Updated August 18, 2020
- AGC (Automatic Gain Control)
- Action Axis (180 degree rule)
- Ambient Sound (Ambience)
- Camera Control Unit (CCU)
- Chip Chart
- Chip Light
- Chroma Key
- Chroma Subsampling
- Close Up (CU)
- Color Bars
- Color Temperature
- Component Video
- Counter balance
- Crash Zoom
- CTL (Control Track)
- F-Stop Ramping (F Drop)
- Field of View (FoV)
- Focal Length
- FOH (Front of House)
- Follow Focus
- Foot Candle
- Frame Synchronizer
- Lens blower
- Lens brush
- Linear timecode (LTC)
- Long shot
- Loose Follow
- Lower Third
- Paint Box
- Pan Off
- Pan On
- Pedestal (Studio Pedestal)
- Pillar Box
- Point-of-view shot (POV)
- Prime lens
- Pull (Pull Out)
- Push (Push In)
- Safe Area (essential area, critical area, safe action area)
- Sampling Frequency
- Scripted Content
- SDI (Serial Digital Interface)
- Shot Sheet
- Siemen’s Star chart
- Speed Ramping
- Standard Definition
- Switcher ME (M/E, MLE)
- Tight Follow
- Tripod Lock
- Tripod Tension
- Truck (Truck Left, Truck Right)
- T number vs F stop
1.5 Gbit/s HD
A nominal bandwidth description of the Society of Motion Picture and Television Engineers (SMPTE) SMPTE 292 standard, also referred to as “HD-SDI” at 1920 (horizontal) x 1080 (vertical) resolution at either 23.98 & 24 (p or PsF), 29.97 & 30 (p or PsF), 59.94 & 60 (interlaced); as well as 1280 (horizontal) × 720 (vertical) at 60/59.94/50 frames progressive (p).
A description of the widescreen aspect ratio used for consumer TVs and professional video monitors. For every 16 units of measurement wide the image is 9 units of measurement tall, or described another way; the width is 1.78 times wider than the height. 16:9 is a common aspect ratio found in High Definition (HD), Ultra High Definition (UHD) and widescreen Standard Definition content.
3 Gbit/s HD
A nominal bandwidth description of the Society of Motion Picture and Television Engineers (SMPTE) SMPTE 372 & 424 standard, also referred to as “3G-SDI” at 1920 (horizontal) x 1080 (vertical) resolution at 50/60p.
4K (Ultra HD, UHD)
Ultra HD (UHD) typically refers to the ITU-R BT.2020 standard (aka: Rec. 2020). UHD is 3840 (horizontal) x 2160 (vertical) resolution video image at either 23.98, 24, 25, 29.97, 30, 50, 59.94, 60, 100, 119.88 & 120 frames per second frame rate progressive (p) in a 16:9 (1.78:1) aspect ratio.
4K (as opposed to UHD) is 4096 (horizontal) × 2160 (vertical), a 1.89:1 DCI Digital Cinema System Specification aspect ratio; therefore wider than UHD. Many people use the terms 4K, UHD, Ultra HD interchangeably, which can mean various video formats which have 2160 lines vertical.
A digital color reproduction standard where Y (luminance), U (color as defined graphically along a horizontal axis) and V (color as defined graphically along a vertical axis), are all sampled equally. 4:4:4 is a very high quality color sampling system typically used in green-screen ultimatte work.
A digital color reproduction standard where U (color as defined graphically along a horizontal axis) and V (color as defined graphically along a vertical axis) are both sampled at 1/2 the frequency of Y (luminance). As a result, changes in chrominance are recorded with half the fidelity as changes in luminance are. 4:2:2 is commonly used for “broadcast quality” capture.
A digital color reproduction standard where Y (luminance) is sampled for each pixel on each scan line, Cb (blue) is sampled every other time luminance is sampled, on every other line, Cr (red) is sampled every other time luminance is sampled on the third scan line, and so on.
In commercial live entertainment television, an “Act” is a continuous series of content elements called “Items” separated by commercial breaks. The content that occurs prior to the first commercial break would be part of Act #1.
Action Axis (180 degree rule)
An imaginary line drawn between two subjects or along a line of motion to insure the audience has continuity of screen direction. Crossing the action axis from one shot to the next creates an error in continuity perspective.
AGC (Automatic Gain Control)
(a) Circuitry used to automatically adjust an output signal regardless of varying input signal levels. (b) A circuit that applies either gain or loss to an input signal to maintain an output that is a constant average level over a typically 5 to 10 second averaging time. This emulates what an operator might do by manually riding the gain. Usable versions of AGC stop the level adjustment when the input drops below a threshold. This prevents boosting the background noise to full level when the program material stops. AGCs designed for sound reinforcement also have a means to limit the maximum amount of gain applied (say a 6 dB max gain limit) which reduces the chance that so much gain is applied the system goes into feedback.
(a) Undesirable video artifacts. Examples include: jaggies or stair-stepping (stepped or jagged edges of angled lines, especially at the slanted edges of letters), raster scan aliasing (e.g., twinkling or strobing effects on sharp horizontal lines), temporal aliasing (e.g., rotating wagon wheel spokes apparently reversing direction). (b) Digital audio artifacts generated when a signal that is higher in frequency than 1/2 the sampling rate enters a Analog to Digital converter (A/D). This is normally prevented by use of an anti-aliasing filter before the A/D. The higher the input frequency is above 1/2 the sampling rate the lower in frequency the artifacts. This is analogous to the backwards turning wheels sometimes seen in video. Aliasing therefore does not sound “natural” and sounds very different from normal signal distortion. Because aliasing sounds unnatural even small amounts can be audible.
