What is an aperture of a camera?

Answer 1

Original answer moved to discussion page.

The aperture is an opening within the lens whose size is controlled by a series of overlapping blades. It's sole purpose is to control the amount of light that reaches the film or digital sensor during the exposure time. Anything else, such as depth of field, is a spin off of its function.

The size of this opening is controlled by settings on the camera shutter speed/aperture dial or on the lens. Many cameras do not have the ability to "stop down" the aperture before the moment of exposure, so it is not something most people can observe. At the moment of exposure, the blades move to create an opening within the lens just before the shutter opens to control the duration that this occurs. Together, they control the exposure.

We quantify the size of this opening with F numbers. Simply put, the F number expresses how many times an aperture will fit into the focal length. Thus, in a 100mm lens, F4 means it will fit in 4x and will be 25mm in diameter. In a 200mm lens, F4 represents an opening of 50mm. This explains why longer length lenses typically have larger maximum apertures, and why the higher F number represents a smaller aperture (F16 must fit into the focal length 16x, thus it has to be smaller).

The answer moved to the discussion page, while good, was more about the effect of the aperture and really belongs in a answer to a question about depth of field.

Answer 2

Aperture on a camera is the size of the opening/hole in the lens that allows light through. A larger opening lets more light through per second than a smaller one. The size of the opening also affects the depth of field (DOF) in the photograph in the following way: Large opening ------- Small opening Shallow DOF ------- Deep DOF See these links for more detailed info. Aperture http://en.wikipedia.org/wiki/Aperture Depth of field http://en.wikipedia.org/wiki/Depth_of_field

Answer 3

The word aperture refers to the diaphragm opening inside a photographic lens. it works in a similar way to the iris in the human eye. Just like the iris regulates the amount of light that passes into the eye by closing and opening, the size of the diaphragm opening in a camera lens regulates the amount of light that passes through the lens onto the film inside the camera at the moment when the shutter curtain in camera opens during an exposure process.

The size of an aperture in a lens can either be fixed (like most compact cameras) or adjustable (like an SLR camera). Aperture size is usually calibrated in f-numbers or f-stops, i.e. those little numbers engraved on the lens barrel, e.g. f/22, f/16, f/11, f/8.0, f/5.6, f/4.0, f/2.8, f/2.0, f/1.8 etc. Each of these values represents a factor of the amount of light that passes through the lens. The smaller the number, the larger the aperture, e.g. a standard f/1.8 50mm lens has a largest aperture of 1.8. Each following f-stop lets in half as much light as the previous, so f/2 will let in half as much as f/1.8, f/2.8 will let in a quarter as much, etc. The result of this is that the exposure time is doubled each time a smaller aperture is selected.

The aperture size will also affect the field of depth, so that a portrait photographer will normally choose large apertures (small f-stops) which produce very small depths of field (subject in focus, background out of focus) and a landscape photographer will choose small apertures (large f-stops) which produce large depths of field (everything in focus from near to far)

Answer 4

The aperture is like the eye-lid on a human. It decides how much light to let through to the sensor.

Answer 5

The picture was overexposed because I had the aperture too large for the shutter speed.

Answer 6

The hole that lets in light in the shutter that creates your image.

Answer 7

An aperture is an opening, a hole, or a gap. In Photography, the aperture refers to the size of the hole through which light is allowed into the camera to take a photograph.

Answer 8

To allow in light.