What I was saying is weird was your attributing the meaning that you did to your construction in this phrase: "Density increases with exposure". Not the fact that we have reversal and negative films.
What I was saying is weird was your attributing the meaning that you did to your construction in this phrase: "Density increases with exposure". Not the fact that we have reversal and negative films.
While underexposure and overexposure will make an image lighter or darker, to ensure the best possible signal to noise ratio and maximum dynamic range, optimal exposure is about recording as much sensor exposure as possible without blowing any important highlights (or compromising DOF/motion blur etc.) and can easily result in an initially too light or too dark image.
Clearly, this RAW image initially appears too dark, but was it underexposed?
Not if you wanted the highlight detail intact it wasn't...
@TechTalk has written:Producing the desired final image requires accurate exposure for the lighting conditions combined with the required signal or image processing. Optimum exposure is one component of the choices and compromises made by the photographer to balance light, exposure, and processing for the best achievable result.
Sure, but image brightness and exposure should be considered and handled independently, they are not the same thing.
No argument here. It's always a balancing act to achieve the desired result or to make the compromises which best represent your intent.
What I was saying is weird was your attributing the meaning that you did to your construction in this phrase: "Density increases with exposure". Not the fact that we have reversal and negative films.
Thanks. I already clarified my intention in an earlier post above: "The implication which was intended is that exposure density is directly related to the amount received (how much or how little) by any type of film."
@TechTalk has written:[quote="@ErikWithaK"]
The term “overexposure” really ought to only be applied to an excess of sensor exposure (Scene lighting + Aperture + Shutter Speed) resulting in unintended clipped highlight detail at base ISO. While undesirable highlight detail clipping can also be caused by an excess of pre-ADC ISO brightening being applied to a (non-clipped) base sensor exposure, this needs to be considered independently, IMO.
While “optimal” exposure could be considered as the brightest important highlight detail being recorded just below clipping at base ISO, with significant exposure below that being considered “underexposed”, if there isn’t enough available light to fully saturate the sensor, I would also consider setting the maximum amount of sensor exposure possible without compromising the necessary SS/Aperture settings required for avoiding DOF and/or motion blur issues to be “optimal” exposure in that situation. Using a lower than optimal exposure here with an unnecessarily high ISO setting should also be considered “underexposure” in my book. Whether the resulting mid tones initially appearing too bright or too dark have nothing to do with being optimally exposed (at least for the RAW shooter). The jpeg shooter should also try to maximize sensor exposure when possible, but sometimes compromises will have to be made if an optimal SOOC jpeg is of primary importance.
Quoted message:Over exposure produces images which are lighter than desired in the final image and is the result of capturing more light than required. Under exposure produces images which are darker than desired in the final image and is the result of not capturing enough light to produce the desired final image. Over and under exposure can occur regardless of the ISO / EI (exposure index) chosen to produce the desired final image.
While underexposure and overexposure will make an image lighter or darker, to ensure the best possible signal to noise ratio and maximum dynamic range, optimal exposure is about recording as much sensor exposure as possible without blowing any important highlights (or compromising DOF/motion blur etc.) and can easily result in an initially too light or too dark image.
Clearly, this RAW image initially appears too dark, but was it underexposed?
If you could have used a slower shutter speed and/or wider aperture and still met your dof and motion blur requirements without clipping important highlights, then yes, it is under exposed*. Otherwise no.
To maximise the quality of the raw data, at least with regard to minimising visible noise, you need to get as much light as possible onto the sensor while the shutter is open within your dof and blur constraints without clipping important highlights.
* exposure - amount of light striking the sensor per unit area while the shutter is open.
Not if you wanted the highlight detail intact it wasn't...
Quoted message:Producing the desired final image requires accurate exposure for the lighting conditions combined with the required signal or image processing. Optimum exposure is one component of the choices and compromises made by the photographer to balance light, exposure, and processing for the best achievable result.
Sure, but image brightness and exposure should be considered and handled independently, they are not the same thing.
[quote="@ErikWithaK"]
[quote="@TechTalk"]
[quote="@ErikWithaK"]The term “overexposure” really ought to only be applied to an excess of sensor exposure (Scene lighting + Aperture + Shutter Speed) resulting in unintended clipped highlight detail at base ISO. While undesirable highlight detail clipping can also be caused by an excess of pre-ADC ISO brightening being applied to a (non-clipped) base sensor exposure, this needs to be considered independently, IMO.
While “optimal” exposure could be considered as the brightest important highlight detail being recorded just below clipping at base ISO, with significant exposure below that being considered “underexposed”, if there isn’t enough available light to fully saturate the sensor, I would also consider setting the maximum amount of sensor exposure possible without compromising the necessary SS/Aperture settings required for avoiding DOF and/or motion blur issues to be “optimal” exposure in that situation. Using a lower than optimal exposure here with an unnecessarily high ISO setting should also be considered “underexposure” in my book. Whether the resulting mid tones initially appearing too bright or too dark have nothing to do with being optimally exposed (at least for the RAW shooter). The jpeg shooter should also try to maximize sensor exposure when possible, but sometimes compromises will have to be made if an optimal SOOC jpeg is of primary importance.
