Exposure compensation explanation/help

[The_Traveler]

EC is nothing more than a way of telling the camera (when in auto or semi-auto modes) that you want things a little brighter or darker than it thinks they should be. That's all

How does EC differ from adjusting ISO ?
From JoeW's description it's more related to manipulating the Dynamic Range capabilities.

Is it less noisy than ISO in particular situations ?
such as if at ISO 6400 and it's not quite enough, would upping EC be better than pushing ISO up ?

What TiredIron said is exactly on target.
You are adjusting the exposure to be different than what the camera suggests.
If you are shooting in any mode but manual, then the camera will adjust the shutter speed or aperture to comply with your selection of aperture or shutter speed.
Using EC tells teh camera to do something different - because you think the camera's decision won't be correct.

The noise in the image depend on the iso and sensor combination and the amount of light the sensor gets, so your EC can effect the noise but that is not your primary concern.

 

[Ysarex]

How does EC differ from adjusting ISO ?
From JoeW's description it's more related to manipulating the Dynamic Range capabilities.

Is it less noisy than ISO in particular situations ?
such as if at ISO 6400 and it's not quite enough, would upping EC be better than pushing ISO up ?

EC and ISO adjustment are very different. In both cases there's a tacit assumption that you're using the camera in an auto or semi-auto mode where the camera is able to alter shutter speed and/or f/stop.

A +EC adjustment then would cause the shutter speed to slow and/or the f/stop to open resulting in more exposure of the sensor = brightened image.
A -EC adjustment then would cause the shutter speed to speed up and/or the f/stop to close down resulting in less exposure of the sensor = darkened image.

When ISO is changed on a camera working in auto or semi-auto modes shutter speed and/or f/stop are altered but the ISO change also alters signal gain = constant image brightness maintained.

As a rule EC will alter shutter speed and/or f/stop to in fact alter exposure but depending on the camera make/model and design there's the possibility that EC could in fact alter ISO. My camera (well designed) won't permit that but others may. If the camera for example has reached a shutter speed limit and the lens is already wide open the camera (auto ISO enabled) could then use the ISO signal gain to brighten the image -- dangerous territory there as it can lead to twisted thinking. Next thing you know someone will suggest that ISO is in fact an exposure determinant.

If ISO 6400 wasn't quite enough you'd either raise ISO or use a -EC. Depending on the camera make/model you'll either get the same noise (but darker image from the -EC) or less noise from a further ISO increase.

Joe

 

[astroNikon]

Thanks, I understand that now in A/S/P modes

(Manual question) So looking at my d600 user book
It has a description for when in Manual mode

In mode M, exposure compensation affects only the exposure indicator; shutter speed and aperture do not change.

Thus am I to assume that it only changes the indicator but actually doesn't change anything when I'm in Manual ?

 

[Ysarex]

Thanks, I understand that now in A/S/P modes

(Manual question) So looking at my d600 user book
It has a description for when in Manual mode

In mode M, exposure compensation affects only the exposure indicator; shutter speed and aperture do not change.

Thus am I to assume that it only changes the indicator but actually doesn't change anything when I'm in Manual ?

You can only alter exposure in manual mode manually. Nikon is I believe unique in this: In manual mode Nikon applies the EC to the meter output so that adjusting shutter and/or f/stop to center the meter will in effect apply the EC. On my Fuji for example EC has no effect on anything when the camera is in manual.

Joe

 

[petrochemist]

I wouldn't worry about exp. comp., I never used it, I shoot full manual.

If you shoot manually you ARE effectively using exposure compensation as you're setting the camera for conditions other than 18% grey.

 

[SquarePeg]

I knew that I wanted at least 1/160 to freeze all but the fastest character movement, as well as to compensate for any camera movement when shooting at 200mm. I also knew that the lighting could change by as much as 9 stops almost instantly. Therefore, shutter priority seemed like the only sensible option, and because I needed to account for a bright, white costume, -1/3 -1/2 of EC was critical to the final exposure.

This is a very nice look into the thought process that you used and really helps to understand what you were doing and why. Very helpful to look at it with a specific example of real life circumstances.

 

[petrochemist]

How does EC differ from adjusting ISO ?

It depends on what mode you're in.
Unless you have auto ISO set, in Av it will adjust the shutter speed exactly by the amount set in EC, and in Sv it will adjust the aperture.

 

[Patrice]

I wouldn't worry about exp. comp., I never used it, I shoot full manual.

How is this a helpful answer to the original question?

