UHF – a band of radio frequencies often used to broadcast television signals. Mobile phones and satellite radio also use UHF signals. Any radio frequency between 300 MegaHertz (MHz) and 3,000 MHz (or 3 GigaHertz) is considered to be in  the UHF signal range. This range is less commonly known as the decimeter range. Frequencies immediately below 300 MHz are part of the VHF range. Radio frequencies above 3,000 MHz are categorized into the Super High Frequency and Extreme High Frequency ranges and together these two are considered the Microwave frequency range. UHF spectrum is used for an enormous variety of purposes, including: mobile phones, television broadcasters, GPS satellites and devices, satellite radio (XM and Sirius),
cordless phones, wireless networking, ham radio operators, and some RFID chips. Microwave ovens cause interference around 2450 MHz in the UHF band.

UPnP a/v – Universal Plug and Play audio and video. Is a set of standards for the seamless network connectivity and inter-operability between PCs, consumer electronics devices and mobile devices. One of the main characteristics of UPnP a/v devices is the easy set-up; e.g. via auto-detection of the media server. A UPnP a/v media-server is a software that enables network streaming of digital media such as photos, movies and music throughout the home. There are media servers available for most operating systems such as windows® (including vista) and mac. The most common ones are Windows® Media Connect® which is now part of Windows Media® Player 11, El Gato Eyeconnect or Allegro Media Server to support Itunes, Twonkymedia and many more.

USB – Universal Serial Bus. An interface that permits the “plug-and-play” connection to a computer of peripherals. This means that accessories can be plugged or unplugged from a computer while it is on. It is slower than FireWire, but faster than SCSI. Some of the latest capture devices, mostly external ones, are connected to the PC via the USB port. These offer a much lower data-rate than FireWire or i.LINK, but they do not require a capture card to be installed into the PC. Generally they are good for capturing high-resolution still images from video or lower resolution MPEG-1 video files.

UTP – Unshielded Twisted Pair cable.  Typically used for data transfer, contains multiple 2-conductor pairs twisted at regular intervals, employing no external shielding.

UV filter – a clear, neutral filter that absorbs Ultraviolet Radiation, with no effect on visible colors. The skylight filter is a UV filter with a pale rose tinge to it.

U-matic – a standard format for 3/4 inch videocassette recorders. This format has a maximum record or play time of one hour, and two discrete audio channels. That was introduced in 1969 from Sony. U-Matic was one of the first internally-enclosed formats, as opposed to more common open-reel tapes at the time. The tape width was 3/4″, and was fed in U-shape path about the helical head drum, giving the format the name. It is different from VHS or Betamax formats, which were developed much later.

ubiquitous computer – also known as “embodied virtuality”. Computers that are an integral, invisible part of people’s lives. In some ways the opposite of virtual reality, in which the user is absorbed into the computational world.

Ultimatte – trade name of a high-quality special effects system similar to a chromakey switcher. Electronic version of the blue screen technique used for motion picture special effects.

ultrasonic cleaner – device that transfers ultrasonic sound waves to a cleaning liquid or solvent that dislodges some embedded dirt.

ultraviolet radiation – radiation at the short wavelength end of the spectrum, not visible to the eye. It produces florescence in some materials, and is popularly known as “black light.” Invisible to the human eye, but can be seen by bees and butterflies. Most photographic films are sensitive to this electromagnetic radiation. Ultraviolet (UV) light falls in the range of the EM spectrum between visible light and X-rays. It has frequencies of about 8 × 1014 to 3 × 1016 cycles per second, or hertz (Hz), and wavelengths of about 380 nanometers (1.5 × 10−5 inches) to about 10 nm (4 × 10−7 inches). UV is generally divided into three sub-bands: UVA, or near UV (315–400 nm); UVB, or middle UV (280–315 nm); and UVC, or far UV (180–280 nm). Radiations with wavelengths from 10 nm to 180 nm are sometimes referred to as vacuum or extreme UV. These wavelengths are blocked by air, and they only propagate in a vacuum.

