When we shoot with a rented camera – which happens quite a lot – I ask to have it delivered a day in advance so that it can be balanced on the gimbal.
Here’s a quick explanation of what that involves.
To be correctly balanced, the camera must sit straight on all axes while the gimbal is unpowered, i.e. it must not tip forward or back, or left or right. Furthermore, the camera should be able to be moved to any position in the pan, tilt, or roll axes, and stay in that position.
The reason for this is that the gimbal servos or motors which stabilise the camera during flight, must be doing the minimum amount of work possible to keep the camera level. If they are struggling to hold an unbalanced camera to horizon while also stabilising the movement of the aircraft and actioning the commands from the camera operator, then you will not come out with a satisfactory piece of video.
This process can be quite tough, as once balance is achieved on one axis, often this upsets balance on another axis. What often follows is a quite bit of tail-chasing and lots of allen key work, in order to get every axis happy. Balancing the pan axis is another thing altogether, and involves hanging the whole aircraft sideways, balancing the CoG of the gimbal and camera, so that it will not swing or rotate at any point.
Following the balancing procedure, the gains of the servos / motors have to be set. Changing these gain settings will alter the ‘responsiveness’ of the motors to react to aircraft movement in order to keep the camera level. Too low, and the camera will be too slow in stabilising and the shot will suffer. Too high, and the axis will ‘jitter’ as if it’s had too much coffee, again ruining your shot. These settings are changed by hooking up the laptop to the gimbal, testing the camera’s response to movement, changing the settings, testing again, and so on. The secret is to have the settings as high as possible, but without any jitters. Stabilising while also responding to a command from the Cam Op often create more judder, so it’s a fine line between right and wrong and you need to check in every scenario!
This whole ‘balancing act’ can take several hours or more on some occasions, which is why we ask for the camera in advance. From experience in our early days, doing this whilst on set, and while the clock is ticking, is not a good idea!
It’s much nicer to show up on the day knowing everything’s ready.
Click below to see a timelapse of Chris balancing a Canon 5D with 24mm prime lens.