So far we have discussed setting the time code in one camera but there are many occasions when two or more camcorders are on the same shoot. If each camera simply recorded its own time code there would be problems in editing when identifying and synchronizing shots to intercut. The basic way of ensuring the time code is synchronized in all cameras in use is by cables connected between the TC OUT socket on the ‘master’ camera to the TC IN socket on the ‘slave’ camera. Another cable is then connected to the TC OUT of the first ‘slave’ camera and then connected to the TC IN of the second ‘slave’ camera and so on although in a multi-camera shoot, it is preferable to genlock all the cameras to a central master sync pulse generator. This is essential if, as well as each camera recording its own output, a mixed output selected from all cameras is also recorded.
The TC OUT socket provides a feed of the time code generated by the camera regardless of what is displayed on the LCD window. A number of cameras can be linked in this way but with the limitation of always maintaining the ‘umbilical’ cord of the interconnecting cables. They must all share the same method of time code (i.e. free run or record run) with one camera generating the ‘master’ time code and the other cameras locked to this. The procedure is:
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Cable between cameras as above. |
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Switch on the cameras and select F-Run (free run) on the ‘slave’ cameras. |
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Select SET on the ‘master’ camera and enter the required time code information, (e.g. zero the display if that is the production requirement). Then switch to record-run and begin recording. |
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In turn start recording on the first slave camera, and then the second and so on. Although recording can start in any order on the ‘slave’ cameras, the above sequence routine can identify any faulty (or misconnected!) cables. |
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All the cameras should now display the same time code. Check by audibly counting down the seconds on the ‘master’ whilst the other cameramen check their individual time code readout. |
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During any stop/start recordings, the ‘master’ camera must always run to record before the ‘slave’ cameras. If there are a number of recording sessions, the synchronization of the time code should periodically be confirmed. |
Often it is not practical and severely restricting to remain cable connected and the cameras will need to select free-run after the above synchronization. Some cameras will drift overtime but at least this gives some indication of the time of recording without providing ‘frame’ accurate time code. Alternatively, a method known as ‘jam synch’ provides for a ‘rough’ synchronization over time with out cables.
The set-up procedure is:
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From the ‘master’ TC OUT socket connect a BNC cable to the ‘slave’ TC IN. |
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Power up the cameras and select free-run on the ‘slave’ camera. |
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On the ‘master’ camera select SET and enter ‘time of day’ some seconds ahead of the actual time of day. |
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When actual time coincides with LCD display switch to free-run. |
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If both cameras display the same time code, disconnect the cable. |
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Because of camera drift, the above synchronization procedure will need to be repeated whenever practical to ensure continuity of time code accuracy. |
Pseudo jam sync
Pseudo jam synch is the least accurate time code lock, but often pressed into service as a last resort if a BNC cable is damaged and will not work. The same time of day in advance of actual time of day is entered into all cameras (with no cable connections), and with one person counting down from their watch, when actual time of the day is reached, all cameras are simultaneously (hopefully) switched to F-run. This is obviously not frame accurate and the time code error between cameras is liable to increase during the shoot.
Reviewing footage
Broadcast camcorders are equipped with a memory, powered by a small internal battery similar to the computer eprom battery. It will retain some operational values for several days or more. There should be no loss of time code when changing the external battery but precautions need to be taken if the cassette is rewound to review recorded footage or the cassette is removed from the camera and then reinserted (see Setting time code, page 91).
Battery changes when time code locked
A battery change on the ‘master’ camera requires all cameras to stop recording if synchronous time code is an essential production requirement. A battery change on a ‘slave’ camera may affect any camera that is being supplied by its time code feed. If synchronous time code is critical, either all cameras use mains adaptors if possible, or arrange that a battery change occurs on a recording break at the same time on all cameras. Check time code after powering up.
Mini DV cameras
Note that DV time code circuitry is less sophisticated than many broadcast formats and may not be equipped with a regen facility. If a cassette is parked on blank tape in mid-reel, the camera assumes that it is a new reel and resets the time code to 00:00:00. There may not be an edit search/return facility and so after reviewing footage, park the tape on picture of the last recorded material and leave an overlap for the time code to pickup and ensure continuous time code. In all formats after rewinding and reviewing shots, inserting a partially used cassette, changing batteries or switching power off, use edit search/return facility to check at what point the tape is parked. Reset time code and zero CTL as required.