On a video or film shoot, the job of a stagehand is similar but not the same as for a live performance. The audience is the camera, and the work on a shoot revolves around the camera.
In theatre the same large, elaborate setup is used for lighting an entire performance. There is a heavy use of color to create lighting effects, and the scenes flow through an uninterrupted sequence of preset cues. Scenery shifts from scene to scene.
In video, each take uses a unique setup, and the emphasis is on quickly setting up each shot, then moving to and setting the next. A few lights are commonly placed on portable stands which are focused for a take, then moved and reset for the next take.
A camera has a much narrower range of "vision" than the human eye, and the camera is much closer than a theatre audience. Therefore, effects are more subtle. Texture of the light is used instead of color; the balance of each light to the others is most important.
The typical lighting setup for a shoot is a three-light setup focused on the "talent", the people being filmed. This is called a Key and Fill system.
There are variety of fixtures used for lighting a shoot. A common feature is small size for portability and high intensity for sufficient illumination with only a few instruments.
Common key lights include small 1 kW fresnels called "peppers", and open-face units with small reflectors. These lights cast a sharp shadow.
Fill lights tend to be larger with more diffuse reflectors, like softlights; and kenoflos, which use banks of color corrected fluorescent tubes. On a remote shoot you might add a fabric diffusion unit, a Chimera Lightbank, to a key-type fixture.
Often it is desirable to soften a fixture already in place. A common expedient is to clip a sheet of diffusion media, such as Tuff Spun (spun fiberglass sheeting) to the front of the offending light with wooden clothespins. In fact, this practice is so common that spring-type wooden clothespins have a nic-name in cinema: C-47's.
Once the lighting is set, the first step is often to "white balance" the camera. Artificial light is never really white. Incandescent lamps, for instance, is actually mostly orange. Eyes adjust automatically but cameras must be TOLD what is "white". This is done by focusing the camera on a "white board" and adjusting internal filters until the card LOOKS white.
While there is still a lot of film shot, much camera work today is done on video tape. One of the best formats for professional work is Betacam-SP, which gives much higher quality results than VHS. There is a high-quality version of VHS as well but Beta-SP remains very popular for professional mini-cam work.
Video equipment generally uses 75 ohm coax cable, but instead of the screw or slip connectors found on home equipment, professional equipment is usually fitted with BNC (Bayonet Neill-Concelman) connectors, which are a positive locking connector which can be quickly connected and disconnected.
The talent may be miced using a handheld mic, but more often will be miked with a lavalier, a miniature mic element which can be clipped to the clothing at the neckline. Lavs can use a dynamic element but are more often condensers.
The person who determines the technical setup is the Lighting Director, or LD. He or she is assisted by the Gaffer, who is basically the Master Electrician. The Grip's immediate assistant is the Best Boy, who is the lead hand on the Electrics crew. The Electricians handle anything that is plugged in.
The Grips handle anything that is NOT plugged in. The Best Boy Grip is in charge of the grips, and also takes his orders from the Gaffer. Grips move the scenery, and Dolly grips push the wagons on which cameras are set for moving shots. Grips also work closely with the Electricians as the lights are set. The electricians set up the light stands, plug and focus them, and adjust accessories attached to the lights. The Grips set up and adjust the stands that hold flags, bounce cards and sheets, screens, and scrims that control spill and intensity.of the light.
"Electrics sets the light and Grips set the shade."
Video and film lighting instruments are similar to their stage counterparts, but usually are higher wattage for their size and have a higher "color temperature". Color temperature is a measure of how "white" a light is, measured in degrees Kelvin. Kelvin degrees are the same "size" as Celsius, but are measured from "absolute zero". Typical incandescent lighting is very red, about 2500 K. Stage lights are whiter, about 3200 K, and Video lighting is whiter still, about 3600 K.
Because they are higher wattage, video lighting fixtures "use up" circuits faster. For example, a typical stage or utility circuit is wired for 20 amps. At 120 volts, the maximum wattage is 20 a. X 120 v.= 2400 watts. A typical small fixture uses a 1000 w. lamp (1 kW). A 20 amp circuit can hold two of them without overloading. However, only one 1.5 kW lamp (1500 w.) can go in the same circuit, as two will equal 3000 w., or a 600 w. overload. The circuit can also hold a 2kw load, with 400 w. to spare. Many location shots have only a few circuits available, so the electricians must keep track of the loads on each to prevent tripping the circuit breakers.
During a take, it is very important that everyone keep quiet. An extraneous noise or conversation, picked up by a mic, can ruin a take.