The Online Photographer

A Proposal To Redefine Digital ISO

By Ctein

The definition of ISO is based only partly in the physical sensitivity of film or sensor. ISO is a judgment about what exposure will produce the best results, on average, with a particular medium of capture. ISO is a compromise.

In 1955 Tri-X had an ASA (ISO's predecessor) of 200. In 1965 it was 400. The film hadn't changed, just the official judgement of what the best exposure was. Higher exposure of B&W film produces better shadow detail, but increased grain and poorer sharpness. Shrinking film formats increased the importance of grain and sharpness in overall quality. The manufacturers decided the emphasis was too much on shadow detail at the expense of those, so ASA values were redefined. Negatives need sufficient exposure to produce shadow detail while not overly compromising grain and sharpness. Slide films must record sufficient highlight detail without having a slide that's unacceptably dark. Many negative photographers routinely "overexpose" by around a stop*. Many slide photographers "underexpose" their photos. We're all aiming for adequate information at the end of the luminance scale where the medium is most likely to fail us. ISO doesn't require you make a certain exposure; it's merely a best guess. But when ISO consistently guesses poorly for a majority of users, it ain't doing what it's supposed to.

Digital sensors have problems similar to slide films; expose more than a certain amount and there's simply no detail. Unlike slide film, digital sensor's behavior in the highlights is not at all graceful. Once the pixel's potential well is full of photoelectrons, clipping occurs. In a purely linear device, that can happen 2–3 stops above middle gray (there are ways to improve that—many cameras do much better).

At the same time as the highlights are getting clipped, there is usually detail well into the shadows, albeit with increasing grain/noise. Cheapo digital cameras can capture a seven stop range; better ones 9–11 stops. In many cameras the luminance capture range is weighted too far in favor of shadows. Especially true as we notice loss of tonal separation in highlights a lot more readily than we notice it in shadows.

From the comments I read about digital cameras (and my own modest experience) I think the digital ISO is simply too low in many (not all) cameras, often by more than a full stop. Many of us have already learned to "underexpose" as normal practice to more usefully balance highlight and shadow detail. We just set our exposure compensation dial for –1 or –1.5 stops and leave it there most of the time. This needs to be institutionalized. Digital ISO is due for reformation to provide exposures that more usefully exploit the sensor's exposure range, balancing adequate shadow and highlight range. On my Fuji Finepix s6500, changing the current ISO of 100 to ISO 250 would be about right.

Both of these photographs were originally made in RAW mode by my Fuji FinePix s65000 camera. (Click on the images to see them larger.) The one on the left was made at ISO 100 with no exposure compensation. The one on the right was made with –1 stop exposure compensation. Both of these photographs were originally made in RAW mode by my Fuji FinePix s65000 camera.

The one on the left was made at ISO 100 with no exposure compensation.  The one on the right was made with –1 stop exposure compensation. I made a curves adjustment in Photoshop to the image on the right, so that the shadows would have about the same brightness in both photographs, for comparison purposes.

The "normally" exposed photograph has blown-out highlights with little or no data in one or more channels. The "underexposed" photograph has good highlight detail and only a slight loss of clarity and separation in the shadows. So, which one would you say was correctly exposed?

There would be side effects. A good one is that you get more low-light capability. Instead of hand-holding at 1/10th of a second, you're hand-holding at 1/25th of the second. The bad is that your pictures become noisier. It's a balancing act, just as defining B&W negative ISO was a balancing act between shadow detail, grain, and sharpness.

But, digital image noise is already better than comparable speed 35 mm film in many digital cameras, and it continues to improve with each generation of sensor. Luminance capture is definitely not better than film in the highlights. I understand the current obsession among the digital newbies for low noise; I'm a fine-grain lover myself. But poor tonal placement is a worse problem that will improve less as sensors get better; it's more inherent in how the sensors map luminance values. We need a new ISO definition and we need it now.

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Ctein

*(By the way, this has nothing to do with the misconception that manufacturers overrate negative films by half a stop or so.  That's mostly due to mistakenly metering off of 18% gray cards using ISO-standard meters calibrated for 12% reflectance.)

Which Erwitt?

A friend just contacted me. He's thinking of adding an Elliott Erwitt print to his small but high-quality photograph collection (I know he's smiling at that description, since he owns a couple of my prints), and he wanted my input as to which ones are my favorites.

Lord, that's like asking me what's my favorite breath of air. Some are better than others, but I like them all. "Favorite Erwitt" is redundant!

I ended up telling him that if it were me, I'd probably buy a dog print. I have as much affection for Erwitt's dog pictures as Erwitt has for dogs. My sentimental favorite is probably the one of the little white dog jumping up in the air next to the legs of a splay-footed man in a raincoat, because I have a hazy memory that the man is actually Erwitt himself. I also really like the bulldog-in-the-lap picture. But then, once I start thinking of Erwitt's dogs, it becomes a mental parade that's not easily extinguished. What about the big old Airedale with the stick in his mouth? The dog on the rooftop?

