the distance from the center of a lens to the focal point (the point where light striking the lens parallel to the optical axis is focused)
The distence from a mirror or lens at which the light rays being focused are brought to a common point, and (in a telescope) an image is formed. If you've ever focused the sun's rays with a magnifying glass, the distance from the lens at which the rays are most concentrated is the focal length of the lens.
The distance from the camera at which an object comes into focus.
The distance betwen 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.
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.
measured from mirror surface to a point where a reflected image is formed.
The distance from a lens to the focal point, that is, the point where the light rays converge inside the camera.
The distance from the center of a lens (or mirror) to the point at which light converges to a point (or focus).
The distance between the focal point and the vertex of a mirror or lens. For concave mirrors and convex lenses, this number is positive. For convex mirrors and concave lenses, this number is negative.
Distance from the exact center of the dish to the center of the feed.
The distance in mm from the focal point of a lens to the principal point of the lens.
A measurement of the size of a lens, usually in millimeters. Larger lenses produce increased image magnification.
The distance, usually given in millimeters, between the optical center of a lens and the point at which rays of light from objects at infinity are brought to focus. In general, the greater the focal length, the smaller and more magnified the part of the scene, it includes in the picture frame.
(1) Distance from the center of the lens to the film plane. (2) Size of lens required to obtain a specific size picture.
distance between the optical center of a lens focused at infinity and the film plane. Understanding Focal Length
The amount of distance between the actual lens and the image sensor.
The distance from the objective lens or mirror to the point where the light converges, the focal point. This distance is usually measures in millimeters.
a term used in general photography for the distance between the rear principal point of the lens and the rear focal point when the lens is focused on infinity.
Distance from a camera's lens to a focused image with the lens focused on infinity. Short focal lengths offer a broad field of view (wide-angle); long focal lengths offer a narrow field of view (Telephoto). Zoom lenses have a variable focal length.
the distance from the focal point of a lens or mirror to the surface of the lens or mirror.
The distance between the lens and its focal point. Also the value given to a lens, stated in inches or millimeters. The smaller the focal length, the wider the angle of the image.
The distance measured along the optical axis of a lens from the optical center (rear nodal point) to the plane of critical focus of a very distant object.
The distance measured from the film to a point in the lens optics when the lens is focused at infinity. It describes the angle of view of the lens and plays a major role in determining how much of a scene will be recorded on film.
Lens view measurement. A wide view lens (wide-angle) has short focal length and a long view lens (telephoto) has longer focal length.
The optical property of a lens. In projection terms, the smaller the focal length, the larger the projected image is likely to be.
Measure (in millimetres) of the magnification and angle of view of a given lens setting. Focal length is also dependent on CCD size, so the focal length of different camcorders can only be directly compared if they have the same size CCD.
The distance measured along the optical axis from the optical centre (rear nodal point) of the lens to the plane of critical focus of a very distant object.
The distance of a focus from the surface of a lens or concave mirror. Relates to the distance between an image source and a lens and the distance of the lens to the image.
The distance from the center of a lens to the focal point (in this case, the image sensor). The longer the focal length the narrower the angle of view. Because a digital image sensor is much smaller than the surface of 35-mm film, a digital camera's focal length is shorter than that of a comparable film camera. That's why digital camera makers often list lenses in 35-mm equivalent focal lengths.
The distance from the reflective surface of a parabola to the point at which incoming satellite signals are focused, the local point.
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 1/4”, 1/3”, or 1/2”.
The distance between a lens' surface and the focal point.
Focal length, measured in millimetres, it is defined as the distance from the optical center of the lens to a focal point near the back of the lens. It indicates the field of view produced by the lens. Fixed focal length lenses are available in various wide, medium, and narrow fields of view. A lens with a normal focal length produces a picture that approximates the field of view produced by the human eye. A wide-angle lens has a short focal length, while a telephoto lens has a long focal length. A fixed focal lens has a constant focal length, while a varifocal or zoom lens can change its focal length.
The distance between the optical center of a lens and the point of focus, usually represented in mm or inches
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 should also be noted that different cameras (photographic cameras, different imager sizes in video cameras, etc.) will deliver different viewing angles with the same focal length lens.
Focal length is the distance between the lens and its focal point. A smaller focal length indicates a wider-angle lens.
The distance from the center of the lens to the point where it focuses light. The combination of focal length and CCD format determines a camera's field of view. The shorter the focal length, the wider the field of view.
A property of a lens or mirror, equal to the distance from the lens or mirror to the image it forms of an object that is infinitely far away.
