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.
Exposure, in digital or film photography, is determined by aperture and shutter speed. On a manual camera, the user selects both values.On an automatic camera, there are four possibilities:Manual mode. User selects both aperture and shutter speed.Shutter priority. User picks the shutter speed and the camera adjusts the aperture to ensure proper exposure.Aperture priority. User picks the aperture and the camera adjusts the shutter speed to ensure proper exposure.Program mode. The camera selects both values.
Manual cameras require the user to set the focus, shutter speed and aperture. An automatic-exposure camera sets either the shutter speed (this is an aperture priority camera), the aperture (this is a shutter priority camera) or both (this is a programmed-exposure camera). An autofocus camera sets the focus, and all those cameras have automatic exposure.
If you're using a DSLR (digital single lens reflex) camera, you need to have it set to Av (aperture priority). The lower your aperture, the less depth of field and vice versa. If you're using a point and shoot camera, you cannot manually control your aperture settings, the various modes do that for you.
Give me food and I will live give me water and I will die what am I?
What is 8 divided by 2(2 plus 2)?
A farmer has 19 sheep All but 7 die How many are left?
What is pokediger1s password on roblox?
Who was Hillary Clintons running mate in the 2008 presidential elections?
How many triangles in a pentagram?
How do you get 1000000 robux for free?
What is the toughest academic course according to the Guinness Book of World Records 2011?
Why do so many foods "taste like chicken"?
Who invented Lincoln Logs?
How did chickenpox get its name?
What is doomscrolling?
How did the Wiffle Ball get its name?
Do schools still teach cursive writing?
Can eggs break inside a chicken?
How is kottatchiyar in English?
What are good qualities of a resource mobilizer?
How is medium a factor in representing the filipino identity in a work of art?
How do you transulate happy independence day in konkani language?
How should the state react the violation of law?
Advantage and disadvantage of on premise catering?
Which scene from the Beowulf reading is a flashback?
What day is national godchild day?