Ansel Adam's Law

[Ross]

According to you, whether can apply Ansel Adam's law (exposure for shadaw, development for highlight) in digital photography?

[Dave Humphries]

Hi Ross,

Welcome to the CiC forums from me.

Could you be a little more specific please? - I assume you have read something in one of Sean McHugh's Tutorials or Techniques pages that has prompted this question, but without knowing what you have read, I think we fail to answer your query properly.

Thanks,

[PopsPhotos]

Ansel Adams exposed to make sure the shadows had detail and texture. Then he chose the developer and developing technique to prevent washing out the highlights. Some times he would even do a pre-developing dip or a selective sponge application of developer to achieve the development of the negative that he was reaching for. This is similar to the "selective dodge and burn" used during printing.

I'm sure one could emulate the process in advanced post processing, starting from raw and using masking, selections, layers, magic wands and handwaving at the proper steps during the process.

I've done some of this back in the days when I had my darkroom, but I am waaaay behind the curve in doing this with PS and that ilk.

Pops

[Ross]

Thanks a lot Pops. I'll try step by step in Photoshop.

Ross

[arith]

I don't know Ansel Adam's and I'm a bit sceptical of Laws. But you might be infering to exposing to the right, or even HDR. In digital, if it is blown it is gone.

I think the pioneers worked in film, and digital is made to look like film to sell camera's, but in reality it is completely different.

[Steaphany]

Actually the rule "exposure for shadow, development for highlight" was the method that Adams employed to get a handle on the latitude, i.e. dynamic range, of the photographic materials that he was using and is actually all part of the Zone System developed by Ansel Adams and Fred Archer.

A key feature of using the Zone system is to maximize the utilization of the complete dynamic range available while preserving texture and detail within the central zones.

A google on "ansel adams zone system" yields over 35,000 hits and the best articles that I found are:

Zone System From Wikipedia

A Simplified Zone System By: Norman Koren

First, the Zone Systems breaks down the dynamic range of Black to White into 11 Zones ranging from Zone 0 through to Zone 10, and Zone 5 corresponds to middle grey. A key feature of the Zone System is the realization that Zones 0 and 1, Pure black and Near black with slight tonality but no texture, along with Zones 9 and 10, Slight tone without texture - glaring snow, Pure white light sources and specular reflections, are devoid of sufficient detail to offer any visible textures.

"exposure for shadow, development for highlight" comes from this Negative Film exposure procedure:

1. Visualize the darkest area of the subject in which detail is required, and place it on Zone III. The exposure for Zone III is important, because if the exposure is insufficient, the image may not have satisfactory shadow detail. If the shadow detail is not recorded at the time of exposure, nothing can be done to add it later.
2. Carefully meter the area visualized as Zone III and note the meter’s recommended exposure.
3. Adjust the recommended exposure so that the area is placed on Zone III rather than Zone V. To do this, use an exposure two stops less than the meter’s recommendation.

When employed for digital photography, just as with color reversal film, the normal procedure is to expose for the highlights, "Expose for the Right", and process for the shadows.

I have adapted the Zone System to my digital process flow with the following chart:

Where 0 EV corresponds to the digital value 128 and middle grey. I then break the dynamic range into 15 Zones and employ a power of 2 ascending and descending logarithmic scale that covers every possible value except for 0 ( Black ) and 255 ( White ), obviously values where data is potentially lost.

In use, I have my tools set to warn me of any pixel value that is below 16 or above 239. If elements of an image ever fall above or bellow these zones, I'll know that they are acceptable if the details and textures of these areas are not important to the over all image. Simply meter the brightest element where you want to preserve detail and set the exposure +3 or +4 EV. When adjusting various aspects of an image, I make sure that the dynamic range of finished result spans at least 16 through to 239.

These values work for me with my Sigma SD14, so you'll need to experiment to see how many EV you need to set your camera to get things to work for you.