The distance from the centre of the mirror to the F. This is 1/2 the distance of the radius.
The distance from the focal point or center of the lens to the focal plane or image pick-up device and usually expressed in millimeters (mm). The larger the number the longer the lens and the more telephoto the field of view.
A good definition for our needs, while not technically precise, is that Focal Length is the distance from the optical center of the lens to the film plane, CCD, or CMOS of a digital camera. The precise optical definition is: The distance from the plane in which the lens forms an image at infinity to the node of emission. The focal length is usually on the lens and appears as: f=100mm. This is a focal length, f, of 100 millimeters.
The nearest distance a lens can be from the film when focused on a distant object. The longer the focal length, the larger the image scale.
Distance from the center of a lens to the surface of a CCD measured in millimeters, centimeters, or inches. Long focal lengths have small-angle views. Short focal lengths have wide-angle views.
is the distance from the lens to the surface of the film or CCD sensor (the plane of focus) where the light rays come together. The term is used to refer to the size of a lens; thus, a telephoto lens is of greater focal length than a wide angle lens.
The focal length of a lens indicates its angle of view. Focal length is measured in millimetres and the smaller the number the wider the angle of view. For a 35mm (film size) camera, 5Omm or 55mm is the focal length of the standard lens. Less than 5Omm means a wide angle lens and more than 5Omm means a telephoto lens.
Distance between the focal plane and lens of a camera.
The length at which parallel rays of light are brought into focus for a particular lens or mirror.
The 'length' of a lens - usually measured from the image (slide, film or TFT panel) to the front surface of a lens. This is directly related to the image size and the projection distance.
refers to the distance between the optical center of the lens and the focal plane, when the focus is set at infinity. The focal length is usually measured in millimeters.
Measured in millimeters or inches, this length refers to the distance between the center of the lens to the surface of the camera imaging device (CCD). Long focal lengths have small angles of view, while short focal lengths have wide angles of view.
The distance between the lens and image when focused for a distant subject.
for parallel incident rays, the distance between an optical element (lens, mirror) and the focal point where all rays converge.
Describes the magnification and field of view of a cameras lens.
The focal length is the length of the path through a telescope which incoming light follows. The magnification of a telescope is determined in part by the focal length of the scope.
Distance between the center of a lens and the point on the optical axis to which parallel rays of light are converged by the laser.
The distance from the lens to the film plane of a camera. The focal length determines the size and perspective of the image produced. A wide angle lens has a short focal length, a telephoto lens has a long focal length.
The size of the angle of view of the lens, measured in millimeters. The smaller the number, the wider the lens. Zoom lenses have a range of focal lengths.
The distance between the last surface of a lens, or the front surface of a curved mirror, and the focal plane.
the distance from lens to the screen when the image of a distant object is in focus. This governs how large the image is - the longer the focal length, the larger the image. (Sometimes referred to as 'Focal Distance').
The focal length of the lens provides an indication of how much magnification your lens provides, and at what angles it can shoot. Manufacturers quote actual focal length in millimeters, usually as a range, such as 7 to 25mm. The higher the number, the greater the magnification; the smaller the number, the wider the angle of view. Because many users are more familiar with the angles and magnifications offered by a given focal length with 35mm cameras, manufacturers also quote focal length in 35mm equivalencies.
The distance between the centre of the antenna reflector and a point where the received signals are focused.
Distance from rear nodal point of a lens to the rear principal focus when lens is focused on infinity. Reciprocal of focal length is the power of a lens.
The focal length on a digital camera is usually related to the 35mm equivalent, due to the fact that the CCD's on digital cameras are much smaller than the areas exposed on a 35mm camera. So a camera that states that it has a 38mm lens is really reffering to the 35mm equivalent, even though the actual lens may only be around a 6mm lens.
This is the effective length of the path which the light must follow through a telescope. In a refractor or Newtonian design the focal length is equal to the actual length of the light path from the primary mirror to the focus point (where a CCD would be placed). In a Cassegrain type of telescope, the effective focal length is usually about 5 times longer than the actual length of the light path due to the magnifying effect of the secondary mirror.
The distance between the nadir (center) point of the photographic lens to the photographic plane. Typical focal lengths are 153mm (6") and 305mm (12").
The basic parameter to determine the image position, magnification, and angle of view of a lens.
The focal length of a lens is the distance from the centre of the lens to the in focus image of a distant subject.
The distance from the center of the lens to an object at a infinite distance from the camera that comes into focus.
When focus is set at infinity, it is the distance from the rear nodal point of the lens to the focal plane.
