black bear that surprised me from only about fifteen feet away, I had a little trouble convincing myself right then that my goal was to interact.) It was a great week and several up-close images of curious and trusting fawn and their mothers now grace my scrapbook. I know Shenandoah is a protected, very tame part of the world, but being able to literally touch a fawn with its mother close still takes a lot of patience. It's worth it though. On the long trip home I thought about Street photography, my passion. It's a lot like that week in the Valley maybe. Sharing, patience and just simple gear.

[Michael]

I think an even more useful setting than expose to the right would be an ISO setting. You would select the shutter speed and aperture and the camera would then set the required ISO. This should be very easy for the camera makers to incorporate. Canon could make this an alternate use for the virtually useless print button on their dslr's.

[R.W. Bloomer]

"Ansel Adams, Photo Booth Self-Portrait, c. 1930" has my head spinning. Thank you, Mike, thank you.

[KeithB]

Maybe what we need is a log-responding sensor.

I would envision a sensor with each pixel constantly monitoring its value. The pixel would "know" the exposure time and if the pixel got full at 1/2 the shutter time it would "dump" the charge and start over. When the data is read, the pixel also reports wether it had dumped charge or not so that the software will know what the "actual" value would be.

You could also include multiple check times at 1/4, 1/2 and 3/4 of the shutter time.

[Martin Doonan]

I've just read Thom's comment and have a slight counter to it. My idea of ETTR would be a metering option for A/S/M modes, essentially something that would give me more chance of avoiding blown highlights in mixed or variable light. I'm looking for (in some cases) assitance in getting closer to the best exposure first time out. With mid-tone based metering, I'm having to do a lot of exposure compensation & so I'd like a switch to help. Canon are closest with the new higlight priority mode.
I still want all the data that Thom presents as well.
Trouble with ISO rating and mid-tone metering is that it is based on shadow noise and maximum low-end detail (I read ISO 12232).

[Ctein]

Dear Georg,

The simplest answer is that you are not doing data collection with your camera, you are doing photography.

The eye behaves logarithmically* -- "stop" changes in exposure appear equally spaced to the eye*. Linear changes in exposure don't.

If we were Borg, with silicon-sensor eyes, then a linear-step scheme would make photographic sense. We are not, and we should not be jumping through cognitive hoops to act like a silicon sensor. That will NOT make you a better photographer, nor make your photography easier.

pax / Ctein

*(well, no, not exactly true, but that's an entirely different topic)

[Bruce]

Making the overexposed highlights blink black and white was popular on some point and shoot cameras for a while. Others would blink the underexposed areas in blue and the overexposed areas in red. This location specific feedback is more valuable to me than a histogram. What is going on is important, but *where* it's going on is more important. Which is the point of the article above.

On a side note, imagine a camera that is able to use false colors to display what areas of the image are in focus and what are not.

Computing power inside of cameras is going up and costing less. Technological limits for some of these display tricks are going away. Imagination and a little bit of courage by camera manufacturers are what is needed to make cameras do a better job of reporting tonality to the photographer.

[thigmo]

Does anyone have a recent Olympus DSLR? How well does the spot highlight/shadow mode work? Is this not what you're essentially looking for? (I would think Mike would appreciate the E-510 with its shake reduction sensor.)

Despite the 4/3 mount system's faults (and having invested into other systems already), Olympus did seem to think about this aspect of exposure fairly well.

From the E-410 manual:

HI Spot metering - highlight control
When the overall background is bright, white areas of the image will come out gray if you use the camera’s automatic exposure. Using this mode enables the camera to shift to over-exposure, allowing accurate white reproduction. Metering area is the same as spot metering.

SH Spot metering - shadow control
When the overall background is dark, black areas of the image will come out gray if you use the camera’s automatic exposure. Using this mode enables the camera to shift to under-exposure, allowing accurate black reproduction. Metering area is the same as spot metering.

[David A. Goldfarb]

The attribution of this interview is unclear, but here is what looks to be Adams' description of how he made the "Black Sun"--

http://www.philpankov.com/-/philpankov/article.asp?ID=2188

It sounds like he knew it could be done, and he was interested in the possibility, but actually achieving it was something of an accident. He processed one neg of the scene in D-23 (a metol-sulfite developer not unlike Microdol-X or Perceptol) and one in what he describes as a compensating pyrocatechin formula (probably Windisch), and the sun in the pyrocatechin negative reversed.

