ISO, Shutter Speed and Aperture

The effects of ISO, shutter speed and aperture. 

ISO is how sensitivity the camera is to light. The lower ISO setting that you have aloud you to have a high aperture setting or longer exposure. Image quality is better when you use a low ISO this is because less noise grain is being let into the camera. If to much noise has been aloud into the photo there will be a pattern of pixels or a group of pixels, and the colours are different to what they should be.

Aperture is the lens opening and controls the amount of light that is passing throughout the lens. This is measure by f/stop. The lower the aperture is where the pupil of the lens is at its widest, letting in the most light. The higher the aperture is where the pupil of the lens is a small hole which is letting in a small amount of light. The lower your aperture the shallower your depth of field will be, and you will have blur in the background or foreground. The higher the aperture the wider the depth of field will be and the sharper the frame will be. Choosing the right aperture is important for the depth of field that you want, this is because the it allowing you to control what is in focus and what is out of focus.
Here is an example of low aperture and having a shallow depth of field. The bird in the foreground is in focus and the background is blur and out of focus.                                                                                                                  

Here is an example of high aperture and having a high depth of field. Anything within this photo is in focus, this is because they lens is allowing less light into the camera.





Shutter Speed is how long the shutter is open for, the long the shutter speed is shut the more motivation blur there will be in the image.  A faster shutter speed can freeze movement and a slower shutter creates motivation blur from a moving object. If you use a slow shutter speed you can pan a moving image. Shutter speed also effects the amount of light that is coming into the photo, because of the time the shutter is open for.

ISO, aperture and shutter speed work together to get the correct depth of field and light into the frame.


Book: Digital video handbook, Tom Ang, 2005, Penguin.
Photos: Google Images.