Exposure

[DanOstergren]

I have a habit of under exposing my images and then adjusting them in post to slightly intensify the highlights. I prefer lower key images and moody soft lighting with deep shadows, and I believe slightly under exposing (from what the meter on my camera usually tells me is "correct") lets me capture the image so that it's closer to what I am seeing for the final look in my head.

 

[GHK]

I think that high dynamic range, detail in the highlights and detail in the shadows is overrated in general

I don't think the problem is with dynamic range,

Neither do I, nor can I see what point is being made in the statement. The lower image has a dynamic range of 100%; it is just lacking in intermediate tones.

 

[tiaphoto]

I think its warranted to have underexposed or overexposed images if it fits your project. It's normally safer to get the best neutral exposure possible and then play around creatively in post. However, if your style is having overexposed photos, for example; then it should be fine to overexpose them a little. Plus when you over expose, its easier to pull information back into the image vs when underexposed.

 

[Tim Tucker]

It is incorrect to think in terms of a 'correct' exposure, but there is an optimum, or baseline exposure. Exposure is all about understanding how your media reacts to different levels of light, then using that to produce the results you want.

It is correct to think that there is a range of exposures, but incorrect to think that you can vary the exposure and correct the results. Every subject has a range of luminance, your whole image depends on there being a range of luminance that produces a variation in reaction on your chosen media in every exposure. If you vary the exposure you vary the reaction in your chosen media and it is a mistake to think that the tools at your disposal will allow you to make exposure 'A' look identical to exposure 'B'. They don't. In following a separate route to a result you invariably end up with a different result. It is in the understanding of how the media reacts to different levels of light and how varying this changes the results that is the heart of understanding exposure.

This is also key to understanding the Zone System. What Ansel Adams did was to first give you the optimal exposure and performance of film by establishing true film speed and optimum development. He then went on to show the effects of varying both the exposure and development of the film. Optimum is your baseline, it translates exposure to specific densities in the negative and from there to specific tones in the print. It must not be forgotten that the zones refer directly to tones in the print and not subject luminance. In giving you a baseline and a means of visualising it he also gave you the reference by which to view variations in exposure and development.

In B&W negative film you must first establish the true film speed (or crib Ansel's notes freely given at the back of his book "The Negative"). The film speed is the level of light needed to produce the first measurable change in density on the negative. Now on your negative the shadows produce very little change in the density of the film but your highlights being near maximum density produce maximum change in the density of the negative. So changes in development will have little to no effect where there is little development (shadows) but a big difference where there is a lot of development in the negative (highlights). So knowing where that baseline is is quite important with film. Film speeds on boxes and development times are a compromise. They allow speed and contrast at the expense of shadow detail and grain size. Basically you underexpose the film and over-develop, making the highlight areas more dense but producing little change in the shadows which remain under-exposed. This is what you need to understand with exposure and the Zone system, that you need to calibrate the threshold and the other end of the spectrum to finished tones in your print. It was never a guide to exposure but a visualisation and understanding of the whole process. This can be transferred to digital, understand and visualise your baseline and understand how the variations in exposure and processing change your result.

 

[Ysarex]

It is incorrect to think in terms of a 'correct' exposure, but there is an optimum, or baseline exposure. Exposure is all about understanding how your media reacts to different levels of light, then using that to produce the results you want.

How is optimum different from correct? You presented optimum exposure as a singular event precluding the existence of two or more different optimum exposures. But you say there is no correct exposure. Optimum sure sounds like correct to me. Is there a singular exposure that will produce either the best possible IQ and/or best realize the photographer's intention?

It is correct to think that there is a range of exposures, but incorrect to think that you can vary the exposure and correct the results. Every subject has a range of luminance, your whole image depends on there being a range of luminance that produces a variation in reaction on your chosen media in every exposure. If you vary the exposure you vary the reaction in your chosen media and it is a mistake to think that the tools at your disposal will allow you to make exposure 'A' look identical to exposure 'B'. They don't. In following a separate route to a result you invariably end up with a different result.

