In case you are new to photography, you may feel it is convenient to just put your digital camera on automatic and hope for the best. If you do, I bet you will soon get a bit frustrated with how your pictures often don’t come out the way you intended, and you sit there wondering what’s going on.
Take the clown picture here for example. Imagine how dull it would have been if you had taken the picture using automatic settings. The camera would then have fired the built-in flash unit and ruined the mood of the event (and you may also have gotten thrown out for disturbing the act!).
On the contrary, the photographer here had total creative control. He took the picture using the ambient light, and used a very long exposure time. And, yes, the result was motion blur.
However, what do you feel when you see that “blurry” photograph? Personally, I feel it is a great shot! And you could never make a picture like this unless you had creative control over your camera.
To begin with, there are basically THREE WAYS you can control how the image is exposed in the camera when you press the shutter. You can think of these as the three tips of a triangle; the Exposure Triangle.
1. Exposure Time = Shutter SpeedThe exposure time, also known as “shutter speed”, determines how long time the camera sensor is exposed to the light from the subject of interest. Long exposure is another word for slow shutter speed.
2. Aperture = Size of Light Opening
3. ISO Setting = Sensor-sensitivity
The aperture setting determines how big the opening is allowed to be, for the light coming in. And remember that the larger the aperture opening, the lower the number on the aperture scale. Expensive camera lenses usually allow the use of larger apertures, making it easier to work with them in low light.
Finally, the ISO setting determines how high you crank up the light sensitivity of the sensor unit in the camera - the part that transfers incoming light to an electronically stored image. Higher sensitivity means more “noise” in the image. To get the best quality you usually set this to 50 or 100 ISO units.
So, a few words on shutter speed. Generally, if nothing you’re trying to capture is moving much you can use shutter speeds down to maybe 1/60 of a second. With practise, you can use even slower shutter speeds, ie. longer exposures, for non-moving subjects. In case you want to freeze movement, you need a faster shutter speed. For instance, a car driving past you and going fast may require a shutter speed of 1/500 of a second to “freeze” its movement. The picture of the surfer here was shot at a very fast shutter speed, to “freeze” the movement. Fast movement = fast shutter speed.
To get creative control over the shutter speed point of the Exposure Triangle, you need to consider how you want to use that setting to control the mood of the image. Like, do you PREFER to “freeze” the movement by using a fast shutter speed, or would you rather experiment with a very slow shutter speed to get intentional motion blur, as in the clown picture?
In the case of the clown picture, the low ambient light wouldn’t allow a very fast shutter speed - and neither would it be needed or even desirable in that situation. Conversely, in the surfer photo the light was quite strong which allowed the photographer to snap the picture at a fast shutter speed - likely 1/500 of a second or even faster.
You could have made a very different surfer picture by using a slower shutter speed, to create some motion blur. Then you would have needed to adjust the two other points of the Exposure Triangle accordingly - smaller aperture and/or lower ISO setting, to avoid over-exposing the image
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