Exposure compensation is one of those things many photographers never use. When you learn the basics, this is never the topic of conversation. It just sits in your camera settings without being addressed.
In this article we are going to look at what exposure compensation is, what it does and how it can help you. You’ll start wondering how you’ve managed to live without it so far.
What Is Exposure Compensation?
As we photograph a scene, our aim is to capture it with a correct exposure. We use the exposure triangle to capture the light in the best way possible. Everything works easily when you are using manual mode, but what about using automatic modes.
When you use different camera modes, your camera changes things for you. This is true for aperture priority mode, shutter priority mode, program mode and other scene modes. A change in one setting automatically changes the others and affects your camera’s exposure.
If you widen the aperture, the shutter speed will lengthen. If you shorten the shutter speed, the aperture will rise to compensate.
These modes aim to keep the exposure correct, while allowing for creative changes. You rely on your camera’s meter to read the scene correctly. Yet, if we want to add or subtract light, there isn’t much you can do.
This is where exposure compensation comes in. This setting or dial allows you to add or subtract up to three stops of light in your scene.
It does this without physically changing the shutter speed or aperture.
How to Use Exposure Compensation?
In certain situations, your camera may not read the light correctly. Or rather, not in the way you want it to. It will choose the wrong exposure settings. This, in turn, can over or underexpose the scene aggressively while it searches to find that 18% mid gray.
The sky can be a challenge for your camera, and so can very reflective surfaces. In short, your camera doesn’t record a scene exactly as you want it. Every digital camera has a way or correcting this.
Until the birth of the mirrorless systems, DSLR cameras didn’t see the point of having an external dial. Most DSLRs, like the Canon 7D Mark II, have the exposure compensation bar inside the Q menu.
Nowadays, digital cameras, such as the Fujifilm X-T10 have an exposure compensation dial. This makes it easier to change.
Otherwise it is in your camera settings, changeable via the menu and LCD screen or specific buttons.
What you will see is an Exposure Value Scale, or EV for short. Here you will see a bar with a 0 in the middle, minus numbers to the left and plus to the right.
If you need to decrease the brightness, the value needs to go left. If you need to raise the brightness, then the value needs to go right. Nice and simple; minus for a darker shot, plus for a lighter one.
NB: As we said before, the exposure compensation will only work outside of manual mode. Use it in aperture, shutter priority and other program modes.
- Option 1 – Press the Q button (Canon) on the back of your camera to open the settings panel. Navigate to the exposure value bar using the little joystick, and then use the gear wheel to raise or lower the exposure compensation.
- Option 2 – Find the button that has a black and white icon of a ‘plus’ and ‘minus’ symbol. Hold this in while you move the dial. Right adds a positive exposure value and left a negative exposure value.
Using the exposure compensation is easy and it works the same way on the dial as it does in-camera. The + sign brightens your scene and the – sign darkens it.
For example, if you are capturing a snow photography scene, you may find it’s overexposed. Overexposure means too much light, so to even it out, you need to darken the scene.
The dial on the exposure bar needs to move to a negative exposure value (-1, -2 or -3 for extremes).
The opposite works too if you find that the scene seems a little dark. Here you would brighten the scene by changing the exposure to a positive exposure value (+1, +2 or +3).
How Exposure Compensation Works?
Exposure compensation works by changing one or more of the exposure values that make up the image. If you are using aperture priority, you set the aperture that you want. The camera will automatically set the shutter speed.
If you are shooting using shutter speed priority, you choose the shutter speed. The aperture is what will change automatically. By adjusting the exposure compensation, you override your camera’s settings.
Here, we will try to explain what happens when you adjust exposure using exposure compensation in aperture priority mode.
Our original settings are as follows. These are what the camera tells us is correct for the best exposure. Here, we start with f/2 @ 1/500.
To reduce the exposure by one stop, we need to move the EV from 0 to -1. This increases our shutter speed from 1/500 to 1/1000, while the aperture stays the same.
To increase the shutter by one stop, we need to move the EV from 0 to +1. This decreases our shutter speed from 1/500 to 1/250, while the aperture stays at f/2.
There is one more aspect we need to look at. There is a way that you can use exposure compensation using the full manual mode. The only variable that can change is the ISO.
For this to work, you need to have ‘Auto ISO’ set. The ISO would change while keeping the shutter and aperture priority constant. I’m not sure if the ISO is something you might want to change, but it’s possible.
Exposure Compensation With Advanced Metering Systems
When a camera is metering the scene for the best exposure, it is looking for a middle grey, around 18%. Many modern cameras now have very sophisticated metering systems. These help to change the exposure of scenes automatically.
Some cameras have facial recognition software. Here, the camera meters on people’s skin tones as not to over expose them. Because of these advancements, less and less manual intervention is needed.
No matter how clever our cameras get, it is still great to know how to change these settings yourself.
Exposing to the Right
There is no such thing as a proper exposure. There is only an exposure that we want to achieve, based on what we are photographing. Sometimes we intentionally darken an image for specific purposes.
This guide suggests exposing the image as bright as you can, without blowing out the detail from the well lit areas. When you get home, you then darken the image during post-processing.
This gives us a much higher quality image as we are able to capture much more detail. By decreasing the EV back home, we are also able to decrease image noise while increasing the dynamic range.
There is one more area where exposure compensation might be of some use. Bracketing is an age old process of photographing the same scene multiple times. You do with with different exposure values.
This was helpful with photographers who used film to ensure they captured the shot at a correct light reading. Nowadays, we use bracketing in digital photography so we can blend them during the editing stage.
If you come across a scene with well lit areas and darker areas, bracketing helps to capture a correct, overall exposure. after blending the images together, you bring out detail from the darker areas while retaining them in the lighter ones.
The process is simple. The base image is taken with the exposure value at 0. Then you take two more images with corresponding minus and plus values. For example, an image at EV – 1 and then another image at EV +1.
This leaves you with three images. You can of course use EV -/+2 or EV -/+3, just make sure both numbers are the same. There is also nothing stopping you from capturing seven images in total, using every single stop on the exposure value scale.
For more information on this, look at our article on bracketing.
Convinced yet? Go out there and experiment with exposure compensation in you photos, from outdoor portraits to stunning landscapes. Feel free to show us your before and after shots in the comments below.