My neg was TXT (the version of Tri-X sheet film that preceded the current TXP) processed in ABC pyro (AKA Kodak D-1), which raises the question of whether propensity for solarization might be a property of staining developers.

[Ctein]

Dear Mike,

I'm mostly with you, tho' I'd also implore you not to use 'specular highlight' incorrectly. Most photographers are confused (and wrong)enough about sensitometry and photometry as it is. I'd rather not make it worse.

But that nit aside... "expose to the right" is nothing different from "expose for the highlights" as we used to say for slide film. Or, for that matter, it's the exact counterpart to "expose for the shadows" for negs.

And what's important about all those rules is that they require human judgment. People who tried routinely exposing their negs for pinpoint-maximum shadows when those didn't include important subject content quickly found out that they got wildly overexposed negatives.

The reality is that simple averaging metering gets you good results about 75% of the time. Center-weighted metering kicks that up to about 85%. Automatic matrix metering gets you 90-95% good results.

Ya want better than 95%? "Expose for the highlights" won't get it for you. That takes judgement.

It's also computationally VERY expensive compared to other metering modes, to do it correctly.

pax / Ctein

[Stephen Gillette]

Whoa, Nellie...

What jumps out at me from Thom's comments is that the histogram--live or otherwise--is much less valuable for raw shooters than we have been led to believe.

I have been mending my wicked ways since acquiring a Canon G9 and using the histogram during framing and capture. Doing so adds one more mental step to the process of shooting, and sometimes it means further exposure adjustment. All to please the histogram (and presumably get the best exposure data in my raw file).

As I'm interpreting Thom, the histogram is a great concept with a wobbly implementation. Is that correct, in a nutshell?

[Mark S.]

Though automatic functions are nice, photographers need to not forget how to expose manually, whether it is film or digital. Automatic settings do not give you the freedom to take different types of shots in a given shoot session. You get locked to the settings of the camera. Long story short, with some practice, it's easy enough to expose properly for any situation (that's why Mr. Adams thought of the zone system...), and the more you do it your self, the better you will get at-certainly far better then the camera ever will be. The best tool for determining correct exposure: Your brain.

[SteveW]

It may be a long way off, but given the many different needs and desires of people using the same equipment, I think what we really want is an open source option for exposure settings and even certain camera controls. Custom settings and buttons are a nice start, and the higher end cameras already have this, but I expect many serious photographers would welcome metering, controls, and menus systems customized to meet their typical subjects and shooting styles.

[dasmb]

Mike -- there's no reason why an ETTR mode wouldn't have EV adjustments, same as any other metering mode. In this case, they would control exactly how much of the scene was clipped (either into the black or into the white).

Though it's the bane of outdoor daytime photography, clipping can be fun, even essential indoors. I hadn't intended for this shot to clip -- and yet it's one of my best for the year:

http://megapixelated.com/2007/03-17%20SXSW/slides/_MG_6284.html

[chuck kimmerle]

Didn't see a response to Georg's query regarding "exposing to the right", but if there was one and I missed it, apologies.

"...the amount of actual brightness information enclosed in every bit is perfectly uniformly distributed over the entire histogramm."

If you're saying that there is as much information in a highlight as there is in a shadow, then you're incorrect.

With digital sensors, any exposure level will have only half as much information as an area one-stop brighter (twice as bright). That means that the brighter areas of an image have vastly more information that the shadows. For a more detailed explanation, check out the Luminous Landscape page at:

http://www.luminous-landscape.com/tutorials/expose-right.shtml

Chuck

[Peter]

How is Thom's "underutilization" different from the noise floor?

[Herb Martin]

This may be a naive question, but why does the digital sensor have to record data linearly? Surely some programming could be used where values taken near the recording limit of the sensor could be interpreted in a logarithmic fashion, thereby enabling a film-like rendition of highlights, and a greater dynamic range.Just curious...

[jthirsty]

Michael:

The Pentax K10D has exactly the mode you describe, TAv. Why other manufacturer's haven't duplicated it, who knows?

