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In astrophysics and quantum physics a jiffy is, as defined by Edward R. Harrison, [13] the time it takes for light to travel one fermi, which is approximately the size of a nucleon. One fermi is 10−15 m, so a jiffy is about 3 × 10−24 s. It has also more informally been defined as "one light-foot", which is equal to approximately one ...
Exposure value is a base-2 logarithmic scale defined by (Ray 2000, 318): where. N is the f-number. t is the exposure time ("shutter speed") in seconds [2] EV 0 corresponds to an exposure time of 1 s and an aperture of f/1.0. If the EV is known, it can be used to select combinations of exposure time and f-number, as shown in Table 1.
The term "second" comes from "the second minute division of an hour", as it is 1 ⁄ 60 of a minute, or 1 ⁄ 60 of 1 ⁄ 60 of an hour. While usually sub-second units are represented with SI prefixes on the second (e.g. milliseconds ), this system can be extrapolated further, such that a "Third" would mean 1 ⁄ 60 of a second (16.7 ...
1 ⁄ 4 s, 1 ⁄ 2 s and 1 s: Also mainly used for motion blur effects and/or low-light photography, but only practical with a tripod-supported camera. [12] B (bulb) (fraction of second to several hours): Used with a mechanically fixed camera in astrophotography and for certain special effects. [13]
The second (symbol: s) is the unit of time in the International System of Units (SI), historically defined as 1⁄86400 of a day – this factor derived from the division of the day first into 24 hours, then to 60 minutes and finally to 60 seconds each (24 × 60 × 60 = 86400). The current and formal definition in the International System of ...
For example, 1/2.5 converts to 2/5 as a simple fraction, or 0.4 as a decimal number. This "inch" system gives a result approximately 1.5 times the length of the diagonal of the sensor. This "inch" system gives a result approximately 1.5 times the length of the diagonal of the sensor.
The light-second is a unit of length useful in astronomy, telecommunications and relativistic physics. It is defined as the distance that light travels in free space in one second, and is equal to exactly 299 792 458 m (approximately 983 571 055 ft or 186 282 mi). Just as the second forms the basis for other units of time, the light-second can ...
This film container denotes its speed as ISO 100/21°, including both arithmetic (100 ASA) and logarithmic (21 DIN) components. The second is often dropped, making (e.g.) "ISO 100" effectively equivalent to the older ASA speed. (As is common, the "100" in the film name alludes to its ISO rating.) Film speed is the measure of a photographic film ...