The distance, measured in millimetres defines the distance from the lens to the plan of focus.
The distance between the back lens element and the focal plane. In 35mm format, lenses with a focal length of approximately 50mm are called normal (standard), lenses with approximately 35mm or less are called wide-angle, and lenses with a focal length of more than approximately 70mm are called telephoto lenses.
The distance from the primary objective to the focal point in an optical system.
The distance from the surface of a lens to its focal point.
Of a lens, the distance from the focal point to the principal point of the lens.
The distance from the centerline of the lens to the camera pick-up device. The focal length determines the size of the image and the angle of the field of view as seen by the camera through the lens.
The distance between the optical center of a lens and the image plane (which in the case of a video camera (or digital still camera) is the CCD target area). The focal length is measured in millimeters and determines both the magnification and the angle of view of a lens. On a variable focal length lens or zoom lens this measure can be adjusted between two preset focal length extremes. In the case of digital still cameras, Sony quotes not only the actual focal length, but also the 35mm film camera equivalent.
The distance between the optical center of a lens and the principal convergent focus point.
The distance from a lens or mirror to the point at which rays from an object at infinity are focused.
The value given to a lens, stated in inches or millimeters. The smaller the focal length, the wider the angle of the image. Focal length is the distance between the lens and its focal point.
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.)
It is the distance between the central point of a lens and the point where the beams are bundled (focal point). The bigger the focal length the closer targeted objects appear to be on the image.
A lens' angle of view, most commonly indicated as wideangle, normal or telephoto. Usually compared to a 35mm camera's lenses as in "the camera has a wideangle lens equivalent to a 38mm lens on a 35mm camera." See also "Zoom Lens"
The focal length is the distance between the center of a lens and the focal point. The greater the focal length, the closer objects in the picture appear. The focal length of an object (usually given in millimeters) depends on the size of the display window. The larger the focal length, the more enlarged the image will appear whilst decreasing the angle of view. This principle is visible in binoculars, where a large focal length allows distant objects to be 'brought' closer.
is the distance from the optical center of a lens to the point where light rays converge (are in focus). Shorter focal lengths correspond to a wider field of view and vice versa, i.e., a "telephoto" lens has a longer focal length.
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. See also normal lens, telephoto lens, wide-angle lens.
A measurement of the magnification of a lens indicated in millimeters.
distance light rays travel after refraction to the point of focus
The distance, usually measured in millimeters, between the lens and the focal plane in a camera. As the focal length increases, the field of view decreases.
Distance from the optical center of the back surface of the eye to the principal focus of the lens. Go to Top
the distance, measured in millimetres, between the optical centre of a lens and the CCD chip when a distant subject is in focus.
The distance, in millimetres, between the centre of a lens and the plan of focus (film plane). This distance is measured with the lens focused at infinity.
The distance along the optical axis from the image to the plane where the backwards-extending axial imaging cone of light intersects the extended incoming light cone.
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).
A fundamental measure of lens performance, usually expressed in millimeters.
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 (in millimeters) from the lens to the surface of the image sensor. The shorter the distance, the wider the view; the longer the distance, the narrower (telephoto) the view.
The distance from optical center of a lens to the surface of the exposure plane. This is usually measured in millimeters. The longer the focal length is the more narrow the angle of view, the more objects are magnified. Normal focal length lens provides about the same angle of view, as the photographer would see it.
is the distance between the optical centre of a lens and the point of focus. It is usually measured in mm or inches.
The distance from the reflective surface of an antenna to its focal point, usually measured in the horizontal plane. Incoming satellite signals are directed to the Feedhorn which is normally located at the focal point. See also f/D ratio.
In photography, the distance measured along the optical axis from the optical centre of the lens to the film plane, measured when the lens is focused at infinity.
In cameras, the distance measured along the optical axis from the optical centre of the lens to the plane at which the image of a distant object is brought into focus.
the distance between the optical centre of a lens and the 'focal point' (the point at which parallel light rays entering the lens come into focus). Focal length is measured in millimetres. The shorter the focal length, the wider the angle of view of the lens. Most camcorders have zoom lenses, which allow you to vary the focal length.
Distance from the centre feed to the centre of the dish.
The distance from a lens' principal point to the corresponding focal point on the object.
The distance from a lens or mirror to the point where light converged by it comes to a focus.
Loosely, the focal distance when the lens is focused on infinity; more accurately, the distance from the rear nodal point of the lens to the image plane when the lens is focused on infinity.
The distance from the plane of infinite focus to the center of the camera lens.
