Photography Beginner

Exposure Mode (Metering) When you press the shutter whilst using the camera on automatic exposure, the camera has to determine what exposure it will take a photograph at, so it can capture the most evenly and well lit picture overall.

Many compact cameras now include several exposure settings which change how the camera works out the exposure for each picture, so even though you are asking the camera to make the exposure calculation for you, you can still have some input into which part of the subject you want the camera to take into consideration when it is working out the exposure for the picture.

Evaluative metering - In the main, most compacts will have a general mode of metering, normally called evaluative or average, because the metering sensor looks at every part of the subject contained in the camera frame (the area of the subject you are looking at through your camera and can see on the view screen or through the view finder), considers the light coming from all areas and then it works out what exposure will give the best shot.  This is a good reliable mode of metering for normal day to day photography, where everything is fairly evenly lit, no big bright spots.

Center Weighted metering - Another mode of metering, called center weighted, works almost identically to Evaluative metering, with one small addition.  It too considers the entire frame when deciding on the exposure, but it also looks a little more closely at the subject at the center area of the frame and gives an overall exposure that suits the center most of all.  It gives more weight, or preference, to the subject at the center, so if you are taking a picture of something that is in the center of the shot, it will have a better overall exposure for that subject.

These metering systems work well under normal conditions but start to struggle to give correctly exposed photographs when there are large areas of brightness or darkness in the picture, or when the light source (the sun or indoor lighting) is directly in front of the camera.

Because the sensor evaluates the whole scene that the camera is looking at, if there are large dark or bright areas, the sensor can be fooled into thinking that there is more or less light than there really is, so it over compensates for the large area.  The resulting photo is either too dark because the camera thought the large white area was a lot of light, or the photo is too bright because it compensated too much for what it thought was an area of deep shadow.

When the light is in front of the camera, such as when you are trying to take a picture with the sun directly in front of you, the sensor cannot make enough allowance for the bit of the subject you are really trying to capture.  When this happens, too much light from the sun (or any other light source) goes into the camera.  What does that mean to you trying to take a photograph?

At one time or another, most people have tried to take a picture of a person standing in front of a window.  What happened?  You got a nicely exposed picture of the street but the person’s face was in such deep shadow you couldn’t really make out who it was.  This is a prime example of the way the metering sensor can be tricked into giving the incorrect exposure.

We see objects because light hits them and then comes to our eye.  When something we want to photograph is standing with a strong light source behind it, that light source is going to go straight into the camera, but the subject may only have whatever light is being reflected off the walls to light it.

Since the light source is more powerful than the light being reflected off the actual subject, it will overpower the sensor and make it think that what you want to take a picture of is brighter than is actually is.

What you will get is a nicely exposed picture of the light source but little else.  There are a number of ways you can rectify this kind of situation.  We’ll look at two ways here.  You could change to a different metering mode, spot metering, or you could use a little trick most compacts have up their sleeve – Exposure compensation.

Spot metering – Unlike evaluative and center-weighted metering, spot metering takes the exposure reading only from a very small point at the center of the frame.  Because of this, it is not affected or influenced by any other part of the scene and so will produce the correct exposure for your subject if you keep that subject at the center of your picture frame, even if you stood a person against a black wall or a white wall.

With spot metering, as long as the person was standing in the center of the picture, the camera would only take an exposure reading from the person and ignore whatever else was around them, and the exposure would be precisely correct for them.

Exposure Compensation (EV+/-)

Many compacts now have a quick facility to override and make an adjustment to the camera’s exposure reading when the lighting conditions will fool the camera into either under or over exposing the photograph (as described in the section on metering solutions).  Exposure compensation allows you to quickly tell the camera to allow more or less light in for the exposure.  On your camera, you will find an EV scale that has a zero center and extends 2 or 3 stops in both + and – direction, in 1/3rd increments.

If you go up the + side, you are letting more light in, so increasing the exposure.  If you go down the – side, you are giving the picture a shorter exposure, letting less light in.

Try moving up and down this scale whilst watching the back view screen of your compact camera.  You will see the way this changes the overall lighting on the screen and ultimately within your photograph, making it lighter or darker, depending on which way you move along the scale.

With practice, you will be able to use the exposure compensation to enhance the look of your pictures by being able to compensate quickly when lighting conditions call for your main subject to be given more or less exposure.

So the next time you want to take a picture of someone standing in front of a window, you can dial in 1 or 2 stops on the + scale and amaze your friends by getting them perfectly exposed when their own photo will be too dark!

The “Built-in Flash” is up next.

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