Ambient Sound (Ambience)
The natural background audio of a given recording environment. On-camera dialog might be primary sound whereas traffic noise or a refrigerator hum or room tone would be ambience.
See Iris. For more information about aperture also see the article Understanding Iris, F stops, Aperture, Gain, Shutter, Depth of Field & Lighting.
A video source that is not gen-lockable. To gen-lock an asynchronous video signal a frame synchronizer, either internal to a production switcher, or external to a switcher must be used. Frame synchronizers incur delay (latency).
An adjustment near the mounting flange of a broadcast television lens which modifies the distance between the rear optical element of the lens and the camera’s imager. A zoom lens whose back focus is not correctly set will lose focus as the lens is zoomed in or out. For more information about back focus, see the article Understanding back-focus.
Bit (short for binary digit) is the smallest unit of data in a computer. A bit has a single binary value, either 0 or 1. Although computers usually provide instructions that can test and manipulate bits, they generally are designed to store data and execute instructions in bit multiples called bytes. In computer systems, there are eight bits in a byte.
1 Byte = 8 bits
1 Kilobyte = 1,024 Bytes = 8,192 bits
1 Megabyte = 1,024 Kilobytes = 1,048,576 Bytes = 8,388,608 bits
1 Gigabyte = 1,024 Megabytes = 1,048,576 Kilobytes = 8,388,608 Bytes = 67,108,864 bits
Black Burst (Bi-level sync)
Is an analog video signal used to reference and synchronize other analog or digital video signals. Synchronous video signals gen-locked together with a common black burst allow glitch-free switching in a production switcher.
Black Level (Pedestal Level)
The level of brightness at the darkest (black) part of a visual image. A black level adjusted too high will result in black appearing rather gray. A black level set too low (“crushed blacks”) will result in the loss of visible detail in the blacks.
When viewed on a Waveform monitor, an analog composite video a black level (in the United States, NTSC) is set to 7.5 IRE. Digital standard definition video (ITU-R Rec. 601) has a black level of 0 IRE (16 Y’, 8 bit). Digital High definition video (ITU-R Rec. 709) has a black level of 0 IRE (16 Y’, 8 bit and 64 Y’, 10 bit).
Breathe (Lens Breathing)
A subject captured within a frame appearing larger or smaller (shifting of angle of view) as the len’s focus adjustment is manipulated. A change in focal length (magnification) as focal distance (focus) changes.
Camera Control Unit (CCU)
A device used with multi-camera live production cameras to allow video & audio (camera microphone) out from the camera to be sent to a control room; and gen-lock, tally, headset communications, iris control, paint control, return video and prompter signals, and camera power to be sent from a control room back to the camera head. The cable connecting the camera head to the CCU is typical SMPTE or TAC fiber, Triax or Multicore.
A unit of luminescence or light intensity. A common wax candle emits light with a luminous intensity of roughly one candela.
A chart used for reference purposes while white balancing cameras, illuminated by talent’s key light, or a portable chip light.
A portable light, the same color temperature as the stage’s key lights, which is moved around to each camera to illuminate a Chip Chart while white balancing the cameras.
The color component of a video signal.
A color-based video matte (an overlay) which allows through the background layer image where a selected color, typically green or blue, on a foreground image is replaced with the corresponding areas of a background image.
The practice of encoding images by implementing less resolution for chroma information than for luma information. It is used in many video encoding schemes — both analog and digital — and also in JPEG encoding
A type of lens mount commonly found on 16mm movie cameras, closed-circuit security cameras, microscope phototubes and some POV production cameras. C-mount is an alternate mounting system to B4 (found on most broadcast lens), PL (found on cinematography lenses) and various DSLR mount.
A standardized video signal which can be transmitted, recorded or played back, and is used to evaluate the accuracy of a source video signal, or a signal’s path, in regard to luminance (how bright the image is), chrominance (how saturated/desaturated colors are), phase (the hue of a color), and black levels (to what extent details may be seen in blacks). The top 2/3rds of SMPTE color bars contain seven vertical bars (white, yellow, cyan, green, magenta, red and blue) each at 75% intensity. These colors represent the three base colors – green, red, and blue; and three derivative colors – yellow, magenta and cyan; and white (which is green, red and blue at equal maximum amplitudes). The order the bars appear when viewed as SMPTE color bars creates a stair-step appearance when viewed on a waveform monitor in “luminance mode.”
The bottom section of the SMPTE color bars includes a white square at 100% intensity and a rectangle of black at 7.5% intensity. Some SMPTE color bars include a “pluge” (three small vertical bars) at the bottom right of the screen. The furthest right of the three small vertical bars is black at a level of 11.5 IRE. The middle small vertical bar is at 7.5 IRE and the leftmost small vertical bar is at 3.5 IRE. When adjusting display devices (such as video monitors or projectors), the rightmost pluge bar (11.5 IRE) should be visible barely as a dark grey, while the left two pluge bars should be completely black. When adjusting video signals on a waveform monitor, the 7.5 IRE pluge black bar should align with the 7.5 IRE line on the waveform display.
The bottom left hand side of the SMPTE color bars may have a “I” and “Q” rectangular “blackish” boxes. One of these is a very dark blue hue while the other is a very dark purple. When viewed on a vectorscope, I and Q appear as two short lines, ninety degrees apart from each other appearing at 147 degrees and 237 degrees on the vectorscope scale.
