Aperture Photography In optics an aperture is a

�In optics, an aperture is a hole or an opening through which light travels

�The aperture stop of a photographic lens can be adjusted to control the amount

�The aperture functions much like the iris of the eye – it controls the

Modern lenses use a standard f-stop scale ◦ f/1. 4 ◦ f/2. 8 ◦

�Each full stop up on the F-Stop scale represents an open that lets in

Depth of Field �Depth of Field refers to how much of the image is

�High f/stop numbers (smaller openings) produce more depth of field ◦ Images have more

�Lower f/stop numbers (larger openings) produce less depth of field ◦ Images have less

�Higher F-Stops (smaller openings) require more light (longer shutter speeds and/or more sensitive film)

�The blurring in the background of pictures is referred to as Bokeh. �The shape

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Aperture Photography

�In optics, an aperture is a hole or an opening through which light travels �More specifically, the aperture of an optical system is the opening that determines the cone angle of a bundle of rays that come to a focus in the image plane. �The aperture also determines how many of the incoming rays are actually admitted and thus how much light reaches the image plane (the narrower the aperture, the darker the image for a given exposure time).

�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 functions much like the iris of the eye – it controls the effective diameter of the lens opening. �The lens aperture is usually specified as an f-number, the ratio of focal length to effective aperture diameter. �A lower f-number denotes a greater aperture opening which allows more light to reach the film or image sensor.

Aperture

Modern lenses use a standard f-stop scale ◦ f/1. 4 ◦ f/2. 8 ◦ f/4 ◦ f/5. 6 ◦ f/8 ◦ f/11 ◦ f/16 ◦ f/22 ◦ f/32 ◦ f/45 ◦ f/64 ◦ f/90 ◦ f/128 ◦ etc

�Each full stop up on the F-Stop scale represents an open that lets in half as much light as the stop before it ½ as much light as f/1 ½ as much as f/1. 4 ½ as much as f/2. 8 ½ as much as f/4 Etc.

Depth of Field �Depth of Field refers to how much of the image is in focus. �Three factors play a hand in determining or affecting depth of field: the lens aperture (how open the lens is), the length of lens being used and the object’s size (the later includes the distance the object is away from the photographer).

�High f/stop numbers (smaller openings) produce more depth of field ◦ Images have more in focus F/22

�Lower f/stop numbers (larger openings) produce less depth of field ◦ Images have less in focus f/2. 0

�Higher F-Stops (smaller openings) require more light (longer shutter speeds and/or more sensitive film) to gain proper exposure.

f/4. 0 - 1/6 sec – ISO 100

f/22 - 5 sec – ISO 100

f/4. 0 – 1/4 sec – ISO 100

f/22 - 8 sec – ISO 100

�The blurring in the background of pictures is referred to as Bokeh. �The shape of the bokeh is determined by the number of blades used to open and close the aperture.