Over exposure produces images which are lighter than desired in the final image and is the result of capturing more light than required. Under exposure produces images which are darker than desired in the final image and is the result of not capturing enough light to produce the desired final image. Over and under exposure can occur regardless of the ISO / EI (exposure index) chosen to produce the desired final image.
While underexposure and overexposure will make an image lighter or darker, to ensure the best possible signal to noise ratio and maximum dynamic range, optimal exposure is about recording as much sensor exposure as possible without blowing any important highlights (or compromising DOF/motion blur etc.) and can easily result in an initially too light or too dark image.Clearly, this RAW image initially appears too dark, but was it underexposed?
Not if you wanted the highlight detail intact it wasn't...
If you could have used a slower shutter speed and/or wider aperture and still met your dof and motion blur requirements without clipping important highlights, then yes, it is under exposed*. Otherwise no.
Shot as base ISO to maximize DR, with highlights recorded just below clipping (-4EV, resulting in ISO 200 instead of ISO 3200 with no exposure compromise).
To maximise the quality of the raw data, at least with regard to minimising visible noise, you need to get as much light as possible onto the sensor within your dof and blur constraints without clipping important highlights.
* exposure - amount of light striking the sensor per unit area while the shutter is open.
Yes.
Quoted message:Producing the desired final image requires accurate exposure for the lighting conditions combined with the required signal or image processing. Optimum exposure is one component of the choices and compromises made by the photographer to balance light, exposure, and processing for the best achievable result.
Sure, but image brightness and exposure should be considered and handled independently, they are not the same thing.
I would have left the iso at 3200 and set the final image lightness in post.
For many cameras raising iso for a given exposure* reduces read noise.
By lowering the iso you probably increased the read noise.
It depends on which is more important, read noise or dynamic range.
I would have left the iso at 3200 and set the final image lightness in post.
For many cameras raising iso for a given exposure* reduces read noise.
ISO 3200 would have nuked the highlights (4 stops beyond clipping). This was an extreme scene with ridiculous dynamic range. This was as much a technical ISO invariance exercise as a an attempt to take decent shot. The highlights where recorded just below clipping at base ISO
By lowering the iso you probably increased the read noise.
.Yes, but just a bit,
It depends on which is more important, read noise or dynamic range.
In this case there was no choice, any increase in ISO would have necessitated a reduction in sensor exposure (which would be worse).
I must say, the old DPR forums were more intuitive to use than here. This will take some getting used to.
When someone says an image is over or under exposed they are in effect just guessing as to whether the best exposure was used or not by the photographer unless they are certain of the photographer's artistic intentions.
This is not true for film, where an examination of the developed film will show whether it was exposed correctly for the development process used.
What they really mean when they describe an image as over/under exposed is that they see the image as being too light or too dark.
As noted above, with slide film that uses standardized processing (i.e. E-6), exposure does determine image lightness. However, with some slide films it may be desirable to overexpose the film slightly to get more pleasing colors (lightness).
Fortunately, there is no switch in your car that reverses the function of the accelerator and brake pedal.
A vacuum leak in the brake booster will result in the brake pedal causing the engine to accelerate. Ask me how I know.
@DannoB has written:I would have left the iso at 3200 and set the final image lightness in post.
For many cameras raising iso for a given exposure* reduces read noise.ISO 3200 would have nuked the highlights (4 stops beyond clipping). This was an extreme scene with ridiculous dynamic range. This was as much a technical ISO invariance exercise as a an attempt to take decent shot. The highlights where recorded just below clipping at base ISO
@DannoB has written:By lowering the iso you probably increased the read noise.
.Yes, but just a bit,
@DannoB has written:It depends on which is more important, read noise or dynamic range.
In this case there was no choice, any increase in ISO would have necessitated a reduction in sensor exposure (which would be worse).
I must say, the old DPR forums were more intuitive to use than here. This will take some getting used to.
Ok, it wasn't clear to me if iso 3200 was actually set or not. I assumed it was.
@DannoB has written:When someone says an image is over or under exposed they are in effect just guessing as to whether the best exposure was used or not by the photographer unless they are certain of the photographer's artistic intentions.
This is not true for film, where an examination of the developed film will show whether it was exposed correctly for the development process used.
Quoted message:What they really mean when they describe an image as over/under exposed is that they see the image as being too light or too dark.
As noted above, with slide film that uses standardized processing (i.e. E-6), exposure does determine image lightness. However, with some slide films it may be desirable to overexpose the film slightly to get more pleasing colors (lightness).
I have never used film so I wouldn't know.
From your reply I assume you agree what I posted is true for digital.
@TechTalk has written:Fortunately, there is no switch in your car that reverses the function of the accelerator and brake pedal.
A vacuum leak in the brake booster will result in the brake pedal causing the engine to accelerate. Ask me how I know.
I'm glad you're still around to relate that to us!
@ErikWithaK has written: @DannoB has written:I would have left the iso at 3200 and set the final image lightness in post.
