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For each DSLR, there is an exposure
compensation setting. Exposure compensation is used in a time when we
have completed metering for a photo, yet due to the environment
situation or some reason, we would like to change the exposure
accordingly, either increasing or decreasing the exposure.
In most environments, the lightning would be sufficient for the DSLR to
make an accurate metering and determine the correct exposure. However,
in situation whereby there are some drastic changes in brightness, the
camera might have problem to meter correctly. Thus result a wrong
exposure, either over expose or under expose of the photo.
A typical example is when we are trying to take photo in a place that
is light in color whereby a lot of light is reflected or in a place
where there is present of external lighting, both resulting the
metering system of camera to misjudge. The camera would have metered
that the environment is actually brighter than it is supposed to be and
this resulted with an EV value that is lower than it should be. As a
result, the outcome of the photo will be a lot darker.
Another example is when we are taking photo in a place that have a lot
of objects that is dark in color or very low reflective objects; as
most of the lighting is absorbed, the camera would metered and
misjudged that the surrounding is actually darker than actual case. As
a result, the camera will come up with an exposure value that is lower
and produce photos that is overexpose. The photo will be too bright.
In order to make changes on exposure value without changing on the
aperture setting and shutter speed, the easiest way is to change in
exposure compensation setting. The setting of exposure compensation is
simple and direct: either increase or decrease directly in the exposure
value.
The exposure compensation is measured in EV (exposure value as
discussed in aperture, shutter speed, metering, ISO), meaning one level
= one stop. Usually the camera will allow us to change it with a
stepping of 1/3 stop or ½ stop. And most of the DSLR will have an
exposure compensation range of plus minus 2 stop.
Photo with normal exposure
Picture with EV setting +1
Picture with EV setting -1
How do we know how much exposure value to change when the camera make a
mistake in metering? There isn’t any exact rule. For different
situation, there will be different e exposure value that we need to add
in or decrease. And in most situations, it will depend on our own
judgment and experience to decide on the correct exposure value.
One thing good about digital camera is, we can always try and error.
Take several photos with different exposure value and slowly we will
gain more knowledge on how to control exposure compensation.
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