I’ve talked a lot about exposure when it comes to photography on this website. Much of my discussion focused primarily on how to set your camera properly for the lighting conditions you face as a photographer. And most of the time, through the settings you choose, accurate and appropriate exposure is achieved. There are occasions though, when you might need to “compensate” for tricky lighting situations. Times when your camera simply can’t do it on its own. And for these instances, exposure compensation is the answer.
In this post, I’m going to talk about many topics surrounding exposure compensation. I’ll discuss what it is and when you might need to use it. I’ll even offer some example photographs to demonstrate the differences between various compensation settings.
What Is Exposure Compensation?
The idea behind exposure compensation is to give the photographer control over lighting when the camera doesn’t do a good job at deciphering what the photographer’s intent is. Just a few evenings ago, I was attempting to take some photographs of the blue moon when I ran into difficulties – the pictures I was taking came out wildly over exposed. It wasn’t until I adjusted my camera’s exposure compensation that I began taking photos that were an accurate representation of what I was seeing with my eyes.
When setting exposure compensation on your DSLR camera, you’re generally given the ability to adjust exposure in one stop increments, with one third stop increments between them. When compensating exposure, all the camera is doing is overriding it’s previous selections relative to its new setting.
To better explain this concept, take a look at the photos below.
Canon T3i Exposure Compensation Setting
First, just to explain what you’re looking at, the exposure compensation setting is the scale that runs from -3 to 0 to +3. By holding down the small button towards the upper right that says “Av+-” and turning the dial right behind the shutter button back and forth, you can scroll up and down this scale.
In this first picture above, I simply turned the camera on and metered it. As you can see, in “Program” mode, my Canon T3i feels that, because of the given light, the shutter speed should be set at 1/25 of a second, the aperture should be open to F4.5 and the ISO should have a sensitivity of 400. Now, take a look at this next shot:
Canon T3i Exposure Compensation Setting Under Exposed by One Stop
For this picture, I merely adjusted the exposure compensation down one stop, to under expose any resulting photos. Look at the small tick mark beneath the “1” on the right side of the scale. If you’ll notice, the shutter speed has increased to 1/50 of a second, while aperture and ISO remained the same. This isn’t always the case. If I was under different lighting conditions, all these of these parameters may have changed, depending on what the camera thought was best.
Because I was purposefully underexposing this shot by one stop, the camera adjusted the shutter speed by one stop. Remember, a “stop” is simply a halving or doubling of light.
Canon T3i Exposure Compensation Setting Over Exposed by One Stop
In this final example, I set the exposure compensation on the camera to over expose by one stop. Again, the camera only adjusted shutter speed, and since I wanted more light to hit the sensor, it decreased shutter speed by one stop (increasing light), resulting in the shutter staying open twice as long it it would have if there was no compensation at all.
What About Priority Modes?
You may be wondering what happens if you adjust exposure compensation while shooting in priority modes. This is actually an important topic, because without being aware of its effects, exposure compensation can, and will, affect the sensitivity of shutter speed and aperture settings in ways you might not expect. It you’re in action or creative environments, this type of adjustment could be detrimental to your results.
Here’s the rule: If you’re in shutter priority mode and adjust exposure compensation down one stop, the camera will shrink your aperture by one stop, while maintaining your shutter speed. This change in setting will under expose your resulting photograph by one stop. Similarly, if you’re in aperture priority mode and adjust exposure compensation up one stop, the camera will slow down shutter speed by one stop, resulting in a photography that’s over exposed by one stop. It’s really that simple. By adjusting exposure compensation, all you’re doing is telling the camera to change the exposure of the photograph by altering a setting that isn’t “locked” in by a priority mode. You do need to be careful though, because, as I mentioned above, if you adjust exposure too far, your photographs might not come out as you expect them to.
Exposure Compensation Example Photos
For the examples below, I took seven photographs of the same flower. I began by adjusting the exposure compensation to the lowest possible setting and then continued up to the highest possible setting. As you’ll see below, the results are quite dramatic.
Bright flowers like this oftentimes cause cameras to over expose, so I wanted to view the output throughout the entire range. Also, it was interesting to watch the camera adjust settings as I metered for each shot. Below, I’ll list the metering settings:
Camera Settings Based On Exposure Compensation
I’ll list each group of settings in the order of exposure compensation, shutter speed, aperture size and ISO. While viewing the above photo, you can apply these setting from left to right. Also, while taking these pictures, I had the camera in “Program” mode.
Compensation, Shutter Speed, Aperture, ISO
-3, 1000, 11, 100
-2, 800, 10, 100
-1, 500, 9, 100
0, 400, 7.1, 100
+1, 250, 6.3, 100
+2, 200, 5.6, 200
+3, 200, 5.6, 400
In my opinion, while taking photos of bright flowers like this, it may be beneficial to set the exposure compensation down by one stop. I think more detail becomes apparent at that setting. If your photos are too dark, you can easily brighten them up to your liking in post-processing.
When To Take Advantage of Exposure Compensation
If you’ve ever tried to take photographs of subjects that contrasted greatly with their backgrounds, you’ve surely experienced your camera having difficulty correctly setting exposure for those situations. These types of settings may include objects of normal brightness that are situated against very bright backgrounds, such people, animals, trees or flowers against the bright blue sky. When you let the camera set for this type of shot, you’ll usually end up with a picture of a silhouette. The sky is simply too bright and the result is an underexposed photo of the subject.
Conversely, like I mentioned above, if you’ve ever attempted to take a picture of a very bright object that’s set against a dark background, such as the moon at night, the result will be a severely overexposed photo. The camera meters for all that darkness and the bright moon gets washed out in the process.
For both of these situations, utilizing the exposure compensation setting is a great solution. You can take multiple photographs at multiple settings and then choose the best ones while reviewing them on your computer.
Lastly, cameras also face challenges while taking photos of objects that vary greatly in shade. So, if you attempt to take a picture of a black and white yin and yang symbol, for instance, you’ll likely end up with either an under or over exposed photograph, depending on your background. It’ll take your manual input to gauge what “correct” is.
I hope you enjoyed this post on camera exposure compensation. If you did, please share the post with friends or those who you think might appreciate it. Also, if you have any comments or questions, please leave them in the space below. If you’d like to learn more photography tips and tutorials, check out the “Photography” link at the top of this page. Lastly, if you’d like to receive our posts by email, simply sign up for our newsletter and we’ll deliver every one of our posts directly to your inbox. Thanks!