[robert e]

Mike, Thom, et al,

I remember shopping for a low-end digicam about three years ago, and gravitating toward Pentax because, unlike most digicams, at least some of their models seemed to be set to underexpose rather than blow out highlights, which seemed like a good idea to me. Consumers and reviewers disparaged the darker, noisier output as a design flaw.

I agree with Thom in general that for RAW-centric strategies like auto-ETTR to be practical, we need more information, but at the same time what he asks for seems an overwhelming amount of data to process.

One practical implimentation of Thom's thesis may be to allow the photographer to customize both in-camera processing strategy and data display for for an overall capture-to-print strategy.

I'm not sure why people insist or assume that all proposed features and cameras cater to novices (I guess that's where the money is), but in this case that is easily done. To go Thom one further, the variables should be incorporated in the existing scene modes, like all the other variables. The camera would let highlights blow out in Halloween mode, ETTR in theater mode, and process accordingly. That may already be the case as far as I know.

But the new idea I see in this conversation boils down to having enough control over preview/review, i.e. in-camera processing, to match the intended shot-to-print strategy. I like it. Chimping is one of the most important innovations delivered by digital shooting, and it's time we take as much control over it as we have over exposure. Of course, we'd then have to learn enough about it to make good use of the controls.

[Mark Roberts]

Outside the question of whether an "ETTR" mode would be good or bad, keep in mind that if you're shooting RAW the histogram shown on the back of your camera (on all models that I'm aware of) is based on the embedded JPEG in your RAW file. So you have more headroom than is actually shown. You can clip the histogram to the right slightly and still not blow out the highlights in your image. Practice and experience will show you how much you can get away with.

As for the comment, "I think an even more useful setting than expose to the right would be an ISO setting. You would select the shutter speed and aperture and the camera would then set the required ISO."

Such a camera already exists: The Pentax K10D.

[Stephen Best]

Mike:

"So, don't keep us in suspense--what does he say about it? Was it an accident, or purposeful?"

In typical Adams' fashion he conceived it all in an instant and already had a compensating developer "planned for the desired reversal effect" (Windisch Pyrocatechin if anyone cares). But maybe all this is BS and instead he spent some time scratching his head over the results until one of his darkroom assistants (a fourteen year old kid from down the street) clued him in :-).

[Dave Sailer]

OK, if any of you have pull with the camera makers, feel free to start your negotiation bid with auto expose-to-the-right, Digi-Qwik Zon-O-Matic (TM) systems.

Then allow yourselves be beat down to getting us manual focus, manual aperture and manual shutter speed settings on one or two small, convenient cameras.

I'm happy to bracket. And I will be your pal forever if you can just help me get back to making my own dumb mistakes. (I'm good at that, having had lots of practice.)

I'll even help you to continue pleading for more robot control on all the rest of the cameras made. But later, after we get one or two real cameras back. Costing less than $8000, etc.

[Jobo]

Dennis & Robert: If your camera exposes to the right to get the most data out of the exposure, you could still have in-camera JPEG processing bringing the average tone down to middle gray, or something suitable. You'd even end up with a better in-camera JPEG...

And I guess ETTR would just be another metering mode, not even replacing matrix metering for at least a decade if ever.

[Bruce Robbins]

An ETTR mode would make perfect sense providing it could be switched on and off. It's very easy to look at a scene and decide whether it has specular highlights. If it doesn't and you're so inclined, switch to ETTR. If it has, just carry on as you do at present with whatever exposure mode you like to use. Where's the problem or difficulty in that? Such a mode would be much more useful that half the rubbish they crowd around mode selector knobs these days.

[Peter Croft]

Mike, I don't understand something about blogs here. I want to keep this article and ideally, I want to retain its appearance, images, formatting etc. But how do other people extract just one item from all the others on the page?

I usually print articles to pdfFactory, ie print to a pdf document for later reading and filing, but for some reason, many pages like yours just won't print more than the first page. I can save as html, yes, but that saves the entire page, end to end. I could cut and paste, I suppose, but to fire up a word processor seems excessive and the appearance is lost. What do people do?

The other problem I see with blogs is that the page gets SO long and has to reload all the images every time we access it. Until a week ago I was on dialup and it meant I had to Adblock most images. Some blogs were just so impossibly slow that I couldn't visit them. I've now got wireless broadband so it's not such a problem, but couldn't or shouldn't the page be divided up a bit more?