In practical terms, a measurement in degrees (Kelvin) describing the color of white light (actually, the temperature or reflected heat of a black-body radiator, radiating reflected light of a color similar to the light source). Very warm color temperatures (1800 K) are typically emitted by candle light, or during a sunrise or sunset. Warm color temperatures (2700-3200 K) are typically emitted by incandescent lighting instruments. Cool color temperatures (5000 K) is typically emitted by a midday sun whereas an overcast sky would typically be cooler (6500 K). CRT and LCD screens are typically somewhere between 6500-9500 K.
A video system where the color and luma components of the signal are kept separate (as YUV, RGB, YPbPr, Y (B-Y) (R-Y)) to maintain higher image quality.
Human color perception. The adjustment of red and blue gains (or red, green and blue gains) and/or red and blue pedestal (blacks) to achieve a given esthetic or to match live cameras.
The combination of several images into one image; or, an (analog) video system where the color (chroma) and brightness (luma) portions of a image are combined into one signal.
Referring to the frame of the image and how all the elements of the scene appear within it. Shot composition refers equally to the camera’s field of view, as it does to discernment regarding where the point of interest should be positioned in the frame and what objects, foreground and background should be included or excluded from the frame.
A system within a camera’s pan/tilt tripod head applying opposing force when the camera operator tilts the camera. Counter balance is typically used to assist the camera operator in maintaining a level (to the horizon) pitch, or a desired pitch angle above/below horizontal.
Depth of Field (DoF)
The distance within a frame, closer to the camera, or farther from the camera, that remains in-focus. A narrow or shallow depth of field typically has the subject (or part of the subject) in-focus; with the foreground and background out of focus, thus drawing the viewers attention to the in-focus portion of the screen. A deep depth of field will have the subject as well as the foreground and background in-focus, thus allowing the viewer to explore the frame and look where they will. For more information about depth of field, see the article Understanding Iris, F stops, Aperture, Gain, Shutter, Depth of Field & Lighting.
A camera’s detail circuit controls the sharpness of an image. Too much detail will result in a image looking unflattering. Too little detail will result in the image looking soft, almost out of focus. Some cameras have various different types of detail controls, including the ability to adjust “skin detail” separately from overall detail.
Dolly (Dolly In, Dolly Out)
(a) A device with wheels which supports the camera. (b) The act of physically moving the camera closer or further to/from the subject in a frame thereby increasing/decreasing the field of view with a static focal length.
Dolly Zoom (Zolly)
Combining a dolly shot (the act of physically moving the camera closer or further to/from the subject in a frame thereby increasing/decreasing the field of view) with a zoom, changing a lens’ focal length from a wider focal length to telephoto, or vice versa. Dolly Zoom or Zolly shots often calibrate and coordinate the changes in camera distance and speed with focal length and speed, maintaining static framing while the angular field of view is changing. See the video below for a good example:
A copy, or to make a copy.
A canned air product manufactured by Falcon, used to remove dust or dirt from electronics. For instructions on lens cleaning see this post.
An opening image of a sequence of images, program or a scene. Typically a wide shot, extreme wide shot or distant perspective that orients viewers to the overall setting and surroundings.
Field of View (FoV)
The observable area a camera operator allows into a videographic frame for the audience to see. The vertical and horizontal angles – in degrees – which a lens captures light combined with a given distance, camera to subject. Examples are below or see the article, Shot Composition.
Extreme Closeup Shot (Abbreviated “ECU” or “XCU”): A camera frame tighter or closer-in than a Closeup shot.
Medium Closeup Shot (Abbreviated “MCU”): A camera frame in which the vertical space captured is approximately eighteen inches (1’6″) vertical. In the context of a presenter’s presentation, also known as a Bust shot.
Medium Shot (Abbreviated “MED”): A camera frame in which the vertical space captured is approximately thirty inches (2’6″) vertical. In the context of a presenter’s presentation, also known as a Waist shot.
Medium Wide shot (Abbreviated “MWS”): A camera frame in which the vertical space captured is approximately four foot six inches (54″) vertical. In the context of a presenter’s presentation, also known as a Head to Knees shot.
Wide Shot (Abbreviated “WS”): A camera frame in which the vertical space captured is approximately six foot six inches (78″) vertical, or equivalent to capturing a human male or female completely, from the top of their head to their toes, regardless of the subject’s height. In the context of a presenter’s presentation, also known as a Head to Toe shot.
F Stop Ramping (F Drop)
A phenomenon found in zoom lenses whereby the lens becomes less light efficient when zooming in. To avoid F stop ramping (F Drop) altogether, the “entrance pupil” of the focusing lens group must be equal to or greater in size than the lens’ telephoto focal length divided by the F-stop number. However this would result in lenses becoming much larger and heavier, and so a compromise is made resulting in handheld capable lenses being less light efficient as the lens’ focal length increases.
In reference to a video signal, a field is a set of lines either produced or scanned by one sweep down the screen. For interlaced video, it takes two such fields to make one frame (complete image).
A partially transparent material that passes, blocks or manipulates light; or, an electronic circuit or unit that passes or blocks signals of a particular type or frequency; or, any circuit or device (hardware or software) that shapes or conditions a signal or information.
Apple Computer’s trademarked name for an IEEE1394 signal or connection.
Within a lens, focal length is the distance between the point of convergence (typically at the rear of the lens) to the sensor or film within your camera, represented in millimeters. A lens’ focal length tells us the angle of view, how much of the scene will be captured. The longer the focal length (the higher the number), the narrower the angle of view and therefore the higher the magnification. The shorter the focal length, (the lower the number) the wider the angle of view and the lower the magnification.