[Ross]

Finally, I found out a interesting book "MASTERING EXPOSURE AND THE ZONE SYSTEM FOR DIGITAL PHOTOGRAPHERS" by Lee Veris.
In this book, this theme was mentioned clearly.

Ross

[arith]

Actually the rule "exposure for shadow, development for highlight" was the method that Adams employed to get a handle on the latitude, i.e. dynamic range, of the photographic materials that he was using and is actually all part of the Zone System developed by Ansel Adams and Fred Archer.

A key feature of using the Zone system is to maximize the utilization of the complete dynamic range available while preserving texture and detail within the central zones.

A google on "ansel adams zone system" yields over 35,000 hits and the best articles that I found are:

Zone System From Wikipedia

A Simplified Zone System By: Norman Koren

First, the Zone Systems breaks down the dynamic range of Black to White into 11 Zones ranging from Zone 0 through to Zone 10, and Zone 5 corresponds to middle grey. A key feature of the Zone System is the realization that Zones 0 and 1, Pure black and Near black with slight tonality but no texture, along with Zones 9 and 10, Slight tone without texture - glaring snow, Pure white light sources and specular reflections, are devoid of sufficient detail to offer any visible textures.

"exposure for shadow, development for highlight" comes from this Negative Film exposure procedure:

1. Visualize the darkest area of the subject in which detail is required, and place it on Zone III. The exposure for Zone III is important, because if the exposure is insufficient, the image may not have satisfactory shadow detail. If the shadow detail is not recorded at the time of exposure, nothing can be done to add it later.
2. Carefully meter the area visualized as Zone III and note the meter’s recommended exposure.
3. Adjust the recommended exposure so that the area is placed on Zone III rather than Zone V. To do this, use an exposure two stops less than the meter’s recommendation.

When employed for digital photography, just as with color reversal film, the normal procedure is to expose for the highlights, "Expose for the Right", and process for the shadows.

I have adapted the Zone System to my digital process flow with the following chart:

Where 0 EV corresponds to the digital value 128 and middle grey. I then break the dynamic range into 15 Zones and employ a power of 2 ascending and descending logarithmic scale that covers every possible value except for 0 ( Black ) and 255 ( White ), obviously values where data is potentially lost.

In use, I have my tools set to warn me of any pixel value that is below 16 or above 239. If elements of an image ever fall above or bellow these zones, I'll know that they are acceptable if the details and textures of these areas are not important to the over all image. Simply meter the brightest element where you want to preserve detail and set the exposure +3 or +4 EV. When adjusting various aspects of an image, I make sure that the dynamic range of finished result spans at least 16 through to 239.

These values work for me with my Sigma SD14, so you'll need to experiment to see how many EV you need to set your camera to get things to work for you.

You must be using a good system to see that; I can't see the blacks or whites, caused me to look at this again:
http://www.lagom.nl/lcd-test/white.php

and I can see all this and the black point ones as well. I think your test my be a tad hard.

[Donald]

Steaphany

I'm am very impressed with your adaptation and by your very clear and concise explanation of it.

I wasn't sure if the block of text underneath your reference to Koren was his work being quoted or your own text. I have assumed the latter, in which case my compliments for such an understandable explantion. Many starting out on the path and wishing to understand this, would do well to read this.

[Steaphany]

Thanks Donald,

Actually, my description was my own writing based upon details that came from the Wiki page.

[David deSousa]

Actually, my description was my own writing based upon details that came from the Wiki page.

Nevertheless, Steaphany, good job. This brings back old times.

D.

[Pedro]

Finally, I found out a interesting book "MASTERING EXPOSURE AND THE ZONE SYSTEM FOR DIGITAL PHOTOGRAPHERS" by Lee Veris.
In this book, this theme was mentioned clearly.

Ross

I think is worth to mention the original book "The Negative" by Ansel Adams himself, on which he explains the zone system and much more.

