The distance from the optical center of a lens to the point at which parallel rays of light passing through it converge (the focal point).

Focal length is the distance between the focal point of a lens and the film plane when the lens is focused at infinity. It is used to designate the relative size and angle of view of a lens, expressed [..]

is the distance from the lens to the image focus point inside the camera. A high focal length makes distance objects appear magnified while a low focal length give a wide view of the scenery facing th [..]

The distance from the principal point to the focal point. Read articles that include this term

Focal length (shown in orange) is the distance between the center of a convex lens or a concave mirror and the focal point of the lens or mirror – the point where parallel rays of light meet, or conve [..]

The lens-to-focal-plane distance at the infinity setting. Focal length affects shooting distance, which affects Perspective. See: Angle of View.

Focal length (shown in red) is the distance between the center of a convex lens or a concave mirror and the focal point of the lens or mirror — the point where parallel rays of light meet, or converge [..]

In digital photography and digital video recording, the focal length refers to the size of the image and angle of  field of view as seen by the camera through the lens. This is the center of the lens [..]

Name given to the distance between the surface of a lens and the point at which it focuses the light passing through the lens and is shown as the f stop.

Simply put, how wide or narrow a view the lens will provide, smaller numbers being wider and larger numbers being narrower.

The distance (usually expressed in millimeters) from a mirror or lens to the image that it forms. In most telescopes the focal length is roughly equal to the length of the tube. Some telescopes use extra lenses and/or mirrors to create a long effective focal length in a short tube.

(working distance) the distance from the object at which the objective lens is in focus. Covered in BIOL1020 Lab 1 Introduction to the Laboratory

The distance from the vertex of a mirror or lens to the focal point.

The distance between the principal focus of a lens or mirror and its optical center or vertex.

The focal length of lens is measured in metres. It is the distance from the centre of the lens to the point at which rays passing through the lens meet (i.e. focus). It is related to lens power.

a measure of how strongly an optical system focuses or defocuses light

HP, SP The focal length of lens is measured in metres. It is the distance from the centre of the lens to the point at which rays passing through the lens meet (i.e. focus). It is related to lens powe [..]

The focal length of a lens or mirror is the distance from the optic at which incoming parallel light will converge to a single point in space. The narrowness of the band of colors that a spectrometer can generate is directly related to the focal length of its collimating mirrors. A longer focal length in an optical system will result in higher opti [..]

(n.) The distance from a lens or mirror to the point at which rays from an object at infinity are focused.

The distance from the optical center of the lens to the image of an object located at an infinite distance from the lens. Long focal lengths give a small field of view (e.g. telephoto effect), while short focal lengths give a wide angle view.

The distance between the center of a lens, or its secondary principal point and the imaging sensor. Lower lengths give a greater field of view and less magnification. Longer lengths give a narrower fi [..]

Imaging Device Size

FL. The distance from the center of a lens (or, the secondary principal point, if it has) to the focal point (sensor). The longer the focal length, the narrower is the angle of view.

A lens’ angle of view. Such as Wide angle, standard or telephoto.

Distance from the centre feed to the centre of the dish.

indicates the distance between the optical center of a lens and a video camera's image sensor device. For practical purposes, lens focal length refers to a camera's angle of view. Lenses with a higher focal length number have more narrow, telephoto fields of view. A very low number focal length indicates a very wide field of view. It shou [..]

An optical measurement that determines how much of what you see in front of you is captured by your camera's lens. A short focal length, such as 24mm, captures wide angle; a long focal length, su [..]

The distance from the lens to the film plane or sensor that focuses light at infinity. The length, expressed in millimeters, is more useful as an indication of the angle of view of a particular lens. A shorter focal length lens, such as a 28mm, offers a wider angle of view than a longer one, such as 100mm.

The distance from the middle of a lens to the image sensor.

The distance in millimeters from the optical center of a lens to the imaging sensor when the lens is focused at infinity. The focal length relays both the angle of view and the magnification. The long [..]

Measured in millimeters, the focal length of a camera lens determines the width of the horizontal field of view, which in turn is measured in degrees.

How wide or how narrow a view the lens will provide. Smaller focal length numbers mean wider; larger numbers mean narrower.

The distance from the optical center of a lens to the image plane when the lens is focused to infinity.  

Focal length is measured in mm or inches, and is the distance between the optical center of the lens and the point on which it focuses.  A lower focal length results in less magnification with a greater field of view, and vice versa for longer focal lengths.  Security cameras usually have a focal length of ¼”, 1/3”, or ½”.

