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F-number

F-number
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F-Number
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F-Number
F-Number, also known as a focal ratio, is the ratio of the diameter of the lens aperture to the length of the lens. On a camera, a photographer can alter the f-number by changing the f-stop setting on the camera's lens.

The larger the f-number, the smaller the lens opening. In the aforementioned series of numbers, f/1.4 is the largest opening and f/22 the smallest. The smaller the number, the greater the depth of field in a photograph, and vice versa.

f-NUMBER - (ƒ-number) A number that expresses a lens' light-transmitting ability - i.e. the size of the lens opening.

F-numbers or F-stops
Numbers on the lens aperture ring and the camera's LCD (where applicable) that indicate the size of lens aperture. The lower the number the larger the aperture. As the scale rises, each number is multiplied by a factor of 1.4.

f-number - Also known as f-stop, the f-number refers to the ratio of the aperture of a camera's lens to its focal length.

F-number : The numbers on the lens aperture ring and the camera's LCD that indicate the relative size of the lens aperture opening.

F-numbers. See Aperture.
Feather. To fade the borders of an image element so that it blends more smoothly with another layer.

F-stop (f-number). A numerical designation (f/2, f/2.8, etc.) indicating the size of the aperture lens opening.
Grain. The particles of silver that make up a photographic image.

F-number: lower is better.
IS is "image stabilization", a technology lifted from camcorders in which the camera electronically compensates for unsteady hands. IS is especially important at long focal lengths, e.g.

f-Number - A number that indicates the size of the lens opening on an adjustable camera, where smaller the number (f/1.4, f/2, f/2.8, f/4, etc) the larger the lens opening.
...

F
F-Number, F-Stop
See Aperture.
Fill-In Light
Additional light from a lamp, flash, or reflector; used to soften or fill in the shadows or dark picture areas caused by the brighter main light. Called fill-in flash when electronic flash is used.

The f-number is the expression of the size of the aperture opening for a lens's given focal length. In its most basic terms, the f-number is the lens's focal length divided by the "effective" aperture diameter.
F/stop ...

The "f-number" defines the relation between the focal length of a lens (e.g. 50mm) and the diameter of the opening of a lens (roughly the size of the entrance pupil = front element) ...
f-number = (effective focal length) / (clear aperture) ...

Because f-numbers are fractions of the focal length, "higher" f-numbers represent smaller apertures.
Maximum Aperture or Lens Speed ...

F-Stop or F-Number - number used to measure the size of the camera's aperture
Fill Flash - flash used on a bright day to fill in harsh shadows ...

The lower the f-number the shallower the depth of field. On Av setting the camera will automatically work out the correct shutter speed required.
Long exposure ...

Aperture and f-numbers.
The aperture is just a hole whose size can be varied to allow more or less light to pass through it. The size of apertures are expressed in f-numbers.

For camera optics, F-number is usually used instead of NA, where NA=1/2F.

The hole or opening formed by the metal leaf diaphragm inside the lens; controls amount of light and depth of field, prevents vignetting and reduces lens aberrations; the size of the aperture is indicated by its f-number, i.e.

A small f-number ( large aperture diameter) gives a small depth of field, and a large f-number gives a large depth of field. Full Well Capacity Each photosite on a CCD chip can contain a certain number of electrons.

The wider the aperture (the smaller the f-number), the more light goes in. This allows you to use faster shutter speeds (less motion blur) and lower ISOs (less grain), so a wide aperture (a "fast lens" with a low f-number) is always desireable.

F-number (See also: Aperture) The set of numbers on the lens aperture ring indicating the relative size of the lens aperture opening.

The next supposedly confusing thing about aperture is that the f-number sequence goes in stop increments: 1, 1.4, 2, 2.8, 4, 5.6, 8, 11, 16, 22, 32. There is a logic to this.

The common f-numbers on 35mm cameras are f1.4, f2, f2.8, f4, f5.6, f8, f11, f16, and f22. The larger the f-number, the smaller the lens opening, f22 is the smallest in this series.

The size of the aperture is measured using an f-number also called the f-stop (F8, f/8, etc). The smaller the f-number, the larger the camera's opening. The size of the aperture directly affects depth of field and shutter speed.

The smaller the size of the lens aperture (the larger the f-number), the greater the depth of field. The larger the aperture, the shallower the depth of field.
Camera-to-subject distance.