ultra-wide angle lens – an extra-wide angle lens. Generally refers to 35mm camera lenses with focal lengths shorter than 24 mm; a 17 mm lens is considered to be an ultra-wide angle lens.

umbrella – what the name implies, lighting accessory available in various sizes usually made of textured gold or silver fabric. Resembles a rain umbrella, used to soften illumination by bouncing or diffusing the light. Facilitates soft, shadowless illumination by reflecting light onto a scene.

unbalanced circuit – transmits the audio signal on a single conductor that is referenced to ground (grounded).

uncompressed audio format – an audio format in which every sample of sound is represented by a binary number. Examples are WAV or AIFF.

uncompressing – or decompressing. The act of expanding a compression file back into its original form. Software often comes in a compressed package.  Files can be uncompressed using popular tools such as PKZIP in the DOS operating system, WinZip in windows, and MacZip in MacIntosh.

undercranking – the process of slowing the frame rate of a camera down, so that when the captured pictures are played at the normal frame rate the action appears to be in fast motion. Historically, cameras were operated by turning a crank at a constant speed; hence “undercranking” refers to turning the crank too slowly. See also overcranking, frames per second, judder.

underexposure – a condition in which too little light reaches the film, producing a thin negative or a dark reversal or print. An image is underexposed when the film or image sensor receives too little light for proper exposure. Underexposure results in loss of detail in the subject’s dark areas, which can be almost completely black and featureless.

underscan – 1. reducing the height and width of the picture on a video monitor so that the edges, and thus portions of the blanking, can be observed.  2. Special video monitor that can reduce the size of the video image so the four outer frame edges can be viewed in their entirety.

undo – to revert back to the state that existed before a change was made. For example, when editing a digital image using software, the software allows you to undo or reverse an editing change.

unidirectional – highly selective microphone pickup pattern, rejects sound coming from behind while absorbing that from in front. See bidirectional, omnidirectional.

Unique Identifier  – UID, an identification marking, tag, database entry or file name which guarantees that the same identification is not used elsewhere. UID is immensely important in archives, libraries, or anywhere else where an item must be located unambiguously.

unipod – a “monopod,” a single-legged camera support that functions in a manner similar to a tripod.

unity gain – derived from the number 1, unity gain refers to no change in gain.

universal leader – a film projection leader, designed according to ANSI for the projection rate of 24 fps (1 1/2 feet per second), and recommended for use on all release prints.

unsharp mask – in digital image-editing software, this is a tool that permits you to incrementally increase sharpness in an image. It differs from the sharpen tool in that it allows you to control the degree of sharpening, helpful in avoiding over-doing it.

unsteadiness – an objectionable amount of motion in the screen image.

up-conversion – the process of converting low resolution video to higher resolution video.

upload – transfer files from a computer’s hard drive to another storage device, including an internet web site’s server.

upload the mind – the transfer of consciousness and mental structure of a person from a biological matrix to an electronic or informational matrix.

uprating – means “pushing” film, purposefully exposing film to less light than its iso indicates. To obtain images that are properly exposed from film that has been uprated or pushed requires over-development of the film.

uprezzing – upsampling. Resizing a digital image to a larger size.

upsample – enlarging a digital image by interpolation.

urban landscape – a photograph of a city taken in the manner of a landscape photograph, using buildings and other man-made features as graphical elements of composition that are treated in the same way the photographer would treat mountains and trees.

user bits – portions of VITC and LTC (time code), the scan lines in the vertical interval, above the active picture area, reserved for recording information of the user’s choosing, e.g., date, scene numbers, keykode numbers, time code, etc. A total of 32 bits are provided in time code which you can use to record such information as date, scene number, or reel number on videotape.

Utility Person – the person responsible for various manual tasks, running errands, or performing whatever jobs other members of their crew assign them.