The distance from the middle point of the lens to the focus point. Assuming that the camera's position is fixed, the larger this value becomes, the larger the subject appears (telephoto). Conversely, the smaller this value becomes, the smaller the subject becomes (wide angle).

The distance between a lens and its focal point; it usually expressed in millimeters. A system with a shorter focal length has wider fields-of-view.

The distance from the center of the lens to the point at which the light rays meet in sharp focus. The focal length determines the perspective relations of the space represented on the flat screen. Other terms to explore: Normal lens, Telephoto lens, and Wide-angle lens.

The focal length is the physical distance between the center of the lens and the focal point, which is the image sensor on a digital camera. As focal length increases, the magnification of the image i [..]

Indicates the magnification and angle-of-view of a lens. The human eye sees things roughly the same as a 43mm focal length of a lens for a 35mm camera. Anything shorter is classed as a wide-angle, whi [..]

Technical term indicating how wide or narrow a section of a scene the lens includes in a picture (angle of view), and/or how big or small it makes the subject (magnification).

the distance from the optical centre of the lens to the point just behind the lens where the image is in sharp focus, while the focus is set to infinity. Long focal lengths bring distant objects up cl [..]

The distance from the optical center of a lens to the point at which parallel rays of light passing through it converge (the focal point).

The distance from the lens or mirror in an optical system and the focal plane where the light is focused.

Of a lens, the distance from the focal point to the principal point of the lens.

The distance from the center of the lens to a plane at which point a sharp image of an object viewed at an infinite position. The focal length determines the size of the image and angle of FOV seen by [..]

Measured in millimeters, the focal length of a camera lens determines the width of the horizontal field of view, which in turn is measured in degrees.

Focal Length is the Principal Distance when the lens of the camera is focused at infinity. Also see Principal Distance.

The distance from the optical center of a lens to the image plane when the lens is focused to infinity.

Focal Length is the specific length of the lens' frontal glass element going back to the rear element, measured in millimeters. Focal length of a lens also dictates the various image properties of a lens (i.e. a short, wide angle lens has completely different properties than a long, telephoto lens). The focal length also determines the amount [..]

The focal length of a lens determines its field of view at a given distance. A wide angle lens as its name suggests a wide field of view at a given distance. This means that it can see a wide area of [..]

A lens' angle of view, most commonly indicated as wide angle, normal or telephoto. Usually compared to a 35mm camera's lenses as in "the camera has a wide angle lens equivalent to a 38m [..]

The distance from the principal point to the focal point. Read articles that include this term

The distance between the secondary principal point in the lens and the plane of the imaging device. The longer the focal length, the narrower is the angle of view.

A measure of the refracting power of a lens, focal length is the distance between the optical centre of the lens and the image it produces of an infinitely distant object.

Measured in millimeters, focal length is the distance between the sensor and the optical center of the lens, when focused on infinity. The focal length is usually marked on the lens itself, sometimes with a range (example: 55mm-250mm). For more on focal length, see the section on lenses.

Measured in millimeters, the focal length of a camera lens determines the width of the horizontal field of view, which in turn is measured in degrees.

The distance from the focal point of a lens to the plane of the film (for viewers and cameramen, this is seen as the amount of area a lens can photograph from a given distance.)

distance between the rear nodal point

The distance between the image sensor (or film) and the centre of the lens when the lens is focused to infinity. Focal length can be used to indicate how much of a scene the lens will include.

The distance between the focal point of a lens and the film plane. This refers to the relative size of the lens (i.e 24mm, 50mm, 85mm).

the distance from a camera lens to the point where the image is in focus (focal point).

In optics and photography, the focal length is the distance from the optical center of the lens to the imaging sensor when the lens if focused at infinity. The focal length is measured in millimeters. [..]

The distance between the focal plane on the sensor and the focal point (optical centre of the lens) when the lens is focused at infinity. The focal length of the lens is marked in millimeters on the lens mount. The principal focal point is the position of best focus for infinity.

The distance of a focus from the surface of a lens (such as a camera lens) to the focal point.

Distance from a lens or mirror to the point it draws light to a focus.

Focal length (shown in orange) is the distance between the center of a convex lens or a concave mirror and the focal point of the lens or mirror – the point where parallel rays of light meet, or converge.

(optics) The distance at which something (e.g. a lens, mirror etc.) is in focus; in air it is the distance along the optical axis from a "principal plane" of the lens to one of the lens's focal poin [..]