The distance between the optical centre of the lens and the image sensor. The longer the focal length, the greater the magnification involved; the shorter the focal length, the wider the angle of view.
The distance from the rear model plane of a lens to the focus when the lens is focused at the infinity position.
How wide or narrow a view a particular lens will provide.
The distance from the film to the optical centre of the lens when the lens is focused on infinity. Focal length on most adjustable cameras is marked in millimetres on the lens mount. On 35mm-format cameras, lenses with a focal length of 50mm are called normal or standard lenses. Lenses of 35mm or less are called wide angle lenses and lenses of 85mm or more are called telephoto lenses. Lenses which allow varying focal lengths without changing focus are called zoom lenses .
The distance light travels from the primary lens or mirror to where it converges or is focused.
The distance from the objective lens or mirror to the place where the image is focused.
The distance from an internal part of a lens (the rear nodal plane) to the film plane when the lens is focused on infinity. The focal length is usually expressed in millimeters (mm) and determines the angle of view (how much of the scene can be included in the picture) and the size of objects in the image. A 100mm lens, for example, has a narrower angle of view and magnifies objects more than a lens of shorter focal length.
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 in millimeters (mm). A particular lens' focal length can generally be found engraved or printed on the front of the lens.
Focal length is a measure of the distance from a camera's lens to the focal point. Because digital cameras' focal lengths are measured differently than traditional film cameras, manufacturers usually give a "35mm equivalent" focal length in their specs. A typical digital camera's 35mm equivalent focal length might be 35-120mm. With a long focal length, like 300mm, a camera is better able to capture far-off subjects (such a lens is also known as " telephoto"). With a short focal length, like 28mm, a camera can capture the scene immediately before it more completely (this kind of lens is considered " wide-angle").
The distance between the film or sensor and the optical center of the lens when the lens is focused on infinity. The focal length of the lens on most adjustable cameras is marked in millimetres on the lens mount. In 35mm-format cameras, lenses with a focal length of approx. 50mm are called normal or standard lenses. Lenses with a focal length less than approx. 35mm are called wide angle lenses, and lenses with a focal length more than approx. 85mm are called telephoto lenses. Lenses which allow the user to continuously vary the focal length without changing focus are called zoom lenses.
A distance from a lens to a point where it focuses parallel rays of light.
The distance between the centre 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 field of view and greater magnification.
For telescopes it's the distance from the main lens/mirror to its focus point. The longer the distance the greater the magnification. If you are familiar with a SLR camera's 50mm lens, that is the same measurement. A 50mm lens is often considered "1 power" or "1x". A 1200mm telescope would be about 24x before any eyepieces are used to increase the magnification even more. For eyepieces it's used to determine the amount of additional magnification they provide. See Magnification.
The "size" of the lens indicated in millimeters. The "normal" focal length of super-8 film is about 14,5 mm. It means that at this length camera sees the world pretty much like a human eye. Shorter length is called "wide angle". It shows much wider range, but an extreme wide angle can distort the image. The shortest focal length found in super-8 cameras is 6 mm, although some cameras (e.g. some models from Eumig and Bolex) can achieve 4 mm length with separate wide angle attachment. Longer than normal focal length is called "tele". It magnifies the image and brings it closer, but also flattens it, and makes the picture less steady. Longest tele found in super-8 cameras with fixed lens is 90 mm.
Inside a camera, the distance from the lens's focal point (its optical center) to its focal plane (where the image falls on the CCD imaging chip) with the lens focused on infinity. Short focal lengths offer a broad field of view (wide-angle); long focal lengths offer a narrow field of view (telephoto). Zoom lenses have a variable focal length.
The distance from the surface of the lens to the focal point or center point at which light rays converge; the focal length determines the length of the lens.
Focal length, in millimeters, it is defined as the distance from the lens to a point where parallel rays are focused to a point (diverge). The focal length of a typical digital camera lens is a small number such as 6 - 15mm. Because the sensor in a digital camera is much smaller than a 35mm negative the lenses can be made smaller. To get the true focal length you need to multiply this small size by a value called the "focal length multiplier".
The distance between the film or CCD sensor and the lens' focal point. Normal focal length gives an image impression roughly corresponding to that of the human eye (about 50 mm in conventional film cameras and about 7 mm in digital cameras with 1/3" CCD).
The distance from a lensÂf principal point to the corresponding focal point. Also referred to as the equivalent focal length and the effective focal length; e.g. a 50mm lens.
