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Procam dictionary of camera terms and definitions

F Stop

The F stop of a lens signifies how wide the aperture (iris) can open. The lower the number, the bigger the aperture and the more light that can enter the lens. This is directly proportional to the depth of field. The lower the F stop, the shallower the depth of field.


T Stop

The T stop of a lens signifies how much light can pass through the lens. Unlike an F stop, a T stop takes into consideration the transmission of light through the lens. A T stop value of a lens is higher than the F stop value of the same lens, eg. a 50mm EF Canon Prime lens rate at f1.8 is also rated at T1.9.


Focal Length

The focal length of a lens signifies how wide or long the lens is. The lower the focal length, the wider the lens e.g a 28mm lens is wider than a 200mm lens. A 16-35mm lens is 16mm at the wide end and 35mm at the long end.


IRIS

The iris is the physical part of the lens that opens and closes to let light pass through. Like the iris in your eye, the larger the opening in the iris, the more light that is being let through the lens. The iris not only controls how dark or light a picture is, but it also controls the depth of field of an image.



DEPTH OF FIELD

The distance between the nearest and the furthest objects giving a focused image. A shallow depth of field is achieved by opening the iris on a lens, or zooming in on a zoom lens.


PRIME LENS

A prime lens has a fixed focal length and they are hired in sets of 5 or 6. Each set is different but in general covers a broad range from a wide lens to a long lens.


Zoom Lens

A zoom lens has a variable focal length that can move through any focal distance within its range. E.g a 16-35mm lens can be at any focal length between 16mm at its widest to 35mm at its longest.


BOKEH

Bokeh is the aesthetic quality in which a lens renders out-of-focus points of light. In the below images, the Bokeh is the way the lens interprets the spots of lights. These can be circular or oval depending on the character of the lens.




VIGNETTE

The area towards the edge of a frame which softly fades to black.

Lens Mounts

Lenses have mounts to attach them to a camera. The type of mount depends on the size of the sensor that the lens needs to cover. The most common in a studio/OB environment is a B4. For a 35mm shoot, the most common is a PL or EF.


Lens mount adaptors

You can use a lens mount adaptor to fit almost any type of lens to any camera. There are some compromises though when doing this, including light loss, vignetting and ramping.


Recording Information

This varies hugely depending on the quality of the record, frame rate and resolution. In a standard BBC compliant XD-Cam, HD recording at 50i, you get 90mins of record for every 50GB of storage.



Codec

A video codec is a means of compressing a video file. This makes the file size smaller and more manageable. Some popular codecs:

  • MXF
  • Prores
  • DNxHD

RAW

A RAW video file is an uncompressed video file. RAW files are mostly used when a lot of post-production is required on the final product.


PROXY

A proxy file is a low-quality copy of an original. 


RECORDING TIMES

This varies hugely depending on the quality of the record, frame rate and resolution. In a standard BBC compliant XD-Cam, HD recording at 50i, you get 90mins of record for every 50GB of storage.


Recording Formats

TV Resolution

Resolution is a term used to describe the number of pixels that are needed to make up a picture. In UK broadcast these are standardised as:

  • SD - 720 x 576
  • HD - 1280 x 720
  • FULL HD - 1920 x 1080
  • 2K - 2048 x 1080
  • ULTRA HD - 3840 x 2160
  • 4K - 4096 x 2160


PAL

A historical term to denote what your analogue colour TV region was set to. PAL shoots at 25 frames or 50 fields and was used in the UK. This term is still used to indicate that the production is shooting at 25FPS.


NTSC

A historical term to denote what your analogue colour TV region was set to. NTSC shoots at nearly 30 frames (29.97) or 60 (59.94) fields and was used in the USA. This term is still mostly used to indicate that the production is shooting at 30FPS.

ASPECT RATIO

The proportional relationship between a picture’s width and height. The most common aspect ratio is 16:9 which is used in HD and UHD television. 17:9 is also used for a more cinematic feel to a production by using DCI 2K and DCI 4K resolutions. Anamorphic or 2.39:1 is used mostly in cinema, however, it is becoming more popular in TV.



SD

Standard Definition. SD video formats are mostly used in transmission and are broadcast at 720x567/50i in the UK.


HD

High Definition. HD video formats are currently the primary acquisition format in the UK. HD is also a very popular transmission format with every major broadcaster having at least 1 HD channel. HD resolution is 1920 x 1080 and has an aspect ratio of 16:9.


2K

2K resolution or 2K DCI (Digital Cinema Initiative) is a very underutilised resolution. Given the aspect ratio of this format, it lends itself to a cinematic feel as the picture is slightly letterboxed compared to standard HD. It is underutilised due to the popular use of its bigger brother 4K DCI. 2K DCI’s resolution is 2048 x 1080 and its aspect ratio is 17:9.


FRAMES

A frame can be thought of as a still image. Many frames played one after the other gives the appearance of a moving image. In HD a frame has the resolution of 1920 x 1080.

UHD

Ultra High Definition. UHD video formats are becoming more and more popular with camera and monitor technology improving every year. UHD has a resolution of 3840 x 2160 an aspect ratio of 16:9, and should not be confused with DCI 4K.


4K

4K resolution or 4K DCI (Digital Cinema Initiative), is a 17:9 version of UHD. This gives a slightly more letterboxed image compared to UHD. 4K DCI’s resolution is 4096 x 2160 and its aspect ratio is 17:9.


DCI

The Digital Cinema Initiative was created in March 2002 and is a joint venture of Disney, Paramount, Sony Pictures Entertainment, Universal and Warner Bros. Studios. DCI’s purpose was to create a standard for digital cinema that ensures a uniform and high level of technical performance, reliability and quality control.





