Remote Follow Focus

[Avenger007]

After waiting too long for M2 to release their Remote follow focus, I've decided that its time to go the DIY route. I've been trying to research the Bartech/Polamar system among others but its a very slow, difficult process.

I wanted to know if anyone here has taken a stab at a RFF whether it be RC motors or belt drives or whatever. Some reference points would be great. I'm sure theres a few of you on here that have dealt with these motors. Shelling out $4k for the pro stuff is not an option yet.

Ive been thinking about using Lego Mindstorms (robotics) for the parts. They have a newer NXT line out that has a ton of programmability. The parts are also readily available online and cheap.

 

[Postmaster]

I assume you want to use it with 35mm adapter and lenses.

Why not take the usual rings, make a simple bracket that holds a servo (step) motor with cockwheel between the rods?

You can get that stuff as industry standard components for linear technic, if you want it real beefy or go in a shop for RC Cars.

I never understand why companys need so much time and "R&D" to come up with solutions that are so simple and common in every toy RC car since generations.

Frank

 

[mikkowilson]

I never understand why companys need so much time and "R&D" to come up with solutions that are so simple and common in every toy RC car since generations.

Because of the precision needed for our application. You mess up FF and it will show in the picture quickly.

RedRock probably thought the same thing when they announced their unit ... only to later find that you can't just use stepper motors, as they have backlash and stutter when turning "backwards". Oops.

You need continuous motors [with super-precise positional feedback], and the circuitry to control them. And then the radios to [super reliably, in a multitude of RF conditions] link that control to a precise remote interface. And then make it robust & reliable enough for life on a film-set.


- Mikko

 

[Avenger007]

I still have more experimenting to do with the legos but Its looking like it will not work. I dont think the motors will be powerful enough.

For those not familiar with the mindstorms set, it is a kit that lego released a few years ago where they include a control unit that is programmable through PC software and a few motors/sensors that work together to control a robot of your creation. My thought process was to use the control unit in conjunction with one motor on the camera (both of which are lightweight) and program the motor to turn from a variable knob. But looking at the pieces I dont think the plastic will translate well on set.

 

[Bob Hill]

I'd like to echo Mikko's sentiments. The motors and controllers commonly used for R/C vehicles are not precise enough nor are the radio controllers for the demands of a FF unit. You would have to go to much much tighter toleranced motors, gears, motor controllers, positional sensors, etc. to get a truly functional unit.