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The term 'Moco' is short for 'Motion Control' (wikipedia). In general motion control is precise mechanical movement of objects, in our case the object is a camera. The basics of photographic or cinematic motion control are to achieve predictable accurate camera movement and thus smooth changes in point of view. Moves can be made up of a pans (horizontal turn), tilts (vertical turn), dollys (linear travel), rolls (circular camera movement), booms (long arm cantilevers) or any combination of these movements. Photographic and cinegraphic moco can also include control of lens functions such as zoom and aperture. The apparatus that makes all these automated movements and adjustments possible is typically called the 'rig' (which can also refer to non automated or hand driven camera apparatus). The size and complexity of motion control rigs can vary quite a bit from simple pan heads controlled via dials to massive multi dimensional rigs controlled via software.
Example of high end motion control rig:
Time-Lapse
There are a plethora of applications for moco rigs. The one I'm most familiar with is time-lapse motion control, which allows the shooter to setup a very gradual movements over a long time periods. For example, let's say we have a rig set for a horizontal pan traveling 90 degrees over the course of an hour. Now lets say the camera is set to take shots at 6 second intervals resulting in 600 frames in that hour time period. When compressed to the standard 30 frames per second playback speed this will result in a 20 second video sequence that pans across a scene 90 degrees. This effect adds a three dimensional aspect to the time factor as if the camera was being handled. I find it mesmerizing and that it engages the viewer, pulling them actively into a scene.
Example of time-lapse motion control:
Special Effects
When used for special effects a moco rig will be programmed to do a series of movements and then repeat these movements accurately. This allows various elements to be recorded independently and then combined in post (post production). For example an actor captured on a green screen and an 'on site' shot for environmental background. A moco rig can be set up in both locations and repeat an exact series of motions. The two shots are easily combined (using ‘keying’ on the actor) allowing the actor to appear as if they were in the scene. Think flying shot from a rooftop with Angelina Jolie teetering on the edge. The motion control rig can shoot the rooftop scene, then shoot Angelina safely on a green screen floor and thus combine the two for dramatic effect. Furthermore it’s possible to import the camera’s motion path into computer graphics programs and add say the helicopter crashing into the building just below the teetering Jolie. The layers that can be added are only limited by the imagination and the accuracy of the rig.
High end motion control showreel showing post production results:
Gigapan
Yet another application of moco rigs is in the emerging technique of ‘Gigapanorama’ (or Gigapan) photography (gigapan website). This process uses a pan and tilt rig to capture an array or grid of a scene by positioning the camera in a series of rows or columns. The resulting frames are then ‘stitched’ or ‘blended’ together to create an extremely high-resolution single image. The result allows the viewer to explore a static scene to minute details.
The gigapan moco rig explained:
Spherical IBL
A similar technique to Gigapan photography that uses moco rigs is spherical photographs or virtual reality photos. In this case the array or grid of shots encompass a full 360 degrees allowing the viewer unlimited exploration of a scene from the camera’s single point source. When the spherical scene is captured with high dynamic range (or HDR) this type of photo can be used as image based lighting (or IBL). Basically the image can be imported into computer graphics applications and replicate the environmental lighting, reflections, and background of a CG scene thus increasing the realism dramatically. Many high-end special effects firms use this technique in co-ordination with a motion-controlled camera to help their computer generated objects to look and feel as though they are a part of the ‘real world’ footage.
Sample of sphereical HDR image based lighting in action:
Future
In my opinion motion control as it relates to photography and video will continue to evolve into new and exciting techniques far beyond what we know today. The primary goal of openmoco.org is to get this amazing tool that is typically out of reach due to cost and complexity into the hands of independent filmmakers, enthusiasts and professionals alike. Moco systems are typically proprietary as well restricting flexibility and innovation. By creating an open source community based project we hope that users will build upon and modify the software and systems to fit their needs and learn from each other’s creative endeavors.
Jay Burlage (aka 'milapse')