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F-number
The f-number of an optical system (such as a camera lens) is the ratio of the system's focal length to the diameter of the entrance pupil.[1] It is a dimensionless number that is a quantitative measure of lens speed, and an important concept in photography
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Poison
In biology, poisons are substances that cause disturbances in organisms, usually by chemical reaction or other activity on the molecular scale, when an organism absorbs a sufficient quantity.[1][2] The fields of medicine (particularly veterinary) and zoology often distinguish a poison from a toxin, and from a venom. Toxins are poisons produced by organisms in nature, and venoms are toxins injected by a bite or sting (this is exclusive to animals). The difference between venom and other poisons is the delivery method. Industry, agriculture, and other sectors employ poisonous substances for reasons other than their toxicity. Most poisonous industrial compounds have associated material safety data sheets and are classed as hazardous substances. Hazardous substances are subject to extensive regulation on production, procurement and use in overlapping domains of occupational safety and health, public health, drinking water quality standards, air pollution and environmental protection
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Canon 7
The Canon 7
Canon 7
was a rangefinder system camera produced by Canon Inc., the last compatible with the Leica M39 lens mount. It was introduced in September 1961, with an integrated Selenium meter
Selenium meter
cell. Further versions, branded Canon 7s and Canon 7s Type II (or Canon 7sZ), modified the design slightly by introducing a cadmium sulfide cell. The Canon 7
Canon 7
came as the first Canon reflex cameras were already on the market, but it was felt that there was a need for a fast-shooting rangefinder camera for reportage
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Zeiss Tessar
The Tessar
Tessar
is a famous photographic lens design conceived by the German physicist Paul Rudolph in 1902 while he worked at the Zeiss optical company and patented by Zeiss in Germany; the lens type is usually known as the Zeiss Tessar. A Tessar
Tessar
comprises four elem
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Sharpness (visual)
In photography, the term "acutance" describes a subjective perception of sharpness that is related to the edge contrast of an image. Acutance
Acutance
is related to the amplitude of the derivative of brightness with respect to space. 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
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
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Optical Aberration
Tilt Spherical aberration Astigmatism Coma Distortion Petzval field curvature Chromatic aberrationAberration in optics refers to a defect in a lens such that light is not focused to a point, but is spread out over some region of space,[1] and hence an image formed by a lens with aberration is blurred or distorted, with the nature of the distortion depending on the type of aberration. More specifically, it can be defined as a departure of the performance of an optical system from the predictions of paraxial optics.[2] In an imaging system, it occurs when light from one point of an object does not converge into (or does not diverge from) a single point after transmission through the system. Aberrations occur because the simple paraxial theory is not a completely accurate model of the effect of an optical system on light, rather than due to flaws in the optical elements.[3] An image-forming optical system with aberration will produce an image which is not sharp
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Sony
Sony
Sony
Corporation (ソニー株式会社, Sonī Kabushiki Kaisha, /ˈsoʊni/ SOH-nee, stylized as SONY) is a Japanese multinational conglomerate corporation headquartered in Kōnan, Minato, Tokyo.[9][1] Its diversified business includes consumer and professional electronics, gaming, entertainment and financial services.[10] The company is one of the leading manufacturers of electronic products for the consumer and professional markets.[11] Sony
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Minolta
Minolta
Minolta
Co., Ltd. (ミノルタ, Minoruta) was a Japanese manufacturer of cameras, camera accessories, photocopiers, fax machines, and laser printers. Minolta
Minolta
was founded in Osaka, Japan, in 1928 as Nichi-Doku Shashinki Shōten (日独写真機商店, meaning Japanese-German camera shop). It is perhaps best known for making the first integrated autofocus 35mm SLR camera system. In 1931, the company adopted its current name, an acronym for "Mechanism, Instruments, Optics, and Lenses by Tashima".[citation needed] In 1933, the brand name first appeared on a camera, a copy of the Plaubel Makina
Plaubel Makina
simply called "Minolta".[citation needed] In 2003, Minolta
Minolta
merged with Konica
Konica
Corporation to form Konica Minolta
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Smooth Trans Focus