FOH (Front of House)
The part of a venue or church that is open to the attendees, in the room where the performance or event will take place; typically where some of the technical-facilities control equipment (the PA system’s audio mixing desk, the stage lighting control console) and their operators are seated during the show.
The controlling of a lens’ focus so that an image maintains sharpness and clarity despite camera or the subjects movement. Or, an accessory device used by cinematographers to operate a lens’ focus barrel, controlled by either the camera’s operator or the First Assistant Cameraman, as in “Studio Follow Focus.” Studio Follow Focus devices often have discs which the camera operator or First AC can mark focal distance cues, or “witness marks.”
A unit of illuminance or light intensity. A foot-candle is the illuminance cast on a surface by a one-lumen source one foot away.
(a) To compose a shot in video or film, to make the image fit into the “frame” of the screen; (b) a spatially complete video image, at one given temporal point in time.
A digital buffer that stores a frame of video, compares the sync information to a reference, and releases the frame at a specific time to adjusting for timing errors. Frame synchronizers are typically used when integrating non-genlockable sources into a video production switcher.
The act of composing a shot, selecting the Field of View for the desired content and angle. The judicious act of determining which content to omit.
In reference to camera gain, the amount of amplification the camera is currently applying to the imager’s output, expressed in decibels. For more information on gain, see the article Understanding Iris, F stops, Aperture, Gain, Shutter, Depth of Field & Lighting.
Nonlinear luminance values in video or still image systems.
The technique of adjusting the picture timing (synchronization) of a video source signal (a camera, VTR, character generator, etc.) to conform with a video production switcher, or a master sync generator in a video production system.
GPI (General Purpose Interface)
A basic trigger between one electronic device and another.
(a) The amount of space between the top of a subject’s head and the upper edge of the screen. The amount of headroom typically sought is commensurate to the tightness of the frame or Field of View. Tighter frames receive less headroom. Wider frames are given more headroom. (b) The audio difference in peak level between the signal peak and the peak level the system can handle without distortion. Headroom is required to allow for the fact that sounds can vary a lot and max levels can be hard to predict. For example when setting levels during a rehearsal it is wise to leave a lot of headroom to allow for levels to be higher during the performance.
For more on shot composition, see the following article.
High Definition (HD)
Typically refers to the SMPTE 292 standard, a 1920 (horizontal) x 1080 (vertical) resolution video image at either 23.98 & 24 (p or PsF), 29.97 & 30 (p or PsF), 59.94 & 60 frames per second (interlaced); as well as 1280 (horizontal) × 720 (vertical) at 60/59.94/50 frames per second progressive (p).
HDR (High Dynamic Range)
In reference to video production, High Dynamic Range (HDR) video is a subset of HD (High Definition) or UHD (Ultra High Definition) which allows a greater contrast range (i.e.: a greater “dynamic range”) than previous HD broadcast standards would allow. For the consumer, a HDR signal viewed on a HDR television will allow brighter brights with more detail in those brights (without getting blown out); and darker darks, with the ability to see into the shadows – than a non-HDR HD or UHD program would allow. Similarly Wide Color Gamut (WCG) allows a greater color pallet than previous HD broadcast standards would allow. Unlike digital still photography, HDR in video production does not involve the merging of two exposures to create one composited image.
Currently there are multiple competing HDR encoding formats which are not necessarily compatible with each other. They include HDR10 (a 10 bit, 1,000 nit, static metadata open source standard supported by Samsung, Sony and Microsoft), HDR10+ (a dynamic metadata standard supported by Samsung, Panasonic, Philips, Amazon and 20th Century Fox), Dolby Vision (a proprietary hardware based, dynamic metadata, 12 bit, 10,000 nit capable system), HLG (developed by the BBC and NHK Japan to be a backwards compatible system for viewers without HDR capability), and Advanced HDR (a new cross-compatible-HDR format).
One of the three attributes of color. A specified tint, saturation and brightness.
Hyperfocal distance: the distance between a camera lens and the closest object that is in focus when the lens is focused at infinity.
A digital interface capable of transporting data at up to 400 Mbps. Also referred to as Firewire.
A switch often found on professional video tape recorders/players allowing an operator to select whether or not the VTR is referenced to external signals (as in black burst) or an internal signal. When being used as a recorder, the Internal/External sync switch would often be set to Internal, whereas then used as a player, the Internal/External sync switch would often be set to External.
A production technique which utilizes one or more video cameras capturing a live speech or performance in front of a live audience and simultaneously video projecting those camera(s) onto screen(s) with the intent of aiding the audience (in the venue) seeing the presenter or performer better/larger than they could with the naked eye.
Resistance in an electrical circuit, measured in Ohms. Impedances must be matched in audio circuits to avoid distortion and the introduction of noise.
A ring on a lens which controls aperture, typically expressed in F-stop numbers. The lower the f-stop number the wider the aperture, allowing in more light. The higher the f-stop number the smaller the aperture, allowing in less light. Wide aperture (smaller f-stop numbers) reduces the depth of field. Smaller aperture (higher f-stop numbers) increases or deepens the depth of field. For more information regarding iris, see the article, Understanding Iris, F stops, Aperture, Gain, Shutter, Depth of Field & Lighting.
A video recording only of a specific camera, or video element, as opposed to a linecut.
In live entertainment television an Item is a section of dialog, or a song, a playback element, etc., contained within a Act.