Great reading, though. I love the site and visit every day without fail.

Pete

[Mike]

David,
'moonrise over Fernandez'???

That "interview" smells more than a bit suspicious to me.

Mike J.

[Mike]

"Long story short, with some practice, it's easy enough to expose properly for any situation (that's why Mr. Adams thought of the zone system...), and the more you do it your self, the better you will get at-certainly far better then the camera ever will be. The best tool for determining correct exposure: Your brain."

I remember a story told by a friend who went photographing with John Sexton at Point Lobos. John left his spot meter at home. The friend asked if he wasn't using the Zone System. John said something like, "I've photographed at Point Lobos a hundred times. If I don't know the light by now I never will." I'm paraphrasing....

Mike J.

[David A. Goldfarb]

"Fernandez" indeed--and I doubt Adams ever followed the British convention of calling his camera a "10x8." That said, the details of the "black sun" image seem about the same as what Stephen paraphrased from _Examples_, and about what I'd expect of Adams.

[Anurag Agnihotri]

ETTR...isn't that all these underexposing 400D's have been doing :)

[DWBell]

Interesting article. I ETTR when I choose to and almost have all the tools I need already. Here's how, followed by what I need to be improved to make me perfectly happy.

Spot metering TTL. I have previously tested the DR of my sensor in true Adams style. Let's say it's 5 stops. I look at my scene, engage my brain and decide which highlights I can afford to loose and which I want to keep. I then spot meter on the lightest highlights I want to keep and adjust exposure until the needle is at +2. I now know that everything at and below that level will be maximized. That's it.

In parallel I set my camera to raw, but also set my in camera JPEG settings to be as close to raw as possible. Normally no sharpening, low contrast and low saturation. This combined with separate R G & B histogram display will confirm my exposure choice (roughly) while reviewing after the shot.

What I would need to be really happy is

a) a more accurate histogram from the raw capture, not from the in camera JPEG.
b) EV adjustment of +/-3 stops. I don't like to "centre" the needle on +2 when I can't "see" +2 1/3, it's a user thing, but significant.
c) A smaller spot meter in camera, my current one is 3° but takes up a suprisingly large area of the view finder.

Kind regards
DWBell

[Tim]

`Isn't 'expose to the right' an urban myth?'

Not really. At the bottom end you've got noise lurking like a dragon in the cupboard.

Mike: I see your point with expose-to-the-right not always working if you want wash-out. This is why I detailed my own variation, which I think should simply be called "tone-placement". Most of the time for scenes without specular whassits and/or avoiding the sun, it works perfectly. Just point the camera at the scene, wave the spot around, make sure all the objects' brightnesses fall where you want them on the exposure scale, compose and shoot.
You might know that the brightest parts of a cloud want to be bang-on the brightest values recordable before the camera says off-the-chart; you would expect the same exposure to show tree foliage as -1.5eV or less; you would expect the same exposure to show the palm of a caucasian hand as about +2/3rd eV; you'd hope that sunlit grass would be about a midtone (within wide tolerance); you'd expect it to bear some resemblance to Sunny-16.
Or indoors, you might take the flare of a light up against a wall and position somewhere in that as max-recordable, let the lights themselves blow out and hope that dark woodwork still has enough detail left.
It's fair to say that if I didn't get the results I expect this way, I'd be returning an offending camera as faulty.

Incidentally, I thought Olympus digicams *had* highlight-placement metering; there's been such a thing since at least the e-500 and also in the E3, IIRC.

[Thom Hogan]

Is the info I'm asking for too much to present and distinguish? I don't think so.

There are three problems to solve with what I ask:
1. Getting the data.
2. Displaying the data.
3. Allowing user preferences for the data.

Of these, #2 is actually the easiest to solve. I think Nikon Capture was the first to do the "show only the overexposure or underexposure" thing (press L for Light or S for Shadows if I remember right [too many products to remember!]). You now see relatives of that in products such as Lightroom (hold down the option key, click the triangles, etc.). On a camera with as many controls as Nikon's DSLR, it should be easy. If I'm in a histogram display, rotate the Rear Command dial to go through Histogram Only, Histogram with Blow/Brownout Overlay, Blown Areas Only, Brownout Areas Only, back to Histogram Only. I can think of several other ways to do what I want, but what I described would be good enough I think, and consistent with Nikon's current techniques. It certainly would be better than what we have.

