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Macro Lens
Macro photography (or photomacrography or macrography, and sometimes macrophotography) is extreme close-up photography, usually of very small subjects and living organisms like insects, in which the size of the subject in the photograph is greater than life-size (though ''macrophotography'' also refers to the art of making very large photographs). By the original definition, a macro photograph is one in which the size of the subject on the negative or image sensor is life-size or greater. In some senses, however, it refers to a finished photograph of a subject that is greater than life-size. The ratio of the subject size on the film plane (or sensor plane) to the actual subject size is known as the reproduction ratio. Likewise, a macro lens is classically a lens capable of reproduction ratios of at least 1:1, although it often refers to any lens with a large reproduction ratio, despite rarely exceeding 1:1. Apart from technical photography and film-based processes, where th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Macrograph
A macrograph or photomacrograph is an image taken at a scale that is visible to the naked eye, as opposed to a micrographic image, taken with a microscope. It is sometimes defined more precisely as an image at a scale of less than ten times magnification. Materials science This term is often applied to a three-dimensional image taken of a material using a low-power stereomicroscope. These images are used in materials science, particularly in the study of stress fractures in metals. This method can also be used to assay the fine structure of steel, in a standardized test called the Baumann method that creates a sulfur print showing the amount and distribution of sulfur inclusions through the metal structure.Arthur J. McEvily (2001Metal Failures: Mechanisms, Analysis, PreventionWiley-IEEE p 90 References Laboratory techniques Materials science {{photo-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Extension Tube
An extension tube, sometimes also called a closeup tube or an extension ring, is used with interchangeable lenses to increase magnification. This is most often used in macro photography. Construction The tube contains no optical elements; its sole purpose is to move the lens further from the image plane. The further away the lens is, the closer the focus, the greater the magnification, and also the greater the loss of light (requiring a longer exposure time). Lenses classically focus closer than infinity by moving all optical elements further from the film or sensor; an extension tube simply enables this movement. Since extension tubes do not have optics, they do not affect the optical quality of a lens. Due to their function, there are other effects: decrease of light; shallower depth of field; and loss of ability to focus at infinity. The longer the extension tube, the closer the lens can focus. Correspondingly, the amount of light and depth of field will be reduced. On ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Binocular Microscope
A binoviewer is an optical device designed to enable binocular viewing through a single objective. In contrast to binoculars, it allows partially stereoscopic viewing and partially monocular viewing, this because the eyes and brain still process the image binocularly, as both images are produced by the same objective and do not differ except for aberrations induced by the binoviewer itself. A binoviewer consists of a beam splitter which splits the image provided by the objective into two identical (but fainter) copies, and a system of prisms or mirrors that relay the images to a pair of identical eyepieces. Binoviewers are a standard component of laboratory microscopes and are also used with optical telescopes, particularly in amateur astronomy Amateur astronomy is a hobby where participants enjoy observing or imaging celestial objects in the sky using the Naked eye, unaided eye, binoculars, or telescopes. Even though scientific research may not be their primary goal, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Image Noise
Image noise is random variation of brightness or color information in images. It can originate in film grain and in the unavoidable shot noise of an ideal photon detector. In digital photography is usually an aspect of electronic noise, produced by the image sensor of a digital camera. The circuitry of a Image scanner, scanner can also contribute to the effect. Image noise is often (but not necessarily) an undesirable by-product of image capture that obscures the desired information. Typically the term “image noise” is used to refer to noise in 2D images, not 3D images. The original meaning of "noise" was "unwanted signal"; Noise (radio), unwanted electrical fluctuations in signals received by AM radios caused audible acoustic noise ("static"). By analogy, unwanted electrical fluctuations are also called "noise". Image noise can range from almost imperceptible specks on a digital photograph taken in good light, to Optical astronomy, optical and Radioastronomy, radioast ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photographic Filter
In photography and cinematography, a filter is a camera accessory consisting of an optical filter that can be inserted into the optical path. The filter can be of a square or oblong shape and mounted in a holder accessory, or, more commonly, a glass or plastic disk in a metal or plastic ring frame, which can be screwed into the front of or clipped onto the camera lens. Filters modify the images recorded. Sometimes they are used to make only subtle changes to images; other times the image would simply not be possible without them. In monochrome photography, coloured filters affect the relative brightness of different colours; red lipstick may be rendered as anything from almost white to almost black with different filters. Others change the colour balance of images, so that photographs under incandescent lighting show colours as they are perceived, rather than with a reddish tinge. There are filters that distort the image in a desired way, diffusing an otherwise sharp image, add ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Perspective Control Lens
Perspective may refer to: Vision and mathematics * Perspectivity, the formation of an image in a picture plane of a scene viewed from a fixed point, and its modeling in geometry ** Perspective (graphical), representing the effects of visual perspective in graphic arts ** Aerial perspective, the effect the atmosphere has on the appearance of an object as it is viewed from a distance ** Perspective distortion (photography), the way that viewing a picture from the wrong position gives a perceived distortion ** Perspective (geometry), a relation between geometric figures ** Vue d'optique or perspective view, a genre of etching popular during the second half of the 18th century and into the 19th. Film and television * ''Perspective'' (film series), a 2012–2020 Canadian film series by B. P. Paquette * ''Perspective'' (2019 film), an American adult romance drama * ''Perspectives'' (TV series), a 2011–2016 British arts documentary series Music * Perspective Records, an American r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
