Your camera is not perfect.
Don’t worry though, none of them are. The saving grace to this dilemma is the Exposure Compensation (sometimes called Exposure Bias) feature on DSLRs, smartphones, mirrorless cameras, drones and a lot of point and shoot cameras. It is a little button that looks like this.
The exposure compensation button works by forcing the camera to over expose or under expose, according to its current settings, by a set number of stops. Hence the symbol for it is the + and – signs.
Typically the range is -3 to +3 stops but some cameras will have a -5 to +5 range. Cameras are pretty similar in how the setting actives; simply press or hold down the button and then turn one of the camera dials. On phones you will typically tap the screen to set exposure then drag up or down to change it.
Your user manual explains exactly how your exposure compensation feature works.
How Handy is Exposure Compensation?
Exposure Compensation can be helpful when you know your camera is going to mess up or is already messing up. As explained in the Metering Modes post, your camera is not perfect and can only meter a limited area of the view. Plus, your camera has to make decisions about what’s important in the frame and try to make everything come out all average. But it makes mistakes.
We’ll use an image of a tugboat on Puget Sound from Seattle as an example of a challenging shot where exposure compensation helps.
Program mode, ISO 100, f/11, 1/500 – The camera is doing all the exposure calculations here:
Here’s the same shot over exposed by one stop.
Getting better. The tug is a little more visible.
Below are shots over exposed by two stops and then three stops.
I chose this image because these types of decisions come up all the time when shooting sunrise or sunset.
Now For Under Exposing
Swinging the other direction, we’ll under exposed by one, two and three stops.
We get more detail in the clouds lit by the setting sun, but we lose our main subject along the way.
As you can see, there is a big difference in exposures across a swath of seven stops of light (-3 to +3 stops). What is most pleasing to some, in this case, might not be pleasing to others.
How is it Useful?
The over/under exposure compensation is a quick way to correct your camera’s wrongheaded bias towards too harsh or too dull of light. In this example, the shot that was underexposed by one stop has a good chance of being salvaged and enhanced in a computer.
This quick setting can also help insure faces aren’t hidden in darkness by shadow when all around them is bright light. It’s better to blow out the details in the surroundings than leave a face too dark.
On Your Phone
To use exposure compensation on a phone, tap the screen and move your finger up or down to over or under exposure. It’s super easy.
Tomorrow we’ll cover Histograms!
Questions? Pop ’em like Pez in the comments section below. or email me at email@example.com.
Photography Basics – A 43 Day Adventure, and its companion 40 Photography Experiments, are series written by professional photographer Peter West Carey. The series are designed to unravel the mysteries of photography, helping you can take better pictures. Subscribe here to receive all the updates and bonus material. Your comments are always welcome.
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