Canon Lens Connections
Canon ENG type lenses with a “virtual” port can be connected to Previzion by using a data splitter box made by Lightcraft.
Only Powered Axes are Encoded
Only axes with internal servo control are encoded. To check this, underneath the lens controllers, there are toggle switches that go from “Manual” to “Servo.” The lens must have a manual/servo switch for both zoom and focus in order to read both zoom and focus data.
Finding the Remote/Virtual Port
Click the image above for a larger view. The lens data splitter box connects to the Remote/Virtual port, as shown in this image.
Passive Data Collection
Previzion does not drive the motion of the lens. The lens motion is controlled in the usual way, either by an operator directly moving the lens (with the lens servo switches set to manual), or remotely with a wired zoom or focus demand.
Canon Zoom and Focus Demand
The Lightcraft lens data splitter for Canon cameras lets standard Canon zoom and focus demand controllers control the camera as in normal operation, while sending out the lens position data to Previzion. The image above shows the standard Canon FPD-400D and ZSD-300D lens demand controllers attached.
The lens data splitter is connected to the Remote/Virtual port, and the zoom or focus demand is connected to the matching port of the back of the data splitter box.
There is an additional demand port on the Canon lens that the zoom or focus demand is connected to in the usual manner. In this way, traditional zoom and focus demand controls can be used while still reading the real time lens motion data for Previzion
Connecting to Previzion
Connect the 4 pin Lemo lens port on the Airtrack to the 4 pin Lemo lens port on the data splitter box with the same 4 pin to 4 pin cable used to connect the Preston lens controllers to the Airtrack lens port.
Inside Previzion, select Canon from the lens drop down menu. The light will go green if the lens is present.
The Canon lens encoders are high precision 16 bit encoders, but they are incremental. When the lens is first powered up, it needs to be moved through its full range of zoom and focus information to properly zero the encoders; the scene will “pop” visibly under motion until this is completed.
Older Lenses May Not Be Encoded
When using older lenses, IASD (Potentiometer Type Drive) Lenses do not work with Previzion. Only Encoder Type Drive Lenses will work (labeled “SE”, like IASE or IRSE lenses).