Horiztonal


Vertical


Aspect Ratio

Analogue NTSC6404804:3
Analogue PAL7685764:3
HD 720128072016:9
HD 10801920108016:9
2K2048108017:9
4K UHD
3840216016:9
DCI 4K
4096
2160
17:9
5K
5120
288016:9
DCI 6K
6144
324017:9
8K UHD7680432017:9
DCI 8K8192432017:9
16K15360864016:9
64K UHD614403456016:9


Fields

A field is an image that contains only half of the lines needed to make a complete picture or frame. 2 fields make up a frame. The first field displays the odd numbered lines in a frame and the second field displays the even numbered lines. Fields are utilised in interlaced scanning.


Progressive Scanning

Progressive scanning or ‘P’ e.g. 25P, is a way of displaying moving images. In a 25P clip there are 25 frames per second. 


Frame Rate

The number of frames that are captured every second. UK broadcast shoots at 25 FPS (Frames per second), America at 30FPS and cinema or international footage is generally shot at 24FPS.


Interlaced Scanning

Interlaced scanning captures a video frame across 2 fields. Each field captures half the information that the frame captures and these fields are interlaced back together to represent 1 frame. At HD 25FPS in interlaced this would be represented as “1080 50i” or “1080i/25”. When played back, the fields are run at 1/50th of a second each giving a smoother motion.


PsF Scanning

With Progressive segmented frames, a progressive frame is divided into 2 identical fields (odd and even). This technique allows for a progressive picture to be represented in an interlaced workflow. Unlike interlaced, as both fields are identical there is no motion blur.


Multicam

TX

Short hand for transmission.


RX

Short hand for record.


Camera Channel

The camera system that is used in a studio or OB. The camera channel normally just refers to the type of camera rather than the accessories like lens, ped, or grip that it needs.

VT

Short for Video Tape. Used in a studio or OB to reference a clip that will be played into a live or as-live broadcast.


Vision Mixer (equipment)

A piece of equipment used to select which camera, VT or video source is selected for a live or as-live broadcast.


Line cut

A studio or OB term to refer to the finished record of a live or as-live broadcast.


ISO

A studio or OB term to signify that a camera is being recorded in isolation. This means that no matter what a vision mixer or director cuts to in the vision mix, the ISO will constantly record that 1 camera or source.


Timecode

Used to stamp a time onto every frame of recorded video. Free running time of day (TOD) is mostly used, however any time can be used depending on the production. Once the timecode is written with the video frame, it can be cross referenced with other media using the same timecode to find the same point within the record. This is especially important when there are multiple cameras being recorded and taken in to an edit so that the editor can find the same point in the record to cut to different cameras.


Fibre Optic

Fibre is used to streamline the cabling in an OB or Studio. It is used for cameras, audio and data. One length of fibre can run multiple signals through it. Not only does it make rigging and de-rigging easier, but due to fewer cables, it makes the rig a lot neater.


PSC

Portable Single Camera. A PSC shoot is normally a documentary camera style shoot where only one camera is used to capture the event or moment.


ENG

Electronic News Gathering. An ENG crew is normally a one or two man crew who work on fast turnaround for news events or sports inserts.


SDR

Standard Dynamic Range. The contrast seen on most TV’s since the invention of the CRT monitor. 


HDR

High Dynamic Range. HDR shooting gives big contrast ratios, offering the viewer brighter whites and darker blacks. To view HDR you need to have an HDR TV.


LOG

Used to capture HDR footage.

Sensor Information

Sensor

The camera sensor is what turns the light from a lens into an electrical signal that is then processed to display a picture. Sensors vary massively between cameras and models of cameras. The larger the sensor, the shallower the depth of field. However, a larger sensor doesn’t necessarily mean high resolution or quality.


35mm sensor

A term that refers to the size of standard photographic film format. This term is now associated with a more cinematic style of filming in TV.

Until recently all TV broadcast cameras used a sensor that is smaller than 35mm. The C300 (2011) was the first mainstream camera for broadcast that utilised a 35mm sensor (excluding the F3 that was released in 2010). There are now five or six mainstream cameras, including the FS7, F55, Amira and C300 MK2 that all have 35mm sensors. 


2/3in sensor

Size of sensor used in shoulder mounted and standard studio cameras.


BBC HD standard

The BBC issued guidelines for an HD standard of video acquisition. There are many points to this, but the main one is that the camera sensor needs to be larger than 1/2in and be recorded at a compression rate higher than 50mb/s. Most other broadcasters adopted these standards too.


Vision / Racks engineering

Racks engineering is a centralised area within a studio/OB where the operator has control of the camera irises and paint functions. The racks engineer matches each camera so that as the cameras are cut into the vision mix they match.



Grade one monitor

Used as a master monitor on set to check that all video feeds match each other.


Waveform / Vectorscope

Used alongside a grade one monitor to help match camera pictures to each other.



RF

Shorthand for radio frequencies.


RF Licenses

Needed for use of any wireless audio, video or data systems. There are some exceptions to this however for a reliable wireless system an RF license is required.


Lighting

Tungsten

Type of bulb used in a lighting fixture. Tungsten bulbs are being phased out, as they are bad for the environment due to their power consumption.

HMI

Hydragyrum Medium-Arc Iodide Lamp. This tongue twister is a light bulb. It gives a cool daylight colour and is more power efficient compared to a Tungsten bulb. 

LED

Light Emitting Diode. A widely used type of lighting due to its lower power consumption and colour correction.


Fluorescent

Fluorescent lighting is a low power lighting source. Usually found in strip lighting. It is being used less and less due to the introduction of good LED fixtures.

IR

Infra-Red. IR lights area used in conjunction with night vision cameras. IR lighting is invisible to the naked eye, but with the use of special cameras you can effectively see in the dark. IR cameras generally show IR in a black and white or green image.


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