The only ones I might avoid would be the photojournalist pictures that are now celebrity pictures, like JFK, Jackie, and so forth, only because celebrity pictures seem a bit obvious as purchases and they miss the special whimsical humor that's so characteristic of Erwitt. (Besides, if I were going to buy a picture of JFK, I'd see if I could buy one of Jacques Lowe's.)

One thing I really agree with is that an Erwitt picture would be a lovely thing to have around the house and look at every day. I applaud my friend's decision.

Elliott Erwitt by Alec Soth

So let me pass along the question. If you had to choose only one, which one of all his prints would you choose to own?

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Mike  (Thanks to Steve R. and Kim K.)

ADDENDUM: Can't decide?

Featured Comment by Stephen Gillette:

-                                                                                  (Kind permission to manipulate granted by Alec Soth.)

Hearts on Our Sleeves

"Diane Keaton on Photography," a lovely little essay written by novelist Larry McMurtry about his friend and her photo book projects, for the New York Review of Books.

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Mike (Thanks to David E.)

New GR Digital (and other news)

Ricoh Announces Ricoh GR Digital II

Ricoh Corp. has announced an evolutionary update to its popular GR Digital, which has been on the market for exactly two years, since October 2005. Called the GR Digital II, the new camera features logical updates such as a 1/1.75-inch CCD with 10.01 million effective pixels, a 2.7-inch, 230,000-pixel display with a high 160º viewing angle, and a new processing engine said to "dramatically" improve high-ISO noise performance. It has the same excellent, fast, 6-element in 5 group 28mm-e ƒ/2.4 lens as its predecessor. Other features include .dng RAW, a native square format feature like that found on the GX100, customizable B&W modes, and electronic leveling with visual or audible confirmation. New accessories include a new teleconverter lens that makes the lens into a 40mm equivalent (right), and a new external viewfinder.

Write times for RAW have been improved from 11 seconds to 3.8 seconds, and you can now take a second picture in RAW while the first is still writing. RAW capture works in the camera's square format, too.

Availability is said to be set for a month or two from now.

Canon Recalls EOS 1D Mark III's from Dealers
Canon has apparently found a definitive fix for the autofocus irregularities first brought to public attention by Rob Galbraith on his excellent website—it's a  misadjusted AF sub-mirror, thought to affect only a minority of cameras. For those who already own 1D Mark III's, Canon will check your cameras and repair them if needed, but will not offer refunds or replacement. Canon has also taken the unusual step of recalling all 1D Mark III's now in dealers' hands. There's no word yet on when the camera will resume shipping.

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Civil Rights photographer Ernest C. Withers, a son of Memphis, Tennessee, was as  proud of some pictures he didn't take as he was of many that he did: he was granted access to see Martin Luther King Jr.'s body at the morgue following Dr. King's assassination and refrained from taking "morbid" pictures because he didn't want Dr. King to be remembered that way. Mr. Withers died this month at the age of 85.

Phase One and Microsoft Team Up
Microsoft Corp. and Phase One recently announced a strategic alliance to explore ways to work together to develop solutions for the Microsoft Windows platform. Phase One is a leading provider of digital image capture and work flow management technology, including P+ Series digital backs and  Capture One software. Phase One is an employee-owned company based in Copenhagen with offices in New York, London, Tokyo, Cologne and Shanghai.

Chantal's New Website
Chantal Stone, who wrote a series of posts for T.O.P. last year about notable photo blogs around the web, has a new website herself now. Check it out!

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Mike  (Thanks to David Rosenberg, Christopher Lane, and Dirk Rösler)

Catalogue Raisonné

A catalogue raisonné (RAY-zon-ay), for those of you who might not know the term, is a book that shows the full range of an artist's work in sequence. Technically, a true catalogue raisonné has to meet a number of scholarly conditions regarding completeness, with notes on condition, provenance, and location of the works, among other things, and it needs to address any questions of attribution. Because not all of this pertains to a mechanical printmaking medium like photography, the term is perhaps not strictly applicable.

Still, the splendid new Ansel Adams: 400 Photographs published by Little, Brown is the closest thing we've gotten yet to a catalogue raisonné for Adams. It might not cover every negative he ever made, but it certainly contains all of his major work, divided into five periods beginning in 1916 and continuing through the 1960s. There are things here even I didn't know, and I thought I'd seen everything.

It's not a large-scale book (and not expensive, either—a mere $26.40 if you buy it through the link, making it very good value for money until the price goes up), but the pictures are large enough to enjoy. The reproduction, consistently very fine although not quite matching the best, will not stand in the way of anyone's enjoyment either.

Useful as an introduction to Adams for those who don't know his work very well, or as a handy single-volume  survey of all of his work in chronological periods for those who are diehard fans. For anyone with a general interest in great photography: warmly recommended. For lovers of landscape and nature photography or fans of large format: essential. For Christmas and Hanukkah: you could do a lot worse!

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Mike

Town and Country

The lower of these two pictures reminds me of a story. I was a high school photo teacher when I made these, and I made a 16x20 print of the lower picture and tacked it to the bulletin board in the art department near the school darkroom. The negative is perfect, so the print was quite beautiful, and I was proud of it. One day I saw two of my students standing at the board looking at it. They hadn't seen me and probably thought they were alone. I eavesdropped, thinking I might get some useful feedback. I expected they'd say something about the print quality, since they were used to 35mm Tri-X prints and didn't often get to see 4x5.

