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One of the most important thing in photography is exposure and lighting .
Why it is so important exposure time and the light ? , one of the most important is because a picture that’s too dark or too light can’t be corrected or it’s very hard to correct even with an editing software .
In this article we will try to explain how exposure related things like ISO , shutter speed and aperture affects the quality of your pictures .
We explained how digital photo is created when light passes through the camera lens and strikes the image sensor but the brightness and contrast of the resulting image depends on three main factors:
The f-stop which is the aperture setting and controls the amount of light that strikes the image sensor.
The shutter speed which determines the length of time the light is allowed to hit the sensor.
The ISO setting which controls how sensitive the image sensor is to light.
How much control you have over these settings depends on your photo camera , on digital SLRs and high-end point-and-shoot models you get full manual exposure control .
After the light enters in the camera lens it must past two barriers : aperture and the shutter.
The aperture is positioned behind the lens and is a hole in an adjustable diaphragm.
The shutter is normally closed and when you press the shutter button, the shutter opens briefly to let the light in and the image sensor records the image.
By controlling the aperture size and the time of the shutter you can vary the amount of light that strikes the image sensor.
The size of the aperture is measured in f-numbers more commonly referred to as f-stops. Standard aperture settings are f/2.8, f/4, f/5.6, f/8, f/11, f/16, and f/22 .
If the f-stop number high the aperture size is small and less light enters the camera. Each f-stop setting lets in half as much light as the next lower f-stop number.
To test the F-Stop , to see how it works just take two pictures with your photo camera one with high f-stop ( the aperture is open a little bit ) and other photo with low f-stop (big aperture opening) and you will see that the background is more blur when the f-stop is low . when you try this make sure that you have a clear focus when you using low f-stop so at least one object will be in focus .
In some camera technical specifications you will find the f-stop settings without f/ , just 2.8, 4, 5.6, 8, 11, 16 , etc.
F-stops are also designed so each step of smaller aperture will cut the amount of light in half.
If you move the aperture setting o in one direction, to cut the amount of light in half, you can exactly compensate for that loss of light by moving the shutter speed setting in the other direction to double the amount of light ( adjust shutter speeds in one direction, to let more or less light in, and F-stops in the other ).
If you can remember this simple rule, you can use manual mode of photo camera .
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