In one of the following two photos the camera sensor received 400% more exposure than in the other (check EXIF). 400% is two full stops. Can you point out in what ways they do not look identical?

Here are the two histograms for the above two photos:

It is in the understanding of how the media reacts to different levels of light and how varying this changes the results that is the heart of understanding exposure.

This is also key to understanding the Zone System. What Ansel Adams did was to first give you the optimal exposure and performance of film by establishing true film speed and optimum development. He then went on to show the effects of varying both the exposure and development of the film. Optimum is your baseline, it translates exposure to specific densities in the negative and from there to specific tones in the print. It must not be forgotten that the zones refer directly to tones in the print and not subject luminance. In giving you a baseline and a means of visualising it he also gave you the reference by which to view variations in exposure and development.

In B&W negative film you must first establish the true film speed (or crib Ansel's notes freely given at the back of his book "The Negative"). The film speed is the level of light needed to produce the first measurable change in density on the negative. Now on your negative the shadows produce very little change in the density of the film but your highlights being near maximum density produce maximum change in the density of the negative. So changes in development will have little to no effect where there is little development (shadows) but a big difference where there is a lot of development in the negative (highlights). So knowing where that baseline is is quite important with film. Film speeds on boxes and development times are a compromise. They allow speed and contrast at the expense of shadow detail and grain size. Basically you underexpose the film and over-develop, making the highlight areas more dense but producing little change in the shadows which remain under-exposed.

How can you underexpose if no correct exposure exists in the first place to underexpose from?

This is what you need to understand with exposure and the Zone system, that you need to calibrate the threshold and the other end of the spectrum to finished tones in your print. It was never a guide to exposure but a visualisation and understanding of the whole process. This can be transferred to digital, understand and visualise your baseline and understand how the variations in exposure and processing change your result.

The Zone System does not transfer to digital. Reason number 1: Digital has no corollary to the chemical development process. There is no N+ or N-- development option with digital. You could try and simulate that but for heaven's sake why. All that would do is unnecessarily cripple the digital process to no advantage. Dropping your SD card in a tank of HC-110 is a bad idea. Reason number 2: See those two photos above.

Joe

 

[Tim Tucker]

How is optimum different from correct? You presented optimum exposure as a singular event precluding the existence of two or more different optimum exposures. But you say there is no correct exposure. Optimum sure sounds like correct to me. Is there a singular exposure that will produce either the best possible IQ and/or best realize the photographer's intention?

Optimum exposure is a baseline reference.

In one of the following two photos the camera sensor received 400% more exposure than in the other (check EXIF). 400% is two full stops. Can you point out in what ways they do not look identical?

Sure they look identical and were processed to look the same. But this is not easily achieved and definately not possible in many circumstances (certainly not with film), so it's always better to approach exposure along the lines of giving a different exposure will produce a different result.

How can you underexpose if no correct exposure exists in the first place to underexpose from?

This is why you have the baseline reference, a point to which exposure is greater or less than. I think you take me too literally here and argue yourself in circles. How can you talk about under and over exposure if you don't select a baseline reference to which you make the comparison? There will be an optimum exposure, sometimes more than one, that will give the best IQ and colour rendition or the "best balance" between grain, contrast and DR. You then understand the effects of giving more or less exposure by comparing you baseline reference.

The Zone System does not transfer to digital. Reason number 1: Digital has no corollary to the chemical development process. There is no N+ or N-- development option with digital. You could try and simulate that but for heaven's sake why. All that would do is unnecessarily cripple the digital process to no advantage. Dropping your SD card in a tank of HC-110 is a bad idea. Reason number 2: See those two photos above.

Joe

I totally agree with you, the Zone System as in the zones themselves does not transfer to digital. But the idea that you study your medium and how it reacts to different levels of light is transferable, and to do that you need a reference to call 'normal', a scale by which you measure differences. That you use optimum IQ as your baseline does not mean that it's your goal in exposure. How do you express, "I want deeper and darker," if you don't have something it's deeper and darker than?
The whole concept then is that you learn how changing exposure produces different results, you study how to produce different results, not how to make different results look the same which I find a pointless exercise.

