C
C-41: Development process used for almost all color negative film such as Fujicolor, Kodacolor, etc.
C-Band: The large satellite dishes often seen in rural areas are C-Band dishes.
Cantilever: In a phono cartridge, the arm that holds the stylus. See Phono Cartridge and Stylus.
CCD: Charge-Coupled Device. CCDs are used as sensors in digital cameras and video cameras. They consume much more power than CMOS sensors, but CCD technology has been in use for much longer and is less expensive to manufacture. They also require less computer processing power than CMOS sensors.
CD: Compact Disc, format developed jointly by Philips and Sony. CDs have a capacity of 700 MB and are used mostly for music and data storage, though video versions exist as well. See CD-i, CD-R, CD-RW, and VCD.
CD-i: CD-Interactive, an interactive multimedia compact disc format developed by Philips. It was not successful in the marketplace and removed from the market in 1998.
CD-R: Recordable CD. CD-R discs can only be written once.
CD-RW: Recordable CD which can be erased and re-written.
CED: Capacitance Electronic Disc. This consumer video format, also called “Selectavision” was created by RCA and featured video “records” similar to phonograph records that were played with a stylus, again like a phonograph record. To protect the fragile discs from damage they were stored in protective sleeves and extracted by the player mechanically for playback. Image quality was considered somewhat better than VHS but far behind Laserdisc or DVD. Selectavision was marketed from 1981 to 1984 and in that short time approximately 1700 different movie titles were produced.
Center-Weighted Meter: A light meter that measures all the light in a scene to determine exposure, but gives emphasis to light readings in the center of the frame. See Exposure, Light Meter.
CF: See Compact Flash.
Channel: A discrete source of information or a discrete pathway, usually used in describing audio components. For example, a 5-channel amplifier can drive 5 separate speakers with 5 different signals. The term is also used in digital photograph editing. For example, there are three separate channels for color: red, green, and blue and they can be adjusted independent of each other.
Chromatic Abberation: Chromatic aberration is caused by the inability of a lens to simultaneously focus all wavelengths of light at the same plane. Chromatic abberation often shows as purple fringing on the edges of subjects. See Apochromatic, Purple Fringing.
Clipping (amplifiers): Clipping occurs when an amplifier is driven past its limit. The amplifier cannot properly reproduce waveforms when overdrivven, and when looked at on a scope the tops of the waveforms are “clipped” off, hence the name clipping. Clipping can be very damaging to electronics and especially to speakers.
Clipped Highlights: A digital photography term used to describe images with burned-out whites having no detail.
CMOS: Complimentary-Metal-Oxide-Semiconductor, a type of image sensor used on digital cameras and camcorders. CMOS sensors are known to produce very smooth-looking images and they consume much less power than CCDs, leading to longer battery life and more shots per charge.
Coaxial Digital Audio: Digital audio connection using a standard RCA plug, usually colored orange.
Codec: Digital coding system used to record audio or video information. There are many codecs available for many different applications. For example, AAC, AVC, MP3, MPEG-2, and VC-1 are all examples of codecs. AAC and MP3 are audio codecs, AVC, MPEG-2 and VC-1 are video codecs.
Color Temperature: Measured in degrees Kelvin, color temperature refers to the color of light. Color temperature is important in both photographic and television applications. In photography, 3200 K corresponds to tungsten light and 5500 to daylight. Televisions have color temperature settings, usually listed as Cool, Medium, and Warm. The actual color temperature for each setting varies slightly by manufacturer. Warm is the most accurate setting and corresponds to approximately 6500 K. Medium is usually between 8,000 K to 10,000 K and Cool is 10,000 K and up. Using the Cool setting makes colors look brighter, but ithe Cool setting is not accurate and results in bluish flest tones. Most TVs use Cool as the default because the exaggerated colors make TVs stand out on the sales floor where they will be compared to other makes and models. For the most accurate picture the Warm setting should be used.
Coloration (sound quality): Coloration is changes in the timbre to the pure, original sound of a recording, “coloring” the sound and adding its imprint upon it . Colorations are usually attributed to playback components by subjectivisit audiophiles. See Timbre.
Colorstream: Term used by Toshiba to descrive component video inputs and outputs. It was first seen when DVD players were introduced to the market in the mid-1990s. See Component Video.
Comb Filter: In televisions, and Electronic filter that separates luminance and chrominance information in composite video signals. The quality of a comb filter can effect image quality. As TVs and connections transition to digital, the comb filter is of much less importance now. See Composite Video, S-Video.
Compact Flash: A type of memory card, abbreviated CF. Today they are used primarily in high-end digital SLRs as CF cards are inexpensive per GB, and pro-level digital SLRs create very large file sizes, requiring lots of storage space.
Component Video: Analog video connection using red, green and blue RCA connectors. It supports resolutions up to 1080i. Component video image quality is superior to RF, composite video and S-Video but inferior component video, DVI or HDMI. It is used on HDTVs lacking DVI or HDMI inputs. It is usually not possible to send a 1080i upscaled DVD image through component video as a digital DVI or HDMI connection is required. See Composite Video, Component Video, DVI and HDMI.
Composite Video: The highest quality analog video connection, used with HDTVs that do not ghasignal tinformation. It is superior to to RF, Composite Video, and S-Video, but inferior DVI or HDMI. Composite video cables and connections are yellow in color. See also Composite Video, DVI, HDMI, S-Video and RF.
Compression: Compression is a process that reduces size of digital files such as digital photographs and digital music files. There are two types of compression: Lossless, which preserves 100% of the quality of the original file, and lossy, in which some quality is lost. The amount of quality lost depends on the level of compression used. Under mild compression, the loss in quality may be minor or even imperceptible, with heavy compression the loss in quality will be very obvious, even to the untrained eye or ear. See also Lossy Compression and Lossless Compression.
Continuous Power: The amount of power an amplifier can produce indefinitely, on a continuous basis, without clipping. As per FTC regulations, continuous power ratings are provided in watts per channel into a given impedance with the level of distortion specified. See Watts and THD.
Converter Box: See DTV Converter Box.
Counterweight: Adjustable weight on the end of a tonearm. After a cartridge is installed, the counterweight is adjusted to balance perfectly, then tracking force is dialed in by moving the tonearm. See Phono Cartridge and Tracking Force.
Crossover: In a loudspeaker with two or more drivers, the crossover is an electrical circuit that divides incoming audio signals by frequency and sends the appropriate frequencies to each driver. For example, in a 2-way speaker, the crossover would send the appropriate frequencies to the woofer and the tweeter for reproduction. Subwoofers also have crossovers. See Crossover Frequency.
Crosssover Frequency: The frequency at which a crossover divides incoming signals. For example, in a two-way speaker with a crossover frequency of 2,000 Hz, frequencies under 2,000 Hz will be sent to the woofer and frequencies over 2,000 Hz will be sent to the tweeter. See Crossover.
CRT: Cathode Ray Tube. CRTs are the picture tubes used in tube-type televisions, projection televisions, and computer monitors.
Current (electrical): The flow of electrons in an electrical circuit. An analogy is the flow of water in a river. More current=more water.