ITU-R Rec. 709
Also known by the abbreviations Rec. 709, BT.709, and ITU709, this 1990 adopted specification standardizes high-definition broadcast television. Rec. 709 refers to HDTV systems having roughly two million luma samples per frame and defining an R G B or Y CB CR encoding system with either 8 or 10 bits per sample in each color channel. Color rendition specified by Rec. 709 reproduces only a portion of that which is otherwise visible.
A brand name which manufactures camera support device where the camera is placed on one end of a long arm, the operator (and counter balance weights) are on the opposite end of the arm and a fulcrum is in the center. A competing similar system is manufactured by CamMate. Typical Jimmy Jib shots are high/low angle, or sweeping motion shots where the camera moves in an arc.
(a) In lighting, short for “key light,” the principle (usually brightest) light used to illuminate the main subject; (b) a video image whose color or brightness is used to determine the transparency of parts of a foreground image, typically used to superimpose one image over another with a video production switcher. See chroma key.
(a) An amount of time, typically measured in milliseconds or video frames, which a device requires to process, convert or synchronize a video signal. Latency of a video signal only will cause audio to appear out of lip-sync. Video latency is especially problematic in production environments projecting cameras (Imag) as delaying audio (through a PA system) of a presenter/teacher/preacher to match the latent video is not an acceptable solution. The average attendee will begin to notice latency/lip-sync mismatch at about 4-6 frames of delay. (b) All digital audio adds some latency to the audio, but typically less than the latency involved with video processing. The distance from the loudspeaker to the listener will also add roughly one millisecond of latency for every foot of distance.
A bellows device, typically made out of rubber, used to remove dust or dirt from a lens. See the Giottos AA1900 Rocket Air Blaster. For instructions on lens cleaning read this post.
A soft bristle device used to remove dust or dirt from a lens. See the LensPen NLP-1. For instructions on lens cleaning read this post.
The practice of transferring widescreen content to a video aspect ratio while preserving the original content’s horizontal field of view. For example, on video displays with a 4:3 aspect ratio, the resulting image will have mattes (black bars) above and below the content. LTBX is the identifying acronym for films and images so formatted.
A video recording of a production switcher’s Program output. Linecut’s which are “dirty” include all graphical elements. Linecut’s which are “clean” refer to Program without lower-third graphics, logos, bugs, etc.
A camera shot, centered and perpendicular to the primary talent’s shoulder line, at a wider field of view than a “tight follow” shot. See the article, Camera Locations.
A camera’s view of a subject or scene from a distance, showing a broad perspective. See Extreme Wide Shot. Also can describe the likelihood a presenter will get you his/her graphics in a timely manner.
In video production, a “lower third” is a graphic superimposed over static, pre-recorded or live motion video, placed in the lower area of the screen (thus the name); though not necessarily the entire lower third portion or any specific location other than somewhere on the bottom 1/3rd of the screen. A lower third can simply be text overlying video, or may contain text drop shadows, stroke (an outline around the text), graphical elements such as boxes, line art, complex images, graduated shading in a static or animated form.
High quality lower thirds are keyed over video utilizing an alpha channel (sometimes referred to as a HICON , for “high contrast”) to determine what parts of the graphic or text layer should be transparent – allowing the background video through – versus what part of the graphic appears visible on top of background layers.
LTO – short for Linear Tape Open, a technology that was developed jointly by HP, IBM and Certance (Seagate) to provide a clear and viable choice in an increasingly complex array of tape storage options. LTO technology is an “open format” technology, which means that users will have multiple sources of product and media, and the open nature of LTO technology also provides a means of enabling compatibility between different vendors’ offerings.
A measurement of the total quantity of visible light emitted by a source. The difference between lumens and lux is that lux takes into account the area over which the light is spread. For example, 1000 lumens concentrated into an area of one square meter lights up that square meter with an illuminance of 1000 lux. However the same 1000 lumens spread out over ten square meters would produce a dimmer illuminance of only 100 lux.
The brightness or intensity of an image, in particular the brightness without regard to color.
(Abbreviated “lx”) a measurement of light’s intensity. One lumen per square meter.
(Audio) The difference between the level shown on the meter and the actual peak level of the signal. Some audio level meters, particularly those marked in Volume Units (VU) attempt to display an average of the level over a short time. This is done because it correlates well with the perceived level. However, all signal types have peak levels that are higher than such a meter displays. Some sorts of signals such as flute will have peak levels only a few dB higher than shown in VU. Other sorts of signals such as piano, and percussion, can have peak levels 30 dB or more higher than shown in VU. Please note this meter lag is not the same as Headroom, and must be accounted for in addition to headroom.
A highly sensitivity audio input intended for very low level signals, such as a microphone, typically below –30dBu.
A moiré pattern occurs when an object that being shot contains repetitive patterns of detail (such as parallel lines, or dots, etc.) which may exceed a camera’s imager resolution. Moiré is identified as strange-looking wavy pattern imposed over the repetitive detail area of a frame. Changing a camera’s angle to the subject; or a camera’s field of view (either by adjusting the distance to the subject at a given focal length, or by adjusting focal length at a given distance) will mitigate moiré. Additionally, changing a camera’s aperture by stopping down to very narrow F-stops (f/11, f/16, or greater, etc.) will cause an optical phenomenon known as “diffraction,” which also may mitigate moiré.
A poorly planned or executed line-cut shot selection where the primary point of visual interest on a subsequent shot is dissolved (or cut) over the primary point of visual interest, located in the same area of a frame, from a preceding shot. Morphing is considered acceptable when occurring between tight follow and loose follow primary cameras. Morphing is not considered acceptable for angled-off or secondary camera shots.