View Camera
A view camera is a large format, large-format camera in which the large format lens, lens forms an erect image, inverted image on a ground glass, ground-glass screen directly at the film plane. The image is viewed, composed, and focused, then the glass screen is replaced with the photographic film, film to exposure (photography), expose exactly the same image seen on the screen. This type of camera was developed during the era of the daguerreotypeStroebel, L. D. (1986). ''View Camera Technique'', 5th ed., p. 212. Boston: Focal Press. (1840s–1850s) and is still in use, some using drive mechanisms for movement (rather than loosen-move-tighten), more scale markings, and/or more spirit levels. It comprises a flexible bellows (photography), bellows that forms a light-tight seal between two adjustable ''standards'', one of which holds a Photographic lens, lens, and the other a ground glass or a photographic film holder or a digital back.Stroebel (1986). p. 2. There are three gen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scheimpflug Principle
The Scheimpflug principle is a description of the geometric relationship between the orientation of the plane of Focus (optics), focus, the lens plane, and the image plane of an optical system (such as a camera) when the lens plane is not parallel to the image plane. It is applicable to the use of some View camera#Movements, camera movements on a view camera. It is also the principle used in corneal pachymetry, the mapping of corneal topography, done prior to refractive eye surgery such as LASIK, and used for early detection of keratoconus. The principle is named after Austrian army Captain Theodor Scheimpflug, who used it in devising a systematic method and apparatus for correcting Perspective (visual), perspective distortion in aerial photographs, although Captain Scheimpflug himself credits Jules Carpentier with the rule, thus making it an example of Stigler's law of eponymy. Description Normally, the lens and image (film or sensor) planes of a camera are parallel, and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
View Camera
A view camera is a large format, large-format camera in which the large format lens, lens forms an erect image, inverted image on a ground glass, ground-glass screen directly at the film plane. The image is viewed, composed, and focused, then the glass screen is replaced with the photographic film, film to exposure (photography), expose exactly the same image seen on the screen. This type of camera was developed during the era of the daguerreotypeStroebel, L. D. (1986). ''View Camera Technique'', 5th ed., p. 212. Boston: Focal Press. (1840s–1850s) and is still in use, some using drive mechanisms for movement (rather than loosen-move-tighten), more scale markings, and/or more spirit levels. It comprises a flexible bellows (photography), bellows that forms a light-tight seal between two adjustable ''standards'', one of which holds a Photographic lens, lens, and the other a ground glass or a photographic film holder or a digital back.Stroebel (1986). p. 2. There are three gen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diopter
A dioptre ( British spelling) or (American spelling), symbol dpt or D, is a unit of measurement with dimension of reciprocal length, equivalent to one reciprocal metre, . It is normally used to express the optical power of a lens or curved mirror, which is a physical quantity equal to the reciprocal of the focal length, expressed in metres. For example, a 3-dioptre lens brings parallel rays of light to focus at metre. A flat window has an optical power of zero dioptres, as it does not cause light to converge or diverge. Dioptres are also sometimes used for other reciprocals of distance, particularly radii of curvature and the vergence of optical beams. The main benefit of using optical power rather than focal length is that the thin lens formula has the object distance, image distance, and focal length all as reciprocals. Additionally, when relatively thin lenses are placed close together their powers approximately add. Thus, a thin 2.0-dioptre lens placed close to a th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bridge Camera
A bridge camera is a type of camera that fills the niche between relatively simple point-and-shoot cameras and interchangeable-lens cameras such as mirrorless cameras and single-lens reflex cameras (SLRs). They are often comparable in size and weight to the smallest digital SLRs (DSLR), but lack interchangeable lenses, and almost all digital bridge cameras lack an optical viewfinder system. The phrase "bridge camera" has been in use at least since the 1980s, and continues to be used with digital cameras. The term was originally used to refer to film cameras which "bridged the gap" between point-and-shoot cameras and SLRs. Like other cameras, most current bridge cameras are digital. These cameras typically feature full manual controls over shutter speed, aperture, ISO sensitivity, color balance and metering. Generally, their feature sets are similar to consumer DSLRs, except for a smaller range of ISO sensitivity because of their typically smaller image sensor. Many b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acutance
In photography, acutance describes a subjective perception of visual acuity that is related to the edge contrast of an image. Acutance is related to the magnitude of the gradient of brightness. Due to the nature of the human visual system, an image with higher acutance appears sharper even though an increase in acutance does not increase real resolution. Historically, acutance was enhanced chemically during development of a negative (high acutance developers), or by optical means in printing ( unsharp masking). In digital photography, onboard camera software and image postprocessing tools such as Photoshop or GIMP offer various sharpening facilities, the most widely used of which is known as "unsharp mask" because the algorithm is derived from the eponymous analog processing method. In the example image, two light gray lines were drawn on a gray background. As the transition is instantaneous, the line is as sharp as can be represented at this resolution. Acutance in the l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