 

[soufiej]

I guess I have a novice question. I have rarely used exposure compensation in my photography thus far. It's probably due to a lack of understanding. I understand the concept of E.C. tricking the camera into creating brighter or darker exposures for a specific scene.
What I don't understand is how this technique differs from just increasing or decreasing exposure in post processing? I started to believe they create the same results. If I'm wrong, please let me know so I can improve!
I have been taking portraits more frequently and I am just trying to understand the tools available to me.
Thanks!

"I rarely use manual mode. Just trying to understand A and S priority to its fullest."


Well, of course, the first best step to comprehending your camera's operation is to sit down with the manual and the camera and begin taking test shots based upon the manual's information. If you've not yet done that, that's where you should begin.

If you are not yet fully on line with the exposure triangle, read information which explains the three legged stool approach to proper exposure and relative exposure values. In basic physic class you may have learned three points define a plane which will always try to level itself. You can change the value of one point though the other two points will compensate in order to achieve balance. This is how exposure operates with your camera.

As noted, your "correct" exposure for any one scene is that set of values which will result in the least amount of over and under exposed areas within the frame. If you have not yet introduced yourself to your camera's histogram, find it and learn how to use it as your best tool for judging proper exposure for any given scene and metering mode.

Histogram - Wikipedia, the free encyclopedia



Your initial question regarding the adjustment of relative exposure values in post production depends heavily on how the histogram of the completed image appears. Once highlights are over exposed (blown out), it's very difficult to extract detail from those areas. Once the under exposure of blacks becomes too pronounced (they run off the left side of the histogram), extracting adequate detail from those areas becomes tedious and often fruitless work.

Relying on the histogram for proper exposure will provide you one more important tool in your kit. It is arguably the single most advantageous tool your digital camera provides.



When viewing the histogram, adjust the exposure compensation dial and notice the change in the look of the histogram. Then observe what exposure values have changed with your camera with each change in exposure compensation.

There are only three values to adjust for exposure so notice which values change with exposure compensation on your camera. Try this experiment with your camera set to one exposure value of, say, 100 and then repeat the experiment with the camera set to auto-ISO.

Realize you could have done the same by changing those same values manually but you are using a semi-automatic mode so the camera does the appropriate adjustments for you with the twist of a dial.

Before you leave this scene though, also change the metering value of your camera. Unless you are shooting a scene of monochromatic value entirely made up of one single brightness value, when you change the metering mode you will also change the look of the histogram.

Place the camera on the equivalent to spot metering, it's most tightly defined metering position, and move the aim of the lens around the scene as you observe the histogram. You'll see the shape of the histogram change as the metering of the system reads various levels of brightness or color. Half click your shutter release at various locations within the frame and you'll again notice how the camera's systems alter the exposure values to achieve a "proper" exposure given the data the system is taking in.

While you may not entirely grasp the data the histogram is providing at this point, this is how your camera operates. There is, in reality, no single correct exposure value for any scene. There are, in fact, numerous usable exposure values for any scene based upon the instructions you provide the camera.

It is your job as a photographer (shooting in something other than full automatic mode) to determine how best to adjust your camera to achieve in-camera what you see in your mind as the shot.




If you are now ready to explore aperture and shutter priority modes, try two experiments.

The first is for aperture and it involves you in a fixed position and a scene with three subjects in the frame. A street scene can work though what you require is a scene with three subjects; one very near field, one mid field and one a good distance from the camera/lens.

It's best to use a tripod if there's one available. This will allow you to lock the camera in one position as you make adjustments.

With the camera in this one position begin with the camera at its widest aperture setting and take a series of three shots. One shot will be with the camera focused on the closest object. Then one focused on the mid-distance object and finally on the farthest away object. Move the aperture value progressively towards its smallest setting and shoot the same scene in the same sequence after each change.

Afterwards, observe what the camera does in relation to depth of field and focus in each image.

Changing shutter speed is very much the same experiment though now you want moving objects which are all at roughly the same mid-way distance away from the lens. A busy intersection is good for this.

Begin with the longer shutter speeds and shoot an image of a car moving through the intersection. Gradually begin to increase the shutter speed as you continue to shoot images of cars moving through the frame. You will notice that motion is frozen after about 1/250 of a second shutter speed. Beneath that value motion is increasingly burred.



If in these two experiments you have not set your camera to auto ISO and have maintained the same metering setting throughout, you will also notice the relationships between aperture, shutter and ISO. There is only a small group of values which combine to make an acceptable exposure. Once you adjust one, the other two will attempt to find their own balance. If you've locked the camera into one ISO value, then the remaining two will compensate.

Looking at the images on your camera's LCD or on your computer monitor, pay attention to the histogram and the shot data for each image. This should give you a better understanding of how these three values work.

Hope that helps.