Production content which tells a story, typically fictional or fictionalized, regarding an event or narrative.
NDI (Network Device Interface)
Developed by NewTek, NDI is a professional “IP Video” protocol which is royalty-free licensed for Windows, Linux and macOS, iOS, Android, Raspberry Pi and FPGA platform devices. Unlike the Society of Motion Picture & Television Engineers SMPTE 2110, SMPTE 2022-6 and Adaptive Sample Picture Encapsulation (ASPEN) which require 10 Gigabit networks, NDI is designed to run over Gigabit networks allowing adoption of the protocol using existing computer networking infrastructures, achieved through the use of video data compression using the NDI codec which delivers 1080 full HD video at VBR (Variable Bit Rate) data rates typically around 100 Mbit/s. NDI carries video, multichannel uncompressed audio and metadata. Metadata messages can be sent in both directions allowing the sender and receiver to message one another over the connection with arbitrary metadata in XML form. Directional metadata allows for functionality such as active tally information fed back to sources. NDI also allows senders to determine the number of connected receivers, so they can skip unnecessary processing and network bandwidth utilisation when there are no NDI receiver clients connected.
Neutral Density (ND) Filter
An optical filter placed either in front of a lens, or internal to the camera, to reduce the amount of light hitting the camera’s imager, without adjusting the camera’s shutter, aperture or gain. A “ND 0.3” filter will reduce light by one stop (or phrased another way, it will reduce the light by half). A “ND 0.6” will reduce light by two stops. “ND 0.9” is three stops.
A unit of luminance equivalent to one candela per square meter.
The distance between the subject and the edge of the frame ,in the direction the subject is looking. The more profile a camera angle is, the more Nose room is given. The more dead-on a camera angle is, the less Nose room is give. Also called “Look room.”
National Television System Committee is the analog television system that was used in the United States, Canada, Japan, Mexico, the Philippines, South Korea, Taiwan and some other countries. The vertical resolution of NTSC was 525 lines.
A framing technique where the primary subject is in the background while the back of a second person’s shoulder and head are in the foreground of a shot. Often used in interview situations.
Phase Alternating Line was the analog television system used for broadcast television in large parts of the world outside the United States. Vertical resolution of PAL was 625 lines.
Pivoting a camera horizontally, right to left, or left to right. A shot in which the camera’s field of view moves horizontally around a fixed axis point.
Pan Off (Pan Off Left/Right)
A camera direction term where the camera frame begins with the subject in the frame and the camera operator panning until the subject is no longer visible.
Pan On (Pan On Left/Right)
A camera direction term where the camera frame begins without the subject in the frame and the camera operator panning until the subject is revealed and positioned where desired.
A parfocal lens is a zoom lens which remains in sharp focus (without adjustment to the focus barell) even as the focal length (magnification) changes. The following statement assumes the lens to subject distance has not changed simultaneously as well. Varifocal lenses on the other hand are those which the focus changes when focal length changes.
Pedestal (Studio Pedestal)
A camera move where the entire camera body & lens raises or lowers vertically. Also the name of a camera support device used to dolly, truck, crab and perform vertical camera movements, as in “Studio Pedestal.”
Black bars (mattes or masking) placed on the sides of the content image. Pillar boxing is sometimes necessary when film or video that was not originally designed for widescreen displays is shown on such, or narrower widescreen content is displayed within a wider aspect ratio, such as a 1.85:1 content on a 2.35:1 projection screen.
A picture element, the smallest part of a picture that can be addressed or changed in a digital image. Pixels are normally arranged in a regular 2-dimensional grid, and are often represented using squares or rectangles.
Point-of-view shot (POV)
A camera framing perspective whereby the camera assumes a subject’s view and thus the audience see what the subject would have seen.
A lens designed to work at only one focal length. Often used due to superior image quality compared to zoom lenses.
Progressive (or non-interlaced) scanning is a method for displaying, storing or transmitting moving images in which all the lines of each frame are drawn in sequence. This is in contrast to the interlaced scanning used in traditional television systems where only the odd lines, then the even lines of each frame (each portion of the image, now called “a field”) are drawn alternatively.
Progressive segmented Frame is a High Definition mastering video format designed to acquire, store, modify and distribute progressive content using interlaced equipment and media.
Pull (Pull Out)
The act of physically moving the camera further from the subject in a frame thereby increasing the field of view with a static focal length. Typically done when the camera is on a dolly or a pedestal. (2) the term “pull out” may also be used to describe a simple zoom move, where the camera physically remains at a static distance to the subject and the camera operator slowly changes a zoom lens’ field of view by decreasing the lens’ focal length. (3) when using a film camera, the term “pull” may refer to the technique of telling, or setting a camera’s ISO dial lower than the actual ISO rating of the film one is using, thereby overexposing captured images. Pulling during film acquisition may be done to achieve a lower shutter speed (achieving a given motion esthetic). (4) During the development process of camera film, “pulling” may refer to leaving the film in the developing-chemicals shorter, thereby achieving a shallower contrast range when using overexposed film.
