Raise a hand if you spend a lot of your time in your camera’s auto modes, Program, Shutter or Aperture Priority, or even Scene Modes. Keep your hand raised if you would like to shoot manually, but either A, Do not have enough time to set it up, or B, still a little perplexed by manual exposure. If you have answered yes to either of these questions, perhaps it's time to look at exposure compensation, the easy way into manual exposure.
What Is Exposure Compensation?
Well, put simply it allows you to incrementally adjust the camera’s exposure around the default reading that the meter is giving. Nearly all DSLRs and advanced compacts have this feature to some extent. Some are limited to changes of 1/2 a stop or 1 complete stop at a time, professional level cameras will allow you to define the amount of compensation from 1/3 of a stop to 1 stop and make changes of up to 5 stops either way.
How Does It Work?
Let’s assume you are shooting in aperture priority. You have chosen your aperture based on the subject matter but find that your image is constantly dark. By adding +1/2 or +1 stops via the exposure compensation on your camera you will lighten the image overall. When in aperture priority, because you want the aperture to remain the same, the camera will use a slower shutter speed to compensate.
Conversely, in shutter priority mode, the camera will open the aperture, allowing more light to reach the sensor (or film). The reverse is true if you are finding your image is too light, dialing in a minus exposure compensation number will darken your image incrementally.
So what happens if I use a program mode I hear you cry? Well, different manufacturers have different ways of dealing with this but generally, they will compensate using a combination of shutter and aperture. It can also be used in manual mode, here, the camera’s meter indicator will show the correct exposure as being the compensated exposure.
So, Why Should I Use It?
There are several reasons, but they all stem from the camera meter’s ability to determine exposure. Today’s camera meters are fantastically accurate for most things, but they can still get it wrong. A classic example is a snow because the camera’s meter expects a scene to be the electronic equivalent of a mid-grey, when you throw in huge amounts of white, it underexposes. Dialing in a plus compensation will lighten the image and whiten your snow to a more natural appearance.
Another classic example is birds or aircraft in flight. Even the best exposure meters will generally expose the sky leaving the bird or plane dark in comparison. Again dialing some plus exposure will lighten up your subject although possibly at the expense of a washed-out sky. A typical example that may overexpose is a forested landscape; the darkness of the trees can very often trip up a meter. Here, using minus compensation will help correct exposure.
How Much Compensation Should I Use?
There is no firm answer to that, it will vary from shot to shot, scene to scene. One thing I would recommend though is to learn to NOT trust your camera’s preview screen. They should only be used as a very rough guide to exposure and composure, no more. Perhaps the best way of checking you have the correct amount of exposure compensation is to use your camera’s histograms. Learning how a histogram works will make both exposure compensation and indeed manual exposure become second nature with a little practice.
Lastly, how do you find the exposure compensation setting on your camera? Well, the manual is your friend here, different cameras have different systems from a simple dial on the camera top plate, through a button/dial combination to being buried in a menu selection. Wherever yours is, take some time to understand how it works and you be halfway to understanding manual exposure.
- Auto Modes And Exposure Compensation
- Why You Should Use Exposure Compensation On Your Next Journey
- Exposure Compensation: Use it to Master Exposure and to Explore Your Creativity
- DSLR Camera Basics
- What Is Exposure Compensation – And When Should I Use It On My Camera?
- Exposure Compensation: How to Use it Correctly