If I separate my last statement from the Zone System then my intended meaning may become clearer:

It was never a guide to exposure but a visualisation and understanding of the whole process. This can be transferred to digital, understand and visualise your baseline and understand how the variations in exposure and processing change your result.

 

[Ysarex]

How is optimum different from correct? You presented optimum exposure as a singular event precluding the existence of two or more different optimum exposures. But you say there is no correct exposure. Optimum sure sounds like correct to me. Is there a singular exposure that will produce either the best possible IQ and/or best realize the photographer's intention?

Optimum exposure is a baseline reference.

You didn't answer my question: Is there a singular exposure that will produce either the best possible IQ and/or best realize the photographer's intention?

In one of the following two photos the camera sensor received 400% more exposure than in the other (check EXIF). 400% is two full stops. Can you point out in what ways they do not look identical?

Sure they look identical and were processed to look the same. But this is not easily achieved and definately not possible in many circumstances (certainly not with film), so it's always better to approach exposure along the lines of giving a different exposure will produce a different result.

It was easy, however you're right it would have been impossible using film. But the OP has a digital camera and it is possible. You said it wasn't. Just making the point you're incorrect about that because it get's to how digital is different than film and the Zone System doesn't apply to digital.

I should have left the Zone System topic alone here and skipped the photo example, but it's so misunderstood and misapplied. Unfortunately it's a source here for further confusion.

How can you underexpose if no correct exposure exists in the first place to underexpose from?

This is why you have the baseline reference, a point to which exposure is greater or less than. I think you take me too literally here and argue yourself in circles.

I'm trying to help you unravel your circles.

How can you talk about under and over exposure if you don't select a baseline reference to which you make the comparison? There will be an optimum exposure, sometimes more than one, that will give the best IQ and colour rendition or the "best balance" between grain, contrast and DR. You then understand the effects of giving more or less exposure by comparing you baseline reference.

You just said there will sometimes be more than one optimum exposure. This is talking in circles; optimum is a superlative. A synonym for optimum is best. A superlative is by definition singular -- you can't have more than one optimum.

The Zone System does not transfer to digital. Reason number 1: Digital has no corollary to the chemical development process. There is no N+ or N-- development option with digital. You could try and simulate that but for heaven's sake why. All that would do is unnecessarily cripple the digital process to no advantage. Dropping your SD card in a tank of HC-110 is a bad idea. Reason number 2: See those two photos above.

Joe

I totally agree with you, the Zone System as in the zones themselves does not transfer to digital. But the idea that you study your medium and how it reacts to different levels of light is transferable, and to do that you need a reference to call 'normal', a scale by which you measure differences. That you use optimum IQ as your baseline does not mean that it's your goal in exposure. How do you express, "I want deeper and darker," if you don't have something it's deeper and darker than?

Good place to ask my question again that you didn't answer before: Is there a singular exposure that will produce either the best possible IQ and/or best realize the photographer's intention? You want deeper and darker, notice how my question made allowance for that: best possible IQ and/or best realize the photographer's intention.

SIMPLE: You see something you want to photograph. You have a goal to achieve the best result possible. This can include what you want to express like deeper and darker. It can also include the IQ characteristics that the discipline has identified as desirable. Any old exposure will do? Yes or no? If no, then isn't there a best, optimum, or correct exposure that will produce your goal?

Joe

The whole concept then is that you learn how changing exposure produces different results, you study how to produce different results, not how to make different results look the same which I find a pointless exercise.

If I separate my last statement from the Zone System then my intended meaning may become clearer:

It was never a guide to exposure but a visualisation and understanding of the whole process. This can be transferred to digital, understand and visualise your baseline and understand how the variations in exposure and processing change your result.

 

[Tim Tucker]

It was easy, however you're right it would have been impossible using film. But the OP has a digital camera and it is possible. You said it wasn't. Just making the point you're incorrect about that because it get's to how digital is different than film and the Zone System doesn't apply to digital.

