Wednesday, July 25, 2012

GBTimelapse - Two Axis Dolly Control

The Question
Several time-lapse experts have asked: how can we use GBTimelapse AutoRamp with the Dynamic Perception MX2 dolly in two-axis mode - a combination of linear moco with pan/tilt?  Previously, this wasn't possible because, the GBTimelapse/MX2 USB connection precluded the use of a pan/tilt head like the Merlin.

The Solution
Now there's a simple method: just connect your camera to the MX2 dolly engine using a special PC sync cable. With MX2 firmware version 0.92 installed (thanks to Jay Burlage), the dolly will move one step whenever the camera shutter closes.

About the cable you'll need
A PC cable connects the camera to the MX2 Dolly Ext 1 connector by means of hot shoe and PC sync cable. It’s not a standard PC cable - it has a PC sync connector on one end and a TRS connector on the other. TRS (tip, ring, sleeve) is also known as a “mini-stereo” or headphone connector.

This cable is available from Promote Control for about $30. You don’t need their HDR controller. All you need is this cable.

To configure the MX2
  1. Go to the Settings menu
  2.       set “Motor S1.Mod” to “Interleave”
  3.       set “I/O 2” to “Ext. Interval”
  4.       set “Invert I/O” to “On”
  5. Optional: Under the Camera menu, set “Exp. Delay ms” to “1000”
  6. Set the main screen to “Ext” and set a step distance

Within GBTimelpase no configuration is needed. The dolly will move one step after each exposure is completed. 

Below is a very cool video by Mike Lanfor using GBTimelapse, a 5D Mk III, the MX2 and a Merlin pan/tilt head. As he says, he had to abort the test when the lightning got too close for comfort! Thank you, Mike!

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