 

[PropilotBW]

I guess I have a novice question. I have rarely used exposure compensation in my photography thus far. It's probably due to a lack of understanding. I understand the concept of E.C. tricking the camera into creating brighter or darker exposures for a specific scene.
What I don't understand is how this technique differs from just increasing or decreasing exposure in post processing? I started to believe they create the same results. If I'm wrong, please let me know so I can improve!
I have been taking portraits more frequently and I am just trying to understand the tools available to me.
Thanks!

"I rarely use manual mode. Just trying to understand A and S priority to its fullest."


Well, of course, the first best step to comprehending your camera's operation is to sit down with the manual and the camera and begin taking test shots based upon the manual's information. If you've not yet done that, that's where you should begin.

If you are not yet fully on line with the exposure triangle, read information which explains the three legged stool approach to proper exposure and relative exposure values. In basic physic class you may have learned three points define a plane which will always try to level itself. You can change the value of one point though the other two points will compensate in order to achieve balance. This is how exposure operates with your camera.

As noted, your "correct" exposure for any one scene is that set of values which will result in the least amount of over and under exposed areas within the frame. If you have not yet introduced yourself to your camera's histogram, find it and learn how to use it as your best tool for judging proper exposure for any given scene and metering mode.

Histogram - Wikipedia, the free encyclopedia



Your initial question regarding the adjustment of relative exposure values in post production depends heavily on how the histogram of the completed image appears. Once highlights are over exposed (blown out), it's very difficult to extract detail from those areas. Once the under exposure of blacks becomes too pronounced (they run off the left side of the histogram), extracting adequate detail from those areas becomes tedious and often fruitless work.

Relying on the histogram for proper exposure will provide you one more important tool in your kit. It is arguably the single most advantageous tool your digital camera provides.



When viewing the histogram, adjust the exposure compensation dial and notice the change in the look of the histogram. Then observe what exposure values have changed with your camera with each change in exposure compensation.

There are only three values to adjust for exposure so notice which values change with exposure compensation on your camera. Try this experiment with your camera set to one exposure value of, say, 100 and then repeat the experiment with the camera set to auto-ISO.

Realize you could have done the same by changing those same values manually but you are using a semi-automatic mode so the camera does the appropriate adjustments for you with the twist of a dial.

Before you leave this scene though, also change the metering value of your camera. Unless you are shooting a scene of monochromatic value entirely made up of one single brightness value, when you change the metering mode you will also change the look of the histogram.

Place the camera on the equivalent to spot metering, it's most tightly defined metering position, and move the aim of the lens around the scene as you observe the histogram. You'll see the shape of the histogram change as the metering of the system reads various levels of brightness or color. Half click your shutter release at various locations within the frame and you'll again notice how the camera's systems alter the exposure values to achieve a "proper" exposure given the data the system is taking in.

While you may not entirely grasp the data the histogram is providing at this point, this is how your camera operates. There is, in reality, no single correct exposure value for any scene. There are, in fact, numerous usable exposure values for any scene based upon the instructions you provide the camera.

It is your job as a photographer (shooting in something other than full automatic mode) to determine how best to adjust your camera to achieve in-camera what you see in your mind as the shot.




If you are now ready to explore aperture and shutter priority modes, try two experiments.

The first is for aperture and it involves you in a fixed position and a scene with three subjects in the frame. A street scene can work though what you require is a scene with three subjects; one very near field, one mid field and one a good distance from the camera/lens.

It's best to use a tripod if there's one available. This will allow you to lock the camera in one position as you make adjustments.

With the camera in this one position begin with the camera at its widest aperture setting and take a series of three shots. One shot will be with the camera focused on the closest object. Then one focused on the mid-distance object and finally on the farthest away object. Move the aperture value progressively towards its smallest setting and shoot the same scene in the same sequence after each change.

Afterwards, observe what the camera does in relation to depth of field and focus in each image.

Changing shutter speed is very much the same experiment though now you want moving objects which are all at roughly the same mid-way distance away from the lens. A busy intersection is good for this.

Begin with the longer shutter speeds and shoot an image of a car moving through the intersection. Gradually begin to increase the shutter speed as you continue to shoot images of cars moving through the frame. You will notice that motion is frozen after about 1/250 of a second shutter speed. Beneath that value motion is increasingly burred.



If in these two experiments you have not set your camera to auto ISO and have maintained the same metering setting throughout, you will also notice the relationships between aperture, shutter and ISO. There is only a small group of values which combine to make an acceptable exposure. Once you adjust one, the other two will attempt to find their own balance. If you've locked the camera into one ISO value, then the remaining two will compensate.

Looking at the images on your camera's LCD or on your computer monitor, pay attention to the histogram and the shot data for each image. This should give you a better understanding of how these three values work.

Hope that helps.

Thanks for your reply. That was quite in depth and helpful information to try out.

