The aperture stop of a photographic lens can be adjusted to control the amount of light reaching the film or image sensor. In combination with variation of shutter speed, the aperture size will regulate the film's or image sensor's degree of exposure to light. Typically, a fast shutter will require a larger aperture to ensure sufficient light exposure, and a slow shutter will require a smaller aperture to avoid excessive exposure. The aperture largely controls the brightness of an image through the amount of light the lens allows in but also changes the focus of the camera through adding blur. With a large aperture, the focus of an image will be further highlighted as a large amount of the image (mainly the background) will be blurred. This is the opposite with a small aperture as very little or no part of the background will be blurred making for a very sharp and clear image.
Aperture is measured in 'f-stops or 'f-numbers'. They refer to the ratio of the system's focal length to the diameter of the entrance pupil. The f-number is found by dividing the focal length by the diameter of the entrance pupil. For example, if a lens's focal length is 10 mm and its entrance pupil diameter is 5 mm, the f-number is 2.
I would use a large aperture when photographing someone for a portrait as it would draw attention to the model and help to reduce anything in the background becoming too much of a distraction. I would use a small aperture when photographing a landscape as I would want everything in the frame to be captured and to be a sharp, clear image.
Below is a visual example of how aperture can be used to create entirely different images suited to particular situations such as times of day or particular lightings.
Aperture is measured in 'f-stops or 'f-numbers'. They refer to the ratio of the system's focal length to the diameter of the entrance pupil. The f-number is found by dividing the focal length by the diameter of the entrance pupil. For example, if a lens's focal length is 10 mm and its entrance pupil diameter is 5 mm, the f-number is 2.
I would use a large aperture when photographing someone for a portrait as it would draw attention to the model and help to reduce anything in the background becoming too much of a distraction. I would use a small aperture when photographing a landscape as I would want everything in the frame to be captured and to be a sharp, clear image.
Below is a visual example of how aperture can be used to create entirely different images suited to particular situations such as times of day or particular lightings.
As seen below, I have taken my own photos to demonstrate the use of aperture. I took 3 sets of images with various f-numbers: one with f-5.6, one with f-11 and one with f-22. Clearly seen in the pencil pictures, the lower the f-number is, the more focused the focus of the photo is and the more blurred the background is. As the f-number increases, the background becomes less blurry and is sharper.