[Ross]

thanks a lot Pedro

Ross

[Sunray]

Thanks to Steaphany for the good explanation and to Steve for the monitor test charts.

bye
Robert

[brucehughw]

Hi,
I learned the zone system in the 80's, when I shot 35 mm and 4x5 sheet film. I liked it well enough at the time. With digital, I find that many scenes do not fill the entire dynamic range of an image, so it seems the zone system may not be necessary in such situations, except as a means to get a good initial exposure. Indeed, with the histogram (something we would have loved in the film days), we know immediately if we've over/under exposed a scene. My questions, to the forum, are: Do any of you use the system? Can you tell me a little about your experience with it? Can't we use histograms to tweak exposure, rather than the zone system?

thanks, Bruce

[Inkanyezi]

I have used the zone system extensively since the early sixties with black and white film.

An inherent property of black and white film is that you may extend the dynamic range rather much. The "normal" development will give you a range of about ten f-stops, which is sufficient for most photographic needs. There are two purposes of the zone system regarding dynamic range, either to expand or to shrink it. Negative film has a limited ability to register very low light values, while the other end is more open. Digital is the opposite, as there is an absolute value of exposure that should not be exceeded, unless you accept blown out highlights.

So a zone system for digital photography must by definition work the other way, from the brightest values. With some cameras it might be important to get it as right as possible, but modern sensors have a larger dynamic range than film did with normal development, as long as ISO is not raised. So in essence, we would not expose for the shadows, the old mantra doesn't work with electronic imaging.

The new mantra often is described with the acronym ETTR, expose to the right. I.e. you measure the brightest area where you want to discern structure and place it in your zone VIII. Then if you wish the whole scene to fall within your present dynamic range, you can also measure the other end of the scale and see if your ISO will hold detail in that zone. There is actually nothing you can do to extend the basic dynamic range, so most of us prefer to lose detail in the shadows when applicable, than burning out the highlights.

My routine when I want to "expose to the right" is to spot meter the brightest area where I want structure and expose for that value with +2 exposure compensation. Anything else then may fall wherever it falls. The exact compensation depends on the camera, so it has to be tried out. With some cameras you can compensate a bit more, with others less.

Mostly I use another approach, by setting highlight as well as low level warnings, which are live in my camera, and rely on its histogram to see that I use the dynamic range reasonably. When the dynamic range of the scene is narrower than that of the sensor, a higher ISO setting is possible without loss of image quality. The highlight warning will tell me where in the image there are areas that are close to burning out or burned out, while the low level warning will tell me where shadows are blocked out. At base ISO, where the camera has a great dynamic range, I am not eager to expose as far right as possible, as there is often leeway both sides of the scale. Image contrast is then adjusted in PP.

So, it is a bit like the zone system, but the other way around. You must take care not to burn your highlights, and you cannot always get good definition in the shade. There are however methods to extend dynamic range by combining different exposures. Some cameras also have greater dynamic range than average, so with the best sensors, dynamic range is in par with the black and white film. However when using the entire range, special tweaking of contrast may be necessary, similar to burn and dodge technique or by a process called tone mapping.

[brucehughw]

Thanks very much for sharing your approach. Do you tend to put faces (caucasian) in zone VI? This would seem to take care of exposure (assuming highlights are ok) and save time in PP. Any other "anchors," such as grass in zone IV, water in zone ?? that you usually use, or is your routine more ETTR with "R" being the brightest area you want to have structure? I don't think my D7000 lets me set low level warnings, but I do use the high warnings.

thanks again,

Bruce

[Inkanyezi]

I usually just eyeballl thei image in PP when I process it, and that may put faces in zone VI, but some features would rather touch zone VII, particularly in sunlight. Often I lift the curve a bit, which effectively is the same as increasing ISO, but without losing the rightmost anchor point.

D7000 has a large dynamic range at base ISO, so if you expose to the right, it should record rather deep shadows. But special treatment might be necessary to render a good pictorial effect with all the tones that the sensor captures. If you are at the edge with the highlights, you are almost certain to have the deep shadows as well.

[brucehughw]

Thank you. I'll keep this in mind in future shooting and PP.

Bruce