 

[DB_Cro]

I wouldn't worry about exp. comp., I never used it, I shoot full manual.

If you shoot manually you ARE effectively using exposure compensation as you're setting the camera for conditions other than 18% grey.

True.

I wouldn't worry about exp. comp., I never used it, I shoot full manual.

How is this a helpful answer to the original question?

It's more help long term when you think about it then explaining what EC does since it's a crutch for people who
are scared of shooting in full manual. When you learn the exposure triangle and start shooting in manual you'll
wonder why you even bothered using EC.

I'm sure some will be offended by this but.. I was too few years ago.

Going one step back, some people get offended when you suggest they stop using the "running man" or "portrait" mode
on their cameras and try A or S. Basically the same thing.

 

[tirediron]

It's more help long term when you think about it then explaining what EC does since it's a crutch for people who
are scared of shooting in full manual. When you learn the exposure triangle and start shooting in manual you'll
wonder why you even bothered using EC.

I'm sure some will be offended by this but.. I was too few years ago.

Going one step back, some people get offended when you suggest they stop using the "running man" or "portrait" mode
on their cameras and try A or S. Basically the same thing.

What are you smoking, and why haven't you shared with the rest of us? "Exposure compensation is a "crutch" for people scared of shooting on full manual"???? In what universe? I'm not insulted, nor offended, but I am aboslutely astonished that someone could say with [I assume] a straight face, something so utterly ridiculous. Exposure compensation is a tool which has specific uses and has been on cameras virtually since the advent of automated exposure.

Shooting in manual has its place, but so do AP/Av and SP/Tv. Program is useful as well. I'm glad that you are so much more accomplished than am I, and that you're able to adjust for every possible nuance of a situation, regardless of how dynamic it is. I certainly can't do that, but I only picked up a camera 35 years ago (give or take).

You disagreed with my earlier assertion on this topic - and while you're free to express your opinion by using 'Disagree', I would be most intereted in hearing you articulate exactly why you feel that your position is the only valid one. Can I also assume that you use only manual focus since AF would be an equally amateur crutch....

 

[DB_Cro]

Since these semi-auto modes sometimes don't give the desired results, EC is there to help, i.e. a crutch.
It's exactly that, not an opinion, purely objective. It's a helping tool, like, again, a crutch.
More to do with understanding English (which is not my native language) then photography.

If you use full manual mode, you don't need (or have) it, since you have full control over the exposure, so why not just
learn to manually expose in every situation and not bother learning to use EC? Only benefit of using EC over manual is
not being able to react fast enough in manual and/or not being skilled enough to guess the settings when you walk into
the room.

Using these semi-auto modes you'll be stuck at that level of understanding available light and proper exposure forever.
Focusing is a completely different subject and you know it is.

 

[tirediron]

Since these semi-auto modes sometimes don't give the desired results, EC is there to help, i.e. a crutch.
It's exactly that, not an opinion, purely objective. It's a helping tool, like, again, a crutch.
More to do with understanding English (which is not my native language) then photography.

First and foremost, my apologies; I hadn't actully looked at your location and since your "written" English is better than that of many native English speakers, I had assumed, that to be the case. Therefore, I withdraw my objection to your use of the word 'crutch'.

If you use full manual mode, you don't need (or have) it, since you have full control over the exposure, so why not just learn to manually expose in every situation and not bother learning to use EC? Only benefit of using EC over manual is not being able to react fast enough in manual and/or not being skilled enough to guess the settings when you walk into the room.

I am perfectly willing to put my skill, experience and knowlege up against almost anyone here, and I know that there are situations in which the use of EC is appropriate. Again, in my earlier post, I cited the use of AP in combination with a specific set of conditions. Please explain to me why you feel that it would have been done in manual!

Using these semi-auto modes you'll be stuck at that level of understanding available light and proper exposure forever. Focusing is a completely different subject and you know it is.

Again, I would like to think that my understanding of light, exposure and most other basic photographic theory is fairly good; I seem to be able to use these modes, as well as manual without too many issues. As far as focusing, why do you feel that using automated focusing is so vastly different than automated exposure?

 

[petrochemist]

There are times when the semi auto modes don't give the desired results, but they are fairly rare, and experienced photographers will usually known in advance, and switch to manual. There are very few occasions where both the shutter speed & aperture are critical and must be precise values.
EC allows the photographer to access the desired result compared to the default average 18% and control the camera to get the results he wants. It's no more of a crutch than the light meter is.

Automatic focusing may be a different subject, but the camera doesn't always get it right, and there are times when you need to override it to get the results you want. I myself would consider it more of a crutch than EC. I freely use it as well, but know that under certain conditions it's better to just switch it off. The similarities seem fairly obvious to me.