Shutter Speed Aperture and ISO
Shutter Speed
We now know that the shutter speed of a camera influence the amount of light able to reach the sensor of the camera, affecting how bright or dark the resulting image will be. The shutter speed of a camera is usually measured in seconds, as shown earlier. Most cameras typically are able to operate up to shutter speeds of 1/4000 of a second. The effects of varying the shutter speed of a camera can be seen in the photo below.
Starting from 1/20 of a second, the resulting image is overexposed, with the background being blown out. As the shutter speed is increased to 1/50 of a second, the image gets more well exposed, with the background being more visible. At 1/100 second, a balanced exposure is achieved. Increasing the shutter speed progressively causes the image to get underexposed as in the case of 1/400 second.
Aperture Size
The aperture size of the lens also affects the amount of light incident on the image sensor. The aperture size of a lens is measured in terms of the focal length divided by the diameter of the lens, known as f-stop values.
The common f-stop values are typically f/1.4 , f/2 , f/2.8, f/4, f/5.6, f/8, and so on. Hence, a LARGE aperture size will correspond to a SMALL f-stop value (f/1.4), and a SMALL aperture size will correspond to a LARGE f-stop value (f/22).
Its just maths, go think about it, assuming a constant focal length of 50mm, dividing by a small value (f/1.4) gives u a large result (aperture size). The opposite applies.
The image below shows the different aperture sizes with f-stop values.
The aperture size affects the image brightness in the same manner as the shutter speed. Using a large aperture allows more light to pass through and thus result in a brighter image. In addition to that, the aperture size influences the depth of field (DOF) of the resulting image.
Depth of Field (DOF)
The depth of field refers to the area of a photo that is in focus which is affected by the aperture size. A large aperture size would result in an image with a low DOF, while a small aperture size would result in an image with a high DOF. The image below shows how the DOF changes with decreasing aperture size.
At f/1.4 (wide open), only the front portion of the truck is in focus and everywhere else is out of focus (OOF). This is referred to as a shallow DOF. Decreasing the aperture size gradually increases the DOF of the photo, till at f/16 the entire photo including the background is in focus.
ISO
Lastly, the ISO setting of the camera affects the exposure of the image as well. ISO is defined as the sensitivity of the image sensor to light. The higher the ISO, the brighter the image will be, assuming shutter speed and aperture size are kept constant. However, increasing the ISO setting results in a trade-off of image quality for sensitivity. The resulting image will have a grainy feel as seen in the example below.
Increasing the ISO from 200 all the up till ISO 3200 results in an increasingly grainy image as shown in the enlarged portion on the right.
We now know that the shutter speed of a camera influence the amount of light able to reach the sensor of the camera, affecting how bright or dark the resulting image will be. The shutter speed of a camera is usually measured in seconds, as shown earlier. Most cameras typically are able to operate up to shutter speeds of 1/4000 of a second. The effects of varying the shutter speed of a camera can be seen in the photo below.
Starting from 1/20 of a second, the resulting image is overexposed, with the background being blown out. As the shutter speed is increased to 1/50 of a second, the image gets more well exposed, with the background being more visible. At 1/100 second, a balanced exposure is achieved. Increasing the shutter speed progressively causes the image to get underexposed as in the case of 1/400 second.
Aperture Size
The aperture size of the lens also affects the amount of light incident on the image sensor. The aperture size of a lens is measured in terms of the focal length divided by the diameter of the lens, known as f-stop values.
The common f-stop values are typically f/1.4 , f/2 , f/2.8, f/4, f/5.6, f/8, and so on. Hence, a LARGE aperture size will correspond to a SMALL f-stop value (f/1.4), and a SMALL aperture size will correspond to a LARGE f-stop value (f/22).
Its just maths, go think about it, assuming a constant focal length of 50mm, dividing by a small value (f/1.4) gives u a large result (aperture size). The opposite applies.
The image below shows the different aperture sizes with f-stop values.
The aperture size affects the image brightness in the same manner as the shutter speed. Using a large aperture allows more light to pass through and thus result in a brighter image. In addition to that, the aperture size influences the depth of field (DOF) of the resulting image.
Depth of Field (DOF)
The depth of field refers to the area of a photo that is in focus which is affected by the aperture size. A large aperture size would result in an image with a low DOF, while a small aperture size would result in an image with a high DOF. The image below shows how the DOF changes with decreasing aperture size.
At f/1.4 (wide open), only the front portion of the truck is in focus and everywhere else is out of focus (OOF). This is referred to as a shallow DOF. Decreasing the aperture size gradually increases the DOF of the photo, till at f/16 the entire photo including the background is in focus.
ISO
Lastly, the ISO setting of the camera affects the exposure of the image as well. ISO is defined as the sensitivity of the image sensor to light. The higher the ISO, the brighter the image will be, assuming shutter speed and aperture size are kept constant. However, increasing the ISO setting results in a trade-off of image quality for sensitivity. The resulting image will have a grainy feel as seen in the example below.
Increasing the ISO from 200 all the up till ISO 3200 results in an increasingly grainy image as shown in the enlarged portion on the right.
Labels: basic, photography, shutter speed
posted by white5tar at 12:39 AM
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