They regarded it placidly for a while, and then one said, "Must be Mike's. Only Mike would take pictures of farmland."

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Mike

Page Spreads

I started this project as a result of receiving a $650 (woo-hoo, big money!) faculty grant from the school where I was teaching. I used the money to buy a bunch of Polaroid film. Before I left home I did some test prints of the National Cathedral from various places around D.C.—sort of a fun project in itself—and made some prints so I could see how the materials behaved. I'd never used 4x5 before, so naturally I was impressed with the level of detail I could get in a large print (the prints I made were on 16x20" paper with a 1-inch border all the way around).

So all summer I semi-consciously had two conflicting ideas in mind. For one thing, I conceived of the pictures as ending up in a book, so I was constantly thinking in terms of page spreads. (Remember, it was Polaroid, so I could futz with the little positives in the evenings, trying out pairings.) But the other thing I constantly found myself doing was paying attention to very small details in the pictures, relying on the materials to reveal these things in big prints.

Of course, sometimes I took this a bit too far. This is probably the worst instance. In the top picture, of the building of Petoskey's Bayfront Park, one worker's head kept bobbing into and out of view from the far side of the roof, and I timed the shot to get his disembodied head sitting on the roof peak. I don't know, but now I think it's asking an awful lot to expect a detail like that to carry a picture—did you even notice? I don't think it helps the picture at all. Even in a big print, never mind a book-sized one.

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Mike

Pure Michigan

For me, these two pictures are the very heart or core of my old Michigan project. They're both simple, plain pictures, and perhaps they might come a little too close to cliché for some people who have a more profound appreciation for the State. And Michigan is not the only place you might see these things, of course. But for the me, the juxtaposition of a corn field and pine trees is a very Michigan-y take on America's most ubiquitous grain crop, and I get a smile every time I see this golf course picture—golfers with hand-carts on a course with a barn on it, that's just very Midwestern for me.

The original prints of all these are about 18" wide, and the scan of the second picture (although you can click on either image to see a slightly larger version) is almost too small to see—the green is in front of the barn, and the bright spot on the side of the barn is the flag on the flagstick.

John Szarkowski thought the top picture "just missed" because it's too clean—he thought it needed a snippet of road or fencerow in the corner or on one edge, to save it from perfectionism. And the second picture is the only picture of mine that is in a major Museum collection.

I think of these two pictures as "pure Michigan," each in its own quiet way.

Corn and Pine, 1987

Michigan Golf, 1987

Incidentally, all of these pictures were taken with a 4x5" Wista 45DX on Polaroid Type 55 positive-negative film.

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Mike

Dry Brush and Santa Ana Winds

A photograph submitted to the L.A. Times by an unnamed Irvine resident shows a woman watching the approach of the Santiago Canyon Fire from Quail Hill.

I don't often interrupt the proceedings here to discuss current events, but in recent days my thoughts have been with our neighbors and countrymen in Southern California, who have been dealing with catastrophic wildfires over the past six days. The figures are staggering: 772 square miles of populated land (half a million acres) have burned, fed (and unpredictably spread) by harsh, swirling Santa Ana winds. Seven persons lost their lives, along with many pets, wild animals, and livestock. More than 1,800 homes, many extremely valuable, have burned to the ground or are a total loss. More than 500,000 people had to be evacuated, most from San Diego County—the largest mass evacuation in the State's history. The final cost of the disaster will be measured in the billions of dollars. More than 13,000 firefighters were involved in fighting the fires, which are now largely, though not completely, under control.

Interestingly, many news services linked to selections of amateur photographs of the fires on flickr and other photo-sharing sites.

Our thoughts go out to those who have been dealing with the loss, disruption, and danger created by the fires.

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Mike

Hong Kong's Forgotten Photographer

By Liam Fitzpatrick, TIME magazine

In the Autumn of 1997, Yau Leung was just starting to earn a minor artistic reputation when he slipped off a ladder in his studio, hit his head, and died. That the light should have left the eyes of Hong Kong's greatest photographer in so banal a manner makes contemplation of his passing especially difficult. If photographers are not felled covering disgraceful coups or scrappy jungle wars, posterity likes them to advance to gurgling senility, feted by models, retrospectives and hand-numbered editions. There is no romance in death by lapse of concentration — especially not in a man whose defining artistic characteristic was his undivided presence in, and intense focus on, the moment.

Hardly any of Yau's works are on public display in Hong Kong (although a few pieces were recently hanging in the Heritage Museum as part of a temporary exhibition on the history of cameras). He did not leave a family. His books are out of print or hard to find, and his prints are not available for purchase from any local galleries (however they can be bought from a small one in Toronto, established by the Hong Kong photographer Lee Ka-sing). Outside a tiny circle of dilettantes, nobody knows his name. Thus, 10 years after his death at the age of 56, Yau continues to be as obscure as he was in life....

READ ON

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Howard French

Photo: Pictorial Publishers Ltd.