Open Focus Control (OpenFC) is a system for controling the focus ring and/or the zoom ring of a camera lens from a PC : it allows easy and cheap animation for stop motion or timelapses. It consists of a mechanical part, an electronic part and a software part.

The mechanical part – or drive module – of the OpenFC system is based on a stepper motor and a x30 demultiplication gear system. It can be constructed with a 3D printer or a CNC machine and easy-to-find components, which makes it very simple to construct.

Technical specifications:

  • Gear ratio: x 30
  • Resolution: 6000 steps per round or 0.06 ° per step (without micro stepping)
  • Weight: approx. 330 g
  • Size: 65mm (width) x 130mm (height) x 33mm (thickness)
  • Engine power: 6, 2V @ 0.67 A

The electronic part – or control module – of the OpenFC system consists of a stepper motor controller and an Arduino. It can operate autonomously or be controlled from a computer. It is compatible with DragonFrame, the stop motion software, and comes in two flavors, each of which can receive a power supply or a battery and a mini-joystick for real time control.

Electronic modules for the OpenFC system:

  • Standard module: module based on an Arduino Uno and a A4988 stepper motor drive card
  • Mini module: module based on an Arduino Nano and a type A4988 stepper motor drive card.
  • Joystick option: required to use the OpenMF system in real time
  • Battery option: required to use the OpenMF system without external power supply

The software part of the OpenFC system consists of several scripts and sketches designed to offer great flexibility of use and expand the possibilities of animation. This suite of scripts and sketches allows the OpenFC to operate in a live or in a programmed manner, in complete autonomy or controlled from a PC. In addition, it allows to use 3Dsmax to preview and/or produce frame-by-frame animations and allows the exchange of animation datas between 3Dsmax and DragonFrame

Software suite for the OpenFC system:

  • DFMoco: Sketch for Arduino to control the OpenFC system from DragonFrame (this sketch is developed by DZED society which publishes DragonFrame)
  • OpenFC4LIVE: Sketch for Arduino to control the OpenFC system in real time with a joystick
  • MAX2DF: 3Dsmax Script to export animation datas to DragonFrame
  • DF2MAX: 3Dsmax script to import an animation created in DragonFrame
  • DOFsimulator: 3Dsmax script to simulate the optical lenses operation.
  • OpenFCRig: 3Dsmax script to simulate the OpenFC system
  • OpenFC4MAX: 3Dsmax script to control the OpenFC system from 3Dsmax

All informations concerning the system are put online on this site, and are either licensed under Open Hardware for the hardware part or under Creative Common BY-NC-SA license for the software part.


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If you are interested and want to make yourself your own OpenFC system, just read the other articles : each one details an aspect of the system – prerequisites, mounting steps, tests, etc. Feel free to leave your questions, comments or tests.

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