I should have left the Zone System topic alone here and skipped the photo example, but it's so misunderstood and misapplied. Unfortunately it's a source here for further confusion.

But I so totally agree with you on this point. The Zone System in film is often misunderstood, and pointless when applied to digital.

To be clear because the original question was about exposure in digital and film: The Zone System for negative film was a method of visualisation, (in the days when you couldn't see the result straight after you pressed the shutter). It allowed you to see the process of exposure, development, and printing as a whole. It not only directly maps subject luminance to specific tones in the print, but allows you to visualise how changing exposure, development or both changes your result.

So what's wrong with applying the same philosophy to digital, in that we see the process as a whole and experiment with changing parts of the process to see how it changes the final image? By using a consistent approach to achieve the same result we can better understand how varying this changes the result, (as I keep saying and this is also a part of the ZS philosophy). I find it pointless in digital to use different routes to achieve the same result.

With your example I can't help thinking that you're using an exception to prove a point. It's a flat, static subject with limited DR and colour. You changed exposure by changing shutter speed and in most photography this does impact on the result.

It's immediately obvious, to anyone that tries, that the mapping of values such as skin tones to specific "zones" on your digital sensor's performance is a completely pointless exercise because digital editing allows you not only to change the values but also the relative relationship between values. Without these mid-tone placements digital exposure essentially becomes highlights and noise control and how this changes with ISO. You also have access to both view your exposure and considerable information about it which pushes visualisation to the effects of digital editing on the information which you see.

Do I have an optimum exposure that I use as my 'best IQ and colour rendition"? Yes, but don't assume that because I talk about the Zone System that I base this on the same model or that it is even a static model. All I'm saying is that in both film and digital you have to view the process as a whole (including the nature of light you're capturing), and have some consistency in your approach to see the effects of varying exposure.

I don't understand how your specific question with it's yes/no answer applies to digital or the point I tried to make. I certainly don't believe that an inconsistent approach of, "any exposure will do, I'll correct it later in post," gets you either the results you want or any sort of understanding of exposure.

 

[Gary A.]

The Zone System was brought up, (by me), as a methodology to understand metering and exposure. Learning how the meter works and how metering relates to exposure may significantly help the novice better grasp the basics of photography and how to apply those basics in their photographs.

 

[GHK]

[/QUOTE]

How is optimum different from correct?

Correct means correct - full stop.
The optimum value is a compromise; whilst not ideal, it is the best available combination in the relevant circumstances.
"What you gain on the roundabouts you lose on the swings" refers to such a compromise situation.
GHK

 

[jcdeboever]

The Zone System was brought up, (by me), as a methodology to understand metering and exposure. Learning how the meter works and how metering relates to exposure may significantly help the novice better grasp the basics of photography and how to apply those basics in their photographs.

Thank you Gary. It has been very helpful so far. I have had a lot of "ah ha" moments reading it. The book is very interesting. It is a hard read but I am taking it slow. I am getting a little confused when I read the above posts between the two trading jabs. I will stick with the book.

I will correct myself, not a hard read but very technical.

 

[Tim Tucker]

The Zone System was brought up, (by me), as a methodology to understand metering and exposure. Learning how the meter works and how metering relates to exposure may significantly help the novice better grasp the basics of photography and how to apply those basics in their photographs.

Thank you Gary. It has been very helpful so far. I have had a lot of "ah ha" moments reading it. The book is very interesting. It is a hard read but I am taking it slow. I am getting a little confused when I read the above posts between the two trading jabs. I will stick with the book.

I will correct myself, not a hard read but very technical.

I thoroughly recommend that book, and recommend you read both the full introduction and the full chapter on the Zone System, it will explain things far better than I can. But remember he is specifically discussing B&W negative material.

 

[pixmedic]

The OP has informed me that his question has been sufficiently answered to his satisfaction and requested that his thread be closed, and before people start the reports and the complaints about me closing a thread, I have always done that for anyone who wants their own thread closed.


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