If the aperture is wide open (indicated by a small f-number), lots of light will get inside and you will be able to take good quality photos even in dark conditions.

Maximum Aperture The maximum diameter of the lens opening is referred to as its maximum aperture or minimum f-number. The minimum f-number is the smallest f-number that can be selected with the lens. Find out more.

Small aperture (large f-number) means large depth of field, but since the opening is smaller less light comes in (peephole vs. panoramic window).
-Exposure time is how long we let the light in.

On digital SLR cameras, aperture is indicated by a f-number value.
The higher the F number, the more of the photo that will be in focus.

Generally, a larger aperture (smaller f-number, e.g. f/2) has a shallower depth of field, anything behind or in front of the main focus point will appear blurred.

Ideally you would by a lens with as large aperture (small f-number) as possible. These digital camera lenses allow you to shoot in low light conditions and when you need a fast shutter speed like in sport and action.

-Lens speed - largest lens opening (smallest f-number) at which a lens can be set. A fast lens transmits more light and has a larger opening than a slow lens. Determined by the maximum aperture of the lens in relation to its focal length.

So, let's say we have a lens with a focal length of 50mm and the f-number is f/1.8. The f-number is determined by focal length/aperture. So 50/x=1.8 or x~=28. The actual diameter where the light comes through the lens is 28mm across.

If you divide the focal lenght of the lens into its aperture f-number you get the diameter size of the effective aperure in the lens.

F-stop also known as f-number, this is the measure used to determine the relative aperture size of a lens. It is calculated by dividing the diameter of the aperture opening by the focal length of the lens.

An f-stop (sometimes referred to as f-number) is a measure of aperture size. It is expressed as the focal length divided by a number. For example, f/8 means focal length divided by 8 so, an 80mm lens at f/8 would have a 10mm opening.

When opened wide (smaller f-number) the zone of sharp focus can be very narrow. Portions of the image become progressively more blurry as they get farther away from the focal plane (plane of perfect focus). This works in both directions.
4. A-Dep ...

Aperture controls the amount of depth of field or how much is in focus, the smaller the f-number eg. 2.8 the item in focus will be crisp, clear and sharp but your backgrounds and foregrounds will be out of focus ...

You probably know that to get maximum depth of field with any lens, you should shoot using the smallest aperture the lens permits - that is, the highest f-number.

Aperture: An opening in a lens through which light enters. Aperture size is calibrated in f-numbers. The larger the f-number(ex.f11, f16) the smaller the opening size.

A small aperture has a relatively high f-number, such as f8 or f11, and a larger aperture has a smaller number, such as f2.8. The aperture setting must be balanced against the shutter speed.

Maximum aperture diameter, or minimum f-number, of a lens controlling the amount of light admitted through the lens
LED
Light Emitting Diode.

Could you please calculate the minimum and maximum f-number of the human eye. Assume a focal length of 22mm, a minimum diameter of 2mm, and a maximum diameter of 7mm.

lens speed
the largest lens opening (smallest f-number) possible for a specific lens. (A fast lens transmits more light by way of a larger opening than a slow lens).

(Fast here means that the lens can open its aperture wide - the lower the f-number (e.g. 1.8) the wider the aperture is open.

The opening in a camera lens through which light passes to expose the film. The size of aperture is either fixed or adjustable. Aperture size is usually calibrated in f-numbers-the larger the number, the smaller the lens opening.

The variable-sized hole in the diaphragm is known as the aperture, is analogous to the pupil of the eye, and is indicated numerically by an f-stop or f-number value.

The number represents the focal length of the lens divided by the diameter of the aperture. So an aperture that is 10mm in diameter in an 80mm lens will have an f-number of f/8 and the setting f/16 on the same lens will be 5mm across.

While you're at it, switch to aperture-priority mode and set it as wide as possible -- that is, to lower f-numbers (bigger stops). Finally, turn off the LCD. Those extra precautions should buy you some extra shots.

(I've done it enough to know.) To make matters worse, the depth of field (the range of distances in focus) gets shallower as you move in closer. It also gets shallower for larger apertures (lower f-numbers), ...

Aperture size is calibrated in f-numbers. The larger the number, the smaller the lens opening.
ASA film speed: The speed of a film expressed in arithmetic values determined by American Standard Association.

See also: Aperture, Light, Photograph, Camera, Lens

Topic: Photography