Follow focus update

Some more parts for the follow focus came today, and things are starting to fall into place, so here's what I've got right now:

Here are all the parts, just laid out.

Here the lens is on the frame (rod system) in approximately the position it will be when mounted on the camera.

 Here are two phoctos of the gear used. The pitch is 0.08" (MXL)

Detail of the handle mount, press fit. (Also surprisingly strong!)

Close up of the drive belt on the lens focus ring

More of the same

This is how the whole thing will work, I will just slide that white mounting plate in, and mount the stepper motor on it (when it gets here), and mount the gear on the motor. The calipers are just to show size and to hold the gear in place.

Here it is from a different angle.

 That's where things stand right now, and so far it's working nicely. The new stepper motor should come soon. I ordered one from MPJA.com, only to be told that that model was not in stock, and the listing was a mistake. :( Oh well, they offered a different model that I think will work, for the same price, so I'll give that a try, and see how it works. The main thing is that I want it to run on 12 VDC, and have enough torque. The motor runs on 12 V, adequacy of torque awaiting testing.

 I can't really use it with the stepper motor I have right now because (1) I haven't figured out a good way to get enough torque out of it without blowing the driver transistors, and (2) it has a gear permanently affixed to its shaft, (of the wrong size) so I would have to cut it off to get it to work with the gear and drive belt.

 Just for reference, here are the parts used for the follow focus:

Gear: https://sdp-si.com/eStore/PartDetail.asp?Opener=Group&PartID=58730&GroupID=217

(Or similar, exact specs not important unless you are trying to get a ratio right)

Belt: https://sdp-si.com/eStore/PartDetail.asp?Opener=Group&PartID=51264&GroupID=213

(Or similar, length may be changed to suit application)

I didn't calculate the reduction ratio for the focus, because for now I don't need to, and it would add a lot of complications. I'm just going to get the whole thing working before I worry about that. After I have it working I can calibrate a dial, and tweak the ratios in the software. If at some point I try to make a commercial version, I may start thinking about things like that.

Hopefully I'll have the 3rd version of the .blend file ready to be posted soon, but that's all for now, until next time! 

Camera rig

I've been working on a 15mm camera rig. A follow focus will be essential to this project, and I'll need something to mount in on once I make it, so here's what I've got so far:

The rods were from http://www.onlinemetals.com/ if I remember right, and so was the plastic. The photos should make the design so far clear. The plastic parts were cut from this plastic, 3/4" I think. Hey, it was the cheapest option by far and it works great! I cut the sections shown from a 12 X 12" piece, and this took 36 square inches (3X12) to make two brackets. I can make smaller brackets, but I wanted to make a larger one for the camera first, and I can always swap out brackets later. The measurements are 60 mm rod spacing, and 15 mm (approx., it's slightly off, but not much) diameter rods. The reason I built it to these measurements is that is what commercial DSLR rigs are using, so if we ever happen to acquire a 15mm rod accessory, (which is unlikely, as the prices are astronomical!) it should be compatible with commercial systems. I'm not the only one building or who has built a DSLR rig though, but I'm the only one who has posted it so far (hint hint, Daniel!) Next I need to work on making this into a shoulder rig, with a counterweight and shoulder pad, or I could just use it on a tripod as its main function will be for the follow focus.