Push (Push In)
The act of physically moving the camera closer to the subject in a frame thereby decreasing the field of view with a static focal length. Typically done when the camera is on a dolly or a pedestal. (2) the term “push in” may also be used to describe a simple zoom move, where the camera physically remains at a static distance to the subject and the camera operator slowly changes a zoom lens’ field of view by increasing the lens’ focal length. (3) when using a film camera, the term “push” may refer to the technique of telling, or setting a camera’s ISO dial higher than the actual ISO rating of the film one is using, thereby underexposing captured images. Pushing during film acquisition may be done to achieve a higher shutter speed (achieving a given motion esthetic). (4) During the development process of camera film, “pushing” may refer to leaving the film in the developing-chemicals longer, thereby achieving an unequal contrast range when developing underexposed film (the highlights and brights become brighter, while the darks remain without detail in the shadows).
Shifting focus between subjects in the frame. Often used to shift optical focus between foreground and background elements, so a viewer’s attention is directed intentionally from one subject to another subject within the frame as the focus shifts.
The horizontal lines (scan lines) displayed on a TV or computer monitor. This is the origin of the term “raster graphics,” which is the major category that all bitmapped images and video frames fall into (GIF, JPEG, MPEG, etc.)
Rec. 601 (BT. 601)
or its former name, CCIR 601, is a standard published by the CCIR (now ITU-R) for encoding interlaced analogue video signals in digital form. It includes methods of encoding 525 line 60 Hz and 625-line 50 Hz signals, both with 720 luminance samples and 360 chrominance samples per line. The color encoding system is known as YUV 4:2:2, that being the ratio of Y:Cb:Cr samples (luminance data:blue chroma data:red chroma data).
A shoot performed outside of a controlled studio environment, on location. Also called (in Europe) an “Outside Broadcast” or “OB.”
Remote Control Panel (RCP)
The controller which allows a Video Engineer (“Shader”) to adjust a camera’s iris, pedestal, detail and colorimetry. If connect to a camera’s CCU, the device is typically called a “RCP.” If manufactured to connect directly to the camera’s head, then typically called a “Paint Box.”
A feature typically found on video production cameras with CCUs (camera control units) whereby the camera operator can view alternative content in the camera’s viewfinder, such as the line-cut, or a preview of the placement of a digital video effects box to be superimposed onto the image.
One format of component video; one of the descriptions of component color space, in this case Red, Green, Blue. See also Y.U.V..
Rule of Thirds
A composition theory based on dividing the screen into thirds vertically and horizontally and placing the main subject along those lines. Example:
Safe Area (essential area, critical area, safe action area): Image boundaries within which contents of a television picture are sure to be seen regardless of the viewer’s television receiver aspect ratio, sizing or cropping. A safe area encompasses (approximately) the inner 80 percent of the image as is typically used to determine where important graphics or content should be placed.
For more information, see the article titled, “Shot Composition.”
The number of times per second that a sound’s waveform is captured and converted to digital form, expressed as kiloHertz (kHz.).
Indicates the strength or richness of a color; from paint mixing terminology, the amount of the color pigment in the mixture.
In feature films, a sequence of related shots usually constituting the action in one particular location [See “Shot“].
Production genres where all dialog is predetermined, rehearsed and delivered as previously planned. Scripted content is often “blocked,” meaning the physical location of each camera and talent delivering lines is planned out and rehearsed. Examples of scripted content include narrative feature films, commercials, etc.
SDI (Serial Digital Interface)
A family of digital video interfaces standardized by SMPTE (The Society of Motion Picture and Television Engineers). SMPTE 259M-C is a 270 Mbit/s bitrate, 4:3 or 16:9 aspect ratio, 525 total vertical lines, 720 x 486 active lines at 59.94i frame rate standard often referred to as SD-SDI. SMPTE 292 is a 1.5 Gbit/s bitrate, 16:9 aspect ratio, 1920 x 1080 lines at 59.94i, 29.97p, and 23.98p frame rate often referred to as HD-SDI.
ITU-R BT.656 and SMPTE 259M define digital video interfaces used for broadcast-grade video. A related standard, known as high-definition serial digital interface (HD-SDI), is standardized in SMPTE 292M; this provides a nominal data rate of 1.485 Gbit/s
See Video Operator.
The intentional composition or framing of a scene.
A list of shots specific to a given camera, which includes who the camera operator is to frame, the field of view, as well as any specified motion the camera is required to give. Shot numbers refer to a sequential list of shots, most often cued by a live television Associate Director (AD). Shot sheets come in both paper and electronic forms.
With video cameras, shutter is a device which controls the motion esthetic achieved. Slow shutter speeds (or turning the shutter off) may give the impression of motion being blurred. High shutter speeds lend themselves to a motion esthetic which is temporally fast-paced, in some cases to the point of appearing visually staccato. Lower shutter speeds (or turning the shutter off) allow more light to reach the camera’s imager. Higher shutter speeds reduce the amount of light and therefore affects exposure. For more information on shutter, see the article Understanding Iris, F stops, Aperture, Gain, Shutter, Depth of Field & Lighting.
Siemen’s Star chart
A chart used to aid in adjusting a len’s back-focus.
A slow motion (over-cranking) or fast motion (under-cranking) visual effect where the images go from normal speed to slow motion, or normal speed to fast motion, or either vice versa within a shot. Slow motion (over-cranking) is achieved by shooting more frames per second than the display system will reproduce (i.e.: shooting 60 frames per second and displaying 24 fps will result in a 2.5x slow motion effect, each second of frames captured will have 2.5 seconds duration when viewed. Fast motion (under-cranking) is achieved by shooting fewer frames per second than the display system will reproduce (i.e.: shooting 12 frames per second and displaying 24 fps will result in a 2x speed-up motion effect, each second of frames shot will have one-half of a second duration when viewed. Speed Ramping is the gradual changing from one frame rate per second to another frame rate per second.