Oh, one other note: the histogram itself would have to be presented more like what Kodak did with the Pro 14n for JPEGs. We need clear indicators where the assumed noise floor is and where the "no channels have blowout" point is. Indeed, this leads me to the way I would display the information: orange for areas of the histogram in which all channels are between the noise floor and the well capacity, and colors for areas where a channel or channels is below noise floor or at well capacity (R, G, B for the single channel, C, Y, M for the two channel, and White for all channels).

Of course, no manufacturer wants to indicate a noise floor, do they? They're afraid it would be a competitive disadvantage. Okay then, make the noise floor user definable via a Custom Setting, and set the default at 0,0,0!

[Rob Griffin]

To go along with the John Sexton comment, I read an interview with Brett Weston where the interviewer asked Brett if it was true that he didn't use a light meter. Weston answered that if he had a particularly bad hangover he might wave one around a bit after he made the exposure. Weston always used the same film, film developer, paper and paper developer, he had his process down and he was no doubt consistent about it. My guess is that there is probably no metering scheme or system that can replace experience, consistency and a sharp mind.

Rob Griffin

[Ctein]

Dear Folks,

I find too many of the posts in this and the previous thread disquietingly reminiscent of the blind men feeling the elephant. It is all well and good to wish to minimize noise in your digital photos. But noise is not the whole elephant.

After having read many thousands of words on the subject, here and on LL, I can tell you very simply, and in plain English how to expose your film.

*IF* the entire subject luminance range fits within the capture range of your sensor, expose as generously as you can without sacrificing highlight detail.

*IF* the luminance range exceeds the capture range of your sensor, adjust the exposure so no important highlight detail is clipped... *UNLESS* ...

... this pushes important subject detail so far into the shadows as to seriously compromise overall image quality. Then you must COMPROMISE on the exposure that produces the best-looking photo overall.

Astute readers may observe that (a) this is not rocket science and (b) it's remarkably similar to the rules you'd have used to expose slide film.

KISS.

pax / Ctein

[Barry Reid]

Isn't it just best to figure out how your digicam of choice works, learn to expose to suit it, learn to take advantage of its quirks and wrinkles and finally, not upgrade every time a new model comes along, so that you can exploit that knowledge?

[Cassio Dorneles]

I think it would be very hard to get a correct metering to ETTR. You would need to spot meter the whole scene to get the highlight point and expose it to right side of the histogram.

But even this way you will eventually get some blown highlights: The spot meter meters an area which 'contains' various pixels and exposing to put the average of this area in the right means that some pixels can blow.

Another approach would be to use the sensor as a meter. Take two shots, one for metering and then the real shot, the same way we currently do. The processing of the metering shot would have to be very fast and probably just top-line cameras would be able to do so.

[Nicolas]

I wouldn't appear as also trying to feel the elephant, but...
I do second a "ETTR" metering mode - yes it should only be another matrix metering mode for me.
The simpler way to implement it would be to make the matrix metering behave "normally" (ie for middle gray) while shooting Jpeg, and ETTR while shooting RAW... But it would be nice to be able to choose in the first place, of course.

As Thom said, any automated metering is doomed to utterly fail - I only see them as a quicker way to get the exposure in the ballpark, ie that the "good" exposure (yes, it's something a bit too tricky to automate, so far) is within reach of the exposure compensation dial (2 stops on my Canon) - at least most of the time.

And about "specular highlight", a dirt'cheap (but maybe effective?) trick could be to use relatively large metering zones, to average such specular highlights (they are tiny, by definition, aren't they?).

Yes, you'll always have to rely on a manual control of the camera (EC dial, M mode or whatever), but for those of us that aren't Ed Weston (a few at least?), we'll also rely on a light meter to give us a first idea of what should be done with exposure. The more precise and informative, the better!
So I'll also second Thom's proposal about more information on the review screen.

[tom]

I often find that the camera meter is a full stop or more less than what it could be.

I don't mind if specular highlights blow, but thoughtfull exposing to the right will give you better image quality.

In people pictures you do not want the red channel to blow.