The Smooth Trans Focus (STF) technology in photographic lenses uses an apodization filter to realize notably smooth bokeh with rounded out-of-focus highlights in both the foreground and background. This is accomplished by utilizing a concave neutral-gray tinted lens element next to the aperture blades as apodization filter, a technology originally invented (and patented) by Minolta
Minolta
in the 1980s, and first implemented in a commercially available lens in 1999
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Transmittance
Transmittance
Transmittance
of the surface of a material is its effectiveness in transmitting radiant energy
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Rodenstock Imagon
The Rodenstock Imagon is an achromat doublet photographic lens design uncorrected for spherical aberration used together with diffusion discs ("sink strainers") called sieve aperture (Siebblende (de) in German). The lens is one of the classic professional soft-focus "portrait lenses". In a joint effort with the pioneering photographer Heinrich Kühn, who, as a pictorialist, was artistically seeking for "romantic softness without sugariness, blurring without a woolly effect"[1] in images and had been experimenting with binocular lenses and soft filters and rasters in the 1920s already,[1] the lens was technically designed by Franz Staeble (de),[1][2] founder of the optical company Staeble-Werk (de) in Munich, Germany.[1] The resulting lens was marketed as Anachromat Kühn. Later in 1928,[1] the lens became the Tiefenbildner-Imagon, which was introduced by Rodenstock in 1930/1931 and produced up into the 1990s
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Exponentiation
Exponentiation
Exponentiation
is a mathematical operation, written as bn, involving two numbers, the base b and the exponent n. When n is a positive integer, exponentiation corresponds to repeated multiplication of the base: that is, bn is the product of multiplying n bases: b n = b × ⋯ × b ⏟ n . displaystyle b^ n =underbrace btimes cdots times b _ n . The exponent is usually shown as a superscript to the right of the base. In that case, bn is called "b raised to the n-th power", "b raised to the power of n", or "the n-th power of b". When n is a positive integer and b is not zero, b−n is naturally defined as 1/bn, preserving the property bn × bm = bn + m
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Geometric Sequence
In mathematics, a geometric progression, also known as a geometric sequence, is a sequence of numbers where each term after the first is found by multiplying the previous one by a fixed, non-zero number called the common ratio. For example, the sequence 2, 6, 18, 54, ... is a geometric progression with common ratio 3. Similarly 10, 5, 2.5, 1.25, ... is a geometric sequence with common ratio 1/2. Examples of a geometric sequence are powers rk of a fixed number r, such as 2k and 3k
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Integer
An integer (from the Latin
Latin
integer meaning "whole")[note 1] is a number that can be written without a fractional component. For example, 21, 4, 0, and −2048 are integers, while 9.75, ​5 1⁄2, and √2 are not. The set of integers consists of zero (0), the positive natural numbers (1, 2, 3, …), also called whole numbers or counting numbers,[1][2] and their additive inverses (the negative integers, i.e., −1, −2, −3, …). This is often denoted by a boldface Z ("Z") or blackboard bold Z displaystyle mathbb Z ( Unicode
Unicode
U+2124 ℤ) standing for the German word Zahlen ([ˈtsaːlən], "numbers").[3][4] Z is a subset of the set of all rational numbers Q, in turn a subset of the real numbers R. Like the natural numbers, Z is countably infinite. The integers form the smallest group and the smallest ring containing the natural numbers
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Ratio
In mathematics, a ratio is a relationship between two numbers indicating how many times the first number contains the second.[1] For example, if a bowl of fruit contains eight oranges and six lemons, then the ratio of oranges to lemons is eight to six (that is, 8:6, which is equivalent to the ratio 4:3). Similarly, the ratio of lemons to oranges is 6:8 (or 3:4) and the ratio of oranges to the total amount of fruit is 8:14 (or 4:7). The numbers in a ratio may be quantities of any kind, such as quantities of persons, objects, lengths, weights, etc. A ratio may be either a whole number or a fraction. A ratio may be written as "a to b" or a:b, or it may be expressed as a quotient of "a and b".[2] When the two quantities are measured with the same unit, as is often the case, their ratio is a dimensionless number
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Illuminance
In photometry, illuminance is the total luminous flux incident on a surface, per unit area. It is a measure of how much the incident light illuminates the surface, wavelength-weighted by the luminosity function to correlate with human brightness perception. Similarly, luminous emittance is the luminous flux per unit area emitted from a surface. Luminous emittance is also known as luminous exitance.[1]IlluminanceIn SI derived units
SI derived units
these are measured in lux (lx) or lumens per square metre (cd·sr·m−2). In the CGS system, the unit of illuminance is the phot, which is equal to 10000 lux
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