For many cameras raising iso for a given exposure* reduces read noise.ISO 3200 would have nuked the highlights (4 stops beyond clipping). This was an extreme scene with ridiculous dynamic range. This was as much a technical ISO invariance exercise as a an attempt to take decent shot. The highlights where recorded just below clipping at base ISO
@DannoB has written:By lowering the iso you probably increased the read noise.
.Yes, but just a bit,
@DannoB has written:It depends on which is more important, read noise or dynamic range.
In this case there was no choice, any increase in ISO would have necessitated a reduction in sensor exposure (which would be worse).
I must say, the old DPR forums were more intuitive to use than here. This will take some getting used to.
Ok, it wasn't clear to me if iso 3200 was actually set or not. I assumed it was.
I generally shoot with Auto-ISO with exposure compensation, had I not dialed it way back, the ISO would have been at 3200 and the highlights would be toast.
I generally shoot with Auto-ISO with exposure compensation, had I not dialed it way back, the ISO would have been at 3200 and the highlights would be toast.
I also prefer Auto ISO as described in my "Why are my photos noisy?" thread on this forum.
Anyway, earlier you asked if your posted raw file was under exposed.
I replied under what circumstances I would see it as under exposed* or not.
* exposure - amount of light striking the sensor per unit area while the shutter is open.
an examination of the developed film will show whether it was exposed correctly for the development process used.
For the same processing, I expose differently for optical print and for scanning. The factor here is what I'm going to do with the film.
I have never used film so I wouldn't know.
Probably best to specify then, since film photography remains popular (and at the rate digital camera sales are going, might become the dominant form of photography again).
From your reply I assume you agree what I posted is true for digital.
I can't decide, and having always thought DPR's stuck record rule was a good one, I'm not inclined to argue. There are others who will do that anyway.
I do agree that some photographers (perhaps many photographers) use over- and under-exposure in a way that is outdated (and wasn't necessarily true in the film days). I don't think it's useful to jump all over people (especially in a beginners forum) when they use those terms in place of lightness. Many photographers shoot jpg, and do indeed use jpg as their primary lightness control. This has its compromises on image quality but on a sunny day it makes little difference in apparent picture quality (and by apparent I mean what you see without getting down to the pixel level).
Educate them, yes. Pounce on them DPR-style with WHAT THE HELL DO YOU THINK EXPOSURE MEANS???, no.
As I see it, exposure in digital is a more nebulous concept, and optimal exposure is almost impossible to define, at least without resorting to a large number of variables that make it nearly meaningless anyway. With film, the answer to "What is the optimum exposure for this scene?" has a very narrow range of answers. Under the same circumstances with digital, the true answer is "It depends".
I do think the concept of "nailing the exposure" doesn't have the importance in digital photography than it did in film photography. That is the beauty of digital, you can have a way-less-than-optimal exposure and still get a very usable image. The gap with film is much narrower. Part of the reason I prefer it.
For the same processing, I expose differently for optical print and for scanning. The factor here is what I'm going to do with the film.
What if you're going to do both?
@DannoB has written:I have never used film so I wouldn't know.
Probably best to specify then, since film photography remains popular (and at the rate digital camera sales are going, might become the dominant form of photography again).
I am assuming the D in DPRevived stands for Digital so there is no need for me to specify unless i specifically refer to film.
If what you predict eventuates then perhaps this site's domain name could be changed to FPRevived.com :-)
Quoted message:From your reply I assume you agree what I posted is true for digital.
I can't decide, and having always thought DPR's stuck record rule was a good one, I'm not inclined to argue. There are others who will do that anyway.
I do agree that some photographers (perhaps many photographers) use over- and under-exposure in a way that is outdated (and wasn't necessarily true in the film days). I don't think it's useful to jump all over people (especially in a beginners forum) when they use those terms in place of lightness. Many photographers shoot jpg, and do indeed use jpg as their primary lightness control. This has its compromises on image quality but on a sunny day it makes little difference in apparent picture quality (and by apparent I mean what you see without getting down to the pixel level).
Educate them, yes. Pounce on them DPR-style with WHAT THE HELL DO YOU THINK EXPOSURE MEANS???, no.
As I see it, exposure in digital is a more nebulous concept,
For me the definition of exposure is very clear and simple. Exposure is the amount of light striking the sensor per unit area while the shutter is open.
and optimal exposure is almost impossible to define,
For me that is simple and clear as well but everyone will have a different definition for optimal exposure according to their needs and goals.
For me, optimal exposure is the maximum exposure (as defined above) within dof and motion blur requirements without clipping important highlights.
at least without resorting to a large number of variables that make it nearly meaningless anyway. With film, the answer to "What is the optimum exposure for this scene?" has a very narrow range of answers. Under the same circumstances with digital, the true answer is "It depends".
I do think the concept of "nailing the exposure" doesn't have the importance in digital photography than it did in film photography. That is the beauty of digital, you can have a way-less-than-optimal exposure and still get a very usable image. The gap with film is much narrower. Part of the reason I prefer it.