How accurate is your Camera Exposure control? Even though digital camera has several abilities to control the exposure, there are many practical ways to trick the camera exposure after production such as correcting the exposure in the computer by using image editing tools; software like Adobe Photoshop.

How to adjust the camera exposure?

Mostly digital cameras have similar exposure reading chart. A common display of the camera exposure reading chart is shown below.

The triangle in the middle chart is the position of ‘No Compensation’ camera exposure. The small line at the bottom side is the pointer which you can adjust to the right (camera exposure increased) up to +2EV; or to the left (camera exposure decreased) up to -2EV. Commonly this setting can only be used in ‘manual’ mode setting in digital cameras. Please refer to your digital camera manual book how to adjust the settings. This is the manual setting that you will work with all the time when you compensate the camera exposure.

Camera exposure chart

To describe the brightness level of the object due to the changes of camera exposure control, the photo below will demonstrate different level of camera exposures. All the photos use the same aperture but with different level of shutter speed. Look; how the camera response with the object that has two different level of contrast – brightness and darkness.

Exposure level

You probably prefer an overexposure photograph that demonstrates the subject surface with a high key effect. Or probably prefer silhouette – the darker one; or even you probably prefer to use image editing tools in the computer after production to trick the camera exposure and play with the tone.

We all know that the camera system can accommodate difficult level of lighting. But the system is not sensitive at all to the intrinsic brightness or darkness level of specific objects. Of course they will influence to the result of your photograph. Unsuccessful camera exposure results of your photograph mostly because dealing with this kind of intrinsic brightness or darkness level of the objects. It is not neither due to difficult lighting nor your fault.

Dark or Black Tone

The following experiment will show you how to trick the camera exposure in dealing with the intrinsic brightness or darkness level of specific objects.

We use a black background to capture combination of black subject with white ceramic spoon on the foreground and applying ‘No compensation’ camera exposure setting. Guess what? The camera will not be able to capture it correctly. Please observe the photo result thoroughly; and you will find that it is an overexposure (OE) result. What the camera can do is measuring the lighting level received by the image sensor. And it is not surprising if the camera increases the level of exposure. The camera exposure is not smart enough to deal with this kind of intrinsic darkness. You can guess the result, that the object and the background will be increased to 18% grey or equal to 2EV.

dark background, dark object, no compensation

The lens and the ceramic spoon photo is actually interesting enough if presented with the proportional light. Now take a look at the above overexposure photo particularly the ceramic spoon on the foreground. On the real condition the spoon is almost white tone. But since the camera exposure was increased up to +2EV the spoon becomes very bright and tends to be excessive white.

Now have a look at the photograph below with different level of the camera exposure. By controlling the camera setting and reducing the camera exposure up to 2 EV, you can either restore the black objects (the lens and the background) into the proper black tone but you can also restore the spoon tone into the correct white tone.

Dark background, dark object, -2EV compensation

You can apply this tricking the camera exposure technique to the black bird with bright beak, for example. If you capture the dark tone objects, the camera often increases the exposure; so reducing the light detail on some areas of the object. You can also try to capture an object which the dark tone is not as extreme as the above examples. For example capturing a series of trees with dark tone, reduce the exposure from 0.7 EV up to 1 EV to keep the color depth and lighting detail.

Bright Tone

Object with the dark tone that causes complication is not the daily problem you meet. Even a more common tonal problem is the bright tone that frequently causes distortion to the camera measurement. The result of the experiment using the bright objects can be predicted evidently. All the elements here use the bright objects. You probably expect that the camera will control the exposure correctly without any adjustment. But the result is not as good as when you increase the camera exposure up to +1/3EV

Midtone - no compensation

By increasing the camera exposure to 1/3EV you can recover the brightness of the object clearer and more realistic. At the beginning you must do the experiment several times to get a correct compensation EV value for the dark or bright objects. By keep practicing and understanding the character of your camera, it will be easier to adjust it when you capture various tonal objects.

Bright tone with +1.3 EV

White Tone

White tone objects are common cases, and become the main source of problems in underexposure cases where the camera cannot read the exposure correctly. As we know that the nature is full with the white objects and backgrounds and you will realize that how bright they are. An experiment was made to capture the bright objects below. We would like to capture the object by expecting the result as real as the original object; not as an 18% grey as assumed by the camera metering system.

White tone, no compensation

By using the default ‘no compensation’ in the camera exposure you probably expect a good photo result, but that is completely wrong. The result is under exposure photo. In this case; the camera reduces all the tone with the same value.

To restore the object into its original white tone, you need to compensate the camera exposure value up to 2 EV. You can apply the same technique when you capture the snow or any other white objects.

White tone - plus 2EV compensation

It is clear now how to manually compensate the default camera exposure when dealing with dark or white tones.

Keep practicing and good luck.

Related articles:

• Basic exposure – an understanding the basic exposure in photography
• Photography background issues – tricking the camera exposure
• Lighting techniques – a general discussion in photography lighting
• Photography Technical Skills