What Is Exposure Compensation?
Exposure compensation, what is it and what does it do?
There will be times when you need to use exposure compensation to correct a badly exposed image.
So you ask just what is exposure compensation.
In essence, it’s when the exposure your camera choses as the optimum exposure is wrong.
Instead it will be either too bright or too dark.
After taking a photo you should check it on the back screen.
Check the histogram as it will indicate how good or otherwise the exposure is.
If it’s too bright, or too dark, you can apply exposure compensation, and shoot again.
Provided you’ve applied the correct amount, you should have a better photograph.
How your camera decides the exposure
When you’re going to take a photograph your camera takes a reading from the light reflected from the scene it’s about to capture.
This may be a landscape, a still life, a portrait, or whatever.
From this it decides how dark or light the photograph should be.
If it’s a very bright scene, like a snow scene, it will take a photo it darker than should be.
When you take a photo of a dark scene like a night scene, it will brighten it.
Digital cameras like mid tones
Digital cameras are programmed to render photographs as mid-tones.
The ideal photograph will look it’s best if the tones through the image are balanced between bright and dark.
When the camera is presented with such a scene it should do a pretty good job with it.
When the camera is facing a scene that is mostly dark, or bright, it won’t do as well.
It will try and display as much as possible in a mid tone, as close as possible to eighteen percent grey.
This is a mid tone, a cameras preferred one.
Digital cameras are built to render every photo as close as possible to mid grey.
If there’s a good spread of different tones throughout the image it should be quite accurate.
Otherwise it will try to compensate.
When it’s time to apply exposure compensation
That’s when it’s time to intervene.
Cameras that are equipped with the feature usually have a method of applying it.
Normally there’s a dial visible on the camera’s screen and is moved up or down by a dial or button.
Generally there’s two, or more, stops of positive, and the same of negative exposure compensation available, but sometimes.
Newer cameras tend to have more as the technology of digital cameras evolves.
All but basic cameras have exposure compensation which will allow you to correct the cameras interpretation of a subject.
It’s different in Manual shooting mode
Where it is present, it’s only useable in Aperture Priority, Shutter Priority and Program modes.
It’s not available in Manual or any preset scene modes that a camera might have.
When shooting in Manual, you have chose all the settings yourself.
If you get it wrong, it’s not the cameras fault, it’s yours.
On some basic point and shoot cameras there’s only preset scene modes available so exposure compensation is not available.
Applying exposure compensation
We’ll take a look at how this works on cameras which have the feature.
I’ve taken some photographs where exposure compensation has been used.
We’ll have a look at those and see how and what happened.
Sometimes it’s easy to just pick up your camera and take a shot without checking the settings.
That’s what happened here.
We don’t get very much snow in Ireland, and when we did early in 2018 I just shot without checking.
The resulting shot was blue.
Then I adjusted the settings by adding positive exposure compensation and got a much more realistic image.
The scene was very bright so the camera reckoned that it should be darker so it recorded it as a mid tone.
There’s an abundance of photographs with blue or grey snow where this has happened.
Positive and negative exposure
Next we’ll look at three photographs which I purposely took with three different levels of exposure compensation to illustrate the concept.
The first one is as the computer judged it without any adjustment.
With a variety of different shades, some bright, some dark and others in the middle, it did a good job.
This is the type of scene that a camera will perform well with.
The second photo was taken with one stop of positive exposure compensation added.
This in effect slowed the shutter and let in an extra stop of light, making the image brighter.
It clearly looks too bright with some of the colours almost washed out.
By comparison the shot with the cameras calculation is much better looking.
To illustrate even more I took a third shot, this time with a stop of negative exposure compensation applied.
This forced the camera to take a faster shot, letting in less light.
It’s a darker shot than the others, and while it’s not as nice as the first, I think it looks better than the over exposed shot.
While the correct exposure is definable, you might prefer photographs that are a little over or under exposed.
The world would be a dull place if everyone had similar tastes.
The next three photos take the illustration even farther.
It started with another shot with the exposure chosen by the camera.
The background here was on the light side so this was a little under exposed, but it’s perfect to show what exposure compensation is all about.
For the second of these photographs I added two stops of positive exposure compensation.
It’s clearly too much.
While the first shot needed some adjustment, two stops is too much, leaving the shot too bright.
Exposure compensation can be applied in half or thirds of a stop.
One full stop, or a third each side of that would have sufficed here.
Clearly the third image with two full stops of negative exposure compensation applied is very much under exposed.
There’s little more than a silhouette to be seen in a photo which is extremely dark.
It’s a horrible photo but it does illustrate the difference incorrect exposure can make.
Correct exposure compensation
It’s an important consideration when taking photographs because we want them to be as good as possible.
What looks like a disappointing photo can be corrected so easily by applying exposure compensation and shooting a second time.
When photographs were taken on film cameras one had to wait until they were developed to check them.
It was too late to fix them if they were incorrectly exposed then, and the moment was gone.
That’s not the way with digital photography, just check it right after you take it, and fix it if it’s not correct.
On most occasions the camera will get the exposure correct, or very close to it, but when it doesn’t exposure compensation will.
It does take a bit of time and experience to know when to use it.
Some people will prefer a photograph that is a little over or under exposed and that’s fine.
However as always it’s better to know rules and chose to break them, than break them because you don’t know them.