For many cameras, depth of field (DOF) is the distance between the nearest and the furthest objects that are in acceptably sharp focus in an image. The depth of field can be calculated based on focal length, distance to subject, the acceptable circle of confusion size, and aperture. A particular depth of field may be chosen for technical or artistic purposes. Limitations of depth of field can sometimes be overcome with various techniques/equipment.
Gunpowder, also known as black powder to distinguish it from modern smokeless powder, is the earliest known chemical explosive. It consists of a mixture of sulfur (S), charcoal (C), and potassium nitrate (saltpeter, KNO3). The sulfur and charcoal act as fuels while the saltpeter is an oxidizer. Because of its incendiary properties and the amount of heat and gas volume that it generates, gunpowder has been widely used as a propellant in firearms, artillery, rockets, and fireworks, and as a blasting powder in quarrying, mining, and road building.
A lens is a transmissive optical device that focuses or disperses a light beam by means of refraction. A simple lens consists of a single piece of transparent material, while a compound lens consists of several simple lenses (elements), usually arranged along a common axis. Lenses are made from materials such as glass or plastic, and are ground and polished or molded to a desired shape. A lens can focus light to form an image, unlike a prism, which refracts light without focusing. Devices that similarly focus or disperse waves and radiation other than visible light are also called lenses, such as microwave lenses, electron lenses, acoustic lenses, or explosive lenses.
Optics is the branch of physics that studies the behaviour and properties of light, including its interactions with matter and the construction of instruments that use or detect it. Optics usually describes the behaviour of visible, ultraviolet, and infrared light. Because light is an electromagnetic wave, other forms of electromagnetic radiation such as X-rays, microwaves, and radio waves exhibit similar properties.
Fireworks are a class of low explosive pyrotechnic devices used for aesthetic and entertainment purposes. The most common use of a firework is as part of a fireworks display, a display of the effects produced by firework devices.
The focal length of an optical system is a measure of how strongly the system converges or diverges light; it is the inverse of the system's optical power. A positive focal length indicates that a system converges light, while a negative focal lengh indicates that the system diverges light. A system with a shorter focal length bends the rays more sharply, bringing them to a focus in a shorter distance or diverging them more quickly. For the special case of a thin lens in air, a positive focal length is the distance over which initially collimated (parallel) rays are brought to a focus, or alternatively a negative focal length indicates how far in front of the lens a point source must be located to form a collimated beam. For more general optical systems, the focal length has no intuitive meaning; it is simply the inverse of the system's optical power.
Audio mixing is the process by which multiple sounds are combined into one or more channels. In the process, a source's volume level, frequency content, dynamics, and panoramic position are manipulated or enhanced. This practical, aesthetic, or otherwise creative treatment is done in order to produce a finished version that is appealing to listeners.
The f-number of an optical system is the ratio of the system's focal length to the diameter of the entrance pupil. It is a dimensionless number that is a quantitative measure of lens speed, and an important concept in photography. It is also known as the focal ratio, f-ratio, or f-stop. It is the reciprocal of the relative aperture. The f-number is commonly indicated using a hooked f with the format f/N, where N is the f-number.
The DirectDraw Surface container file format, is a Microsoft format for storing data compressed with the proprietary S3 Texture Compression (S3TC) algorithm, which can be decompressed in hardware by GPUs. This makes the format useful for storing graphical textures and cubic environment maps as a data file, both compressed and uncompressed. The file extension for this data format is '.dds'.
Reverse motion is a special effect in cinematography whereby the action that is filmed is shown backwards on screen. It can either be an in-camera effect or an effect produced with the use of an optical printer. There are various reasons why this technique may be adopted, such as for comedy effect or for safety reasons.
The 8 cm Granatwerfer 34 was the standard German infantry mortar throughout World War II. It was noted for its accuracy and rapid rate of fire.
Fleming Point is a rocky promontory in the U.S. state of California. It is situated in Albany, on the eastern shore of San Francisco Bay. Albany Bulb is an extension of the point, having been formed in the 1960s from construction debris.
Airbrush makeup is makeup sprayed onto the skin using an airbrush instead of being applied with sponges, brushes, fingers, or other methods. An airbrush is characterized by 3 major parts. A powered compressor is used to create an even and controllable airflow through a medical grade hose. The hose connects to a metal, trigger-actioned gun. An airbrush system can be altered to suit every type of makeup application by changing the air pressure for lighter, heavier, detailed or broader makeups. It is popular in film, theater, bridal makeup and sunless tanning. Systems designed for personal cosmetic use in the home are also available. Airbrush systems designed for home use are usually smaller and work at a lower pressures than systems used in industrial applications. The technique was first used in 1959 on actors in Ben Hur and has since grown in popularity in the entertainment business.
In sound recording and reproduction, audio mixing is the process of combining multitrack recordings into a final mono, stereo or surround sound product. In the process of combining the separate tracks, their relative levels are adjusted and balanced and various processes such as equalization and compression are commonly applied to individual tracks, groups of tracks, and the overall mix. In stereo and surround sound mixing, the placement of the tracks within the stereo field are adjusted and balanced. Audio mixing techniques and approaches vary widely and have a significant influence on the final product.
In pyrotechnics, a flame projector is a special effects device that projects a column of flame upwards, for a short, determined and controllable, period, usually on the order of a few seconds. The simplest form of flame projector is simply a vertical tube mounted on a base, containing powder and a hole for an electric match.
Fort Banks was a U.S. Coast Artillery fort located in Winthrop, Massachusetts. It served to defend Boston Harbor from enemy attack from the sea and was built in the 1890s during what is known as the Endicott period, a time in which the coast defenses of the United States were seriously expanded and upgraded with new technology. Today, the Fort Banks Mortar Battery is on the National Register of Historic Places.
Interruptible foldback (IFB), also known as interrupted foldback, interruptible feedback, or interrupt for broadcast is a monitoring and cueing system used in television, filmmaking, video production, and radio broadcast for one-way communication from the director or assistant director to on-air talent or a remote location. The names are a backfill for the Telex IFB-XXX model line. Less common names for the system include program cue interrupt (PCI) and switched talkback. IFB is often facilitated using an earpiece that on-air persons wear to get cues, feedback or direction from their control rooms. The earpiece itself may also be referred to as an IFB. Sometimes IFB is accomplished by the director talking to off-camera personnel who visually cue the on-camera talent.
The Ampulomet was an expedient anti-tank weapon which launched a 125 mm incendiary projectile made of spherical glass. This weapon was introduced in 1941 and used by the Red Army in World War II, but by 1942 was largely obsolete.
Thomas Glenn Robinson, better known as Glen Robinson, was an American special and visual effects artist, winner of six Academy Awards: two Academy Awards for Technical Achievement and four Special Achievement Academy Awards. As a special effects artist, his career spans over six decades from the mid-1930s to the mid-1980s, having worked literally on dozens of films.