ST-2210 IP is a multiplex standard where video, audio and ancillary data signals are parts of different streams, therefore separately route-able. Image sizes are arbitrary, up to 32,000 x 32,000, uncompressed and Y’Cb’Cr, RGB, or I’Ct’Cp at 4:2:2 10 & 12 bit, or 4:4:4 16 bit and more. HDR (PQ & HLG) is supported. Audio is compliant to AES67 (48kHz, 16 & 24 bit depth), and AES3.
Standard Definition (SD or SDTV)
Standard Definition (SD or SDTV): In the United States, a 480 vertical line television system based on NTSC (National Television System Committee) standards.
A brand name which manufactures body-worn camera stabilization devices. Steadicam shots are typically a hybrid of that which a dolly or a handheld camera operator might achieve.
In regard to the framing of objects, the subject is the primary point of interest within a frame. The placement of our subject, the inclusion or exclusion of foreground and background elements, and lighting are chosen intentionally to communicate to the viewer relationship, stature, and perspective.
Standard definition video, separated into “Y” (luminance, brightness) and “C” (chroma, color), S-Video (or Y/C) uses a specific round 4 pin plug.
Switcher ME (M/E, MLE)
Is a portion of a production switcher controlling a discrete video output; governing the selection of which input, transition type, and (potentially) keyer type is assigned to a ME output. ME’s typically have two rows of source selection buttons each; a preview row and a row which indicates which source is currently being sent to the ME’s output. Some production switchers have only one ME, while others can have two, three, four or more MEs. Switchers that have multiple MEs can send their ME’s output to a specific and dedicated destination (e.g.: projection screens, or a webcast) or the output of one ME can cascade into another ME to achieve layered effects.
A signal light within a eyecup camera viewfinder, or on a studio camera viewfinder, which alerts to the camera operator when his/her camera has been put on-air (Program). A tally indicator may also appear on a monitor wall to identify which camera is on-air.
A camera shot, centered and perpendicular to the primary talent’s shoulder line, at a tighter field of view than a “loose follow” shot. See the article, Camera Locations.
Pivoting a camera vertically, up and down, on a single axis. A shot in which the camera’s field of view moves vertically around a fixed axis point.
A numeric sequence of codes imprinted on a video tape or within video file. Timecode is used to reference specific content in a recording, and/or to synchronize devices or files. SMPTE timecode is a temporal representation of hours, minutes, seconds and frames. Subsets include: (a) Linear timecode (LTC) where timecode is recorded onto a dedicated audio track, (b) Vertical Interval Timecode (VITC) where timecode is recorded within the vertical blanking interval of a video signal, (c) burnt-in (or “vis” timecode) where the timecode digits are superimposed visibly over the video content itself, and (d) CTL timecode (control track) where timecode is written to a control track separate from audio or video.
A camera support device with three legs supporting a pan/tilt head.
A lever or knob on a tripod pan/tilt head which prevents panning, tilting or both from occurring. Typically engaged when the tripod is not in use, or the camera operator is not present or distracted.
A dial or knob on a tripod pan/tilt head which selects the amount of drag (friction) the operator feels when panning or tilting. Typically there are separate tension dials for pan and tilt.
Truck (Truck Left, Truck Right)
Similar to dolly, but instead of moving the camera closer/further from talent, “truck” is a side-to-side motion. Trucking is often accomplished with a dolly on track, or a slider.
A camera view including two subjects. Examples:
T number vs F stop
Feature film cinematography lenses are rated in “T numbers.” T numbers reflect a lens’ absolute light efficiency and transmittance. If two lenses have the same T number, they will both pass the same amount of light to the camera. F stop numbers (as found on still photography and video lenses) however express the speed of a lens based on a assumption the lens transmits 1OO% of the available light. Since F Stop numbers refer to a theoretically perfect efficiency, two lenses with the same F-stop rating may actually differ in light transmittance.
Video Operator (VO, Shader)
The live multi-camera production team member who is responsible for insuring the exposure, black levels, detail and colorimetry of each camera matches. Typically the VO accomplishes this with a color critical grade video monitor, a router, a waveform/vectorscope and a RCP or paintbox for each camera.
An intentional or unintentional visual effect whereby viewers see images through a perceived keyhole (the outer edges of the frame darker than the center of the frame).
Whip pan (Swish pan)
An extremely rapid camera movement from left to right or right to left, sometimes causing an image to blur during the movement.
Adjusting the colorimetry of a camera so that white captured by the lens is rendered as white, without a blue-ish or red-ish tinge.
White space (Negative space)
An element of aesthetic composition describing the intentional use of no objects, or blankness within a frame containing one’s subject. May also describe the placement of a subject within a frame, the amount of headroom, lead or nose room, etc.
Zoom (Zoom In, Zoom Out)
Variance of a zoom lens’ focal length from a wider-angle to telephoto, or vice versa, in one continuous move.
A zoom lens’ telephoto focal length divided by a lens’ wide angle focal length. A zoom lens with a telephoto focal length of 160mm and a wide angle focal length of 8mm is said to have a zoom ratio of 20x. With broadcast lenses, the focal length range is expressed as “20×8,” meaning 8mm is the widest focal length the lens can achieve, and 160mm (8mm x 20) is the telephoto capability of the lens.
[Special thanks to Mark Malburg, Bruce Coffy, Richard Curtis, Jason McKelvey, Stefan Svard and Ray A. Rayburn for contributing thoughts and content to this page]