Of a Lens, measured in Millimetres. Has a direct relationship with angle (or field) of view of the camera. The smaller the focal length, the wider the field of view.
Distance from the center feed to the center of the dish.
Distance from a lens or concave mirror to where converging light rays meet.
The distance between a lens or mirror and its focal point. This length is usually stated in terms of the diameter of the lens or mirror; for example, a reflecting telescope of focal length f/4 has a focal length that is four times larger than the diameter of the primary mirror. Generally, longer focal lengths permit higher magnification, but smaller fields of view.
The distance between a focal point of a lens or mirror of projection equipment and the corresponding principal plane. Shorter focal length means larger image size on the screen for given projection distance.
the distance from the lens to the focal plane when the lens is focused on infinity. The longer the focal length, the greater the magnification of the image
The distance from a lens to its focus.
The distance from the center of the lens to a plane at which point a sharp image of an object viewed at an infinite distance from the camera is produced. The focal length determines the size of the image and the angle of the field of view seen by the camera through the lens. That is the distance from the center of the lens to the pickup device.
Photographic lenses are measured using a term called focal length. This refers to "size" of the lens, or the size of the image it will produce. Wide angle lenses produce a picture that includes a broad image - telephoto lenses help make faraway objects look closer.
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.
The distance of the focal point from the lens.
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 between the lens and the focal point. Shorter focal length means larger image size on the screen for given projection distance.
The distance between the surface of the camera lens and the sensor array at the back of the camera. The focal length of the camera determines how large the subject appears.
a number that represents the length of a lens. Longer focal lengths produce greater magnification than shorter focal lengths. "Normal" lenses for 35mm cameras are in the 35mm to 60mm range. Longer than 60mm is considered "telephoto," while shorter than 35 is considered "wide angle." Lenses shorter than 24mm are often considered "extreme wide angle."
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 between the lens and its principal focus.
Distance from the focal point (feed) to the center of the parabolic antenna.
The distance from the optical center of the lens to the image sensor when the lens is focused on infinity. The focal length is usually expressed in millimeters (mm) and determines the angle of view (how much of the scene can be included in the picture) and the size of objects in the image. The longer the focal length, the narrower the angle of view and the more that objects are magnified.
The distance from the convergent point for the radiation (focal point) to its affiliated principal plane.
in a refracting telescope, the distance from the center of the primary lens at the end of the tube to where light is focused to a point. See the Astro 201 page on telescopes.
In photography, the distance from the center of the lens to the image of an object at infinity. At same size, the distance from copy to image is four times the focal length of the lens. This also applies to lithographic process lens as well.
Focal length is the distance from the lens (or mirror) in a telescope to the point at which the object being observed is focused.
The distance needed between a lens and an object to make the object visible and in focus. The human eye has different focal lengths depending on how much the muscles in the eye around the lens are contracted. That is how the human eye focuses.
A lens comprises multiple lens elements, it can be regarded as a single convex element. The focal length is defined as the distance from the center of such a convex element (principle point) to the focal point (image plane) and it is one of the most decisive factors that determines the characteristics of a lens.
distance between the rear nodal point of the lens and the focal plane, when the focus is at infinity.
This is the distance between the lens's focal point and the film plane when the lens is focused at infinity. Focal length is used to tell you the relative size and angle of view of the lens. It is expressed in millimeters. Your lens's focal length is usually printed or engraved on the front of the lens.
The focal length is the distance from the front element of a lens to the sensor (or negative). The focal length can be used to describe the effect that the lens has on the produced image. A long focal length (say, 50mm and up) make objects look closer (like a telescope). Short focal lengths (24mm and smaller) capture a wider view, making object smaller. Lenses with short focal lengths are sometimes refered to as wide angle.
The focal length of your lens is described in millimetres such as 50mm. This tells you how much of a scene you can capture. Wide angles have shorter focal lengths eg 28mm which allow you to fit a lot into your picture. Telephoto lenses have longer focal lengths eg 100mm which allow you to bring distant objects closer to you.
Technically the distance in millimetres between where light from infinity is focused and the optical centre of the lens. A 35mm SLR camera has interchangeable lenses that can range in focal length from around 7 to 17mm which are usually fisheye, 17 to 35 are considered wide angle. 50mm is called the standard lens as it has the same equivalent focal length as the human eye. Anything longer is a telephoto lens.
An indication of how wide or narrow a section of the scene is included in a picture (angle of view), and/or how big or small it makes the subject (magnification).
The focal length of an optical system is a measure of how strongly it focuses or diverges light. A system with a shorter focal length has greater optical power than one with a long focal length.