Home made remote follow focus

[hoarp001]

hi,

Im steadicamming on a low budget film at the moment, using the SGpro adapter. The production didn't see the importance of hiring a remote follow focus so we have been struggling with a very out of focus image on the steadicam. We tried doing marks on the focus wheel and gently changing it but it screws up the steadicam ballence instantly. I got home from the shoot last night, and within half an hour, had made this, and Im pretty pleased with it.

Its an RC servo attached to a 0.8mod gear. It is actualy the spur gear from a traxxas Tmaxx nitro RC monster truck. This is attached to a servo tester I made years ago, it was actualy made to control the throttle on the engine of a wind machine that I built.

It only moves the lens about 90degrees, but thats enough to get it from infinity to 4 feet, which is more than what we need. The plan is to do the focus marks on the follow focus wheel, then move the lens to those marks using the knob on the box, so the focus puller will stand next to me as I oerate and move the focus that way.

http://uk.youtube.com/watch?v=_ImlfgySmIg

[alekstef]

its kind of noisy... but awesome!

[AftonGrant]

Nicely done! Not bad at all, considering the circumstances under which it was made. Obviously this can't be a permanent solution, but for your problem, it will definitely help.

What surprises me is that productions sometimes don't realize the cost of renting the proper equipment to do the job far outweighs the cost of reshooting or ending up with sub-par footage. In a few weeks or months, when they're cutting the footage together, they'll be looking through all the out of focus stuff saying to themselves, "You mean we could've spent an additional $100 and it would've solved this problem? Why didn't we???!!!"

[Erik Olson]

Afton,

Have you tried or worked with the Varizoom I/F remote (http://www.varizoom.com/products/controls/vzwff.html)? It is a single-channel 900MHz like the Preston, but I don't see things like auto-calibrate features in the product literature.

Mine would be a back-up to the Preston and for jib work where the full Preston is overkill / inoperable by a single jib operator.

http://www.varizoom.com/img/products/vzwff_receiver_large.jpg

e

[hoarp001]

The cost of hiring the remote FF was minimal anyway, a fellow steadicam operator in LA offered to lend me a 3ch system (although we would only use the focus) and the receiver and motor for free, we just had to cover te cost of shipping which was £200 in total for the four weeks. For £200 you could hire a bartech for two days and they turned it down for the three weeks :Drogar-Love(DBG):

[AftonGrant]

Afton,
Have you tried or worked with the Varizoom I/F remote? It is a single-channel 900MHz like the Preston, but I don't see things like auto-calibrate features in the product literature.

Mine would be a back-up to the Preston and for jib work where the full Preston is overkill / inoperable by a single jib operator.


That Varizoom controller was developed by Jim Bartell - owner of Bartech Engineering, and maker of the Bartech devices. The Varizoom is essentially a Bartech with a different nameplate. I own two Bartechs, so in a sense, yes, I have used the Varizoom. Opinions about the Bartech are well documented. It has been an industry standard for many years now, and continues to be an extremely simple, reliable piece of equipment.

Also, just to clarify, the Preston is not a single-channel, 900MHz system. It's a 30 channel, 2.4GHz system.

[Erik Olson]

Ah, thanks! Is the 900MHz the spec I read on the Bartech then... I guess that makes more sense. So, if that is effectively a rebadged Bartech, do you know how it compares from a pricepoint? Equal? 30% less?

I'm familiar with Preston's pricesheet, but can't seem to find Bartech's. One phone call would resolve that, I suppose...

:)


e

[Kwan]

Nice one Hoarp001
I have almost same setup with Varizoom (MC100 Remote Head) Motor.

[AftonGrant]

So, if that is effectively a rebadged Bartech, do you know how it compares from a pricepoint?

They're about equal. Both around $4000 for single channel and motor (Bartech does not make motors).

[Postmaster]

hoarp, may I ask what´s inside that controller box?

Thank´s, Frank

Edit: forget it, just scored a servo tester on Ebay.

Thank´s anyways, Frank

[hoarp001]

Yeah, servo tester.

This is the gear you need:

http://cgi.ebay.co.uk/TRAXXAS-T-MAXX-72T-32-pitch-SPUR-GEAR-P-N-4472_W0QQitemZ300206940584QQihZ020QQcategoryZ34063 QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

[Erik Olson]

They're about equal. Both around $4000 for single channel and motor (Bartech does not make motors).

The Bartech site indicates that this particular model is modular and could be expanded. I suppose that the same goes for the rebadged model?

e

[AftonGrant]

Yes, they are both modular. This simply means you can have as many or as few channels of control as you wish. For each desired channel, you need to have an additional kit, but they are built to work together seamlessly - and they do.

[Neal Buconjic]

Damn it, when is Redrock going to work the bugs out and release their $500 wireless FF?

[alekstef]

Damn it, when is Redrock going to work the bugs out and release their $500 wireless FF?

500 bucks? Damn.. I can't wait! Can it be used with other adapters than the Redrock adapter too?

[Neal Buconjic]

http://www.redrockmicro.com/microRemote.html

[alekstef]

I might have overlooked something, but I don't think that link answered my question? :)

[Erik Olson]

I recently received an update from RedRock Micro regarding my three reservations for this item. Effectively, it isn't happening anytime in the near future. That was the tone of the note.

Ah well, there's always the $8k options!

e

[Car3o]

back to subject at hand and not red rock's follow focus. i'm interested in building one for myself.

would this work to move it back and forth?

http://cgi.ebay.com/Esky-EK2-0907-Servo-Tester-w-Free-Gift_W0QQitemZ290217606133QQihZ019QQcategoryZ34056 QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

what kind of servo is best suited for this?

thanks,
-Rh

[Jason Miller]

car3o, yes it should, that is a basic servo tester which should give you pretty close to a 1:1 turn of the servo. you'll need a batt pack, or just pick up the wires at servo city, or parallax.com and hack in a 6v ac to dc power suply.

[Car3o]

this will be my next diy. seems a whole lot cheaper and easier than to build an actual ff.

hoarp, what servo is the best? i know you're trying to market these and probably don't want to give out too much info, so if you have suggestions, that'd be great.

-rh

[hoarp001]

My servos and controllers are modified. The standard servo controller only moves a servo 90 degrees, but a servo is capable of moving 180 degrees. My system increases the astable pulse so the servo can move through its full 180 degree movement.

With servos, just dont buy cheap crappy ones, spent some money.

[Jason Miller]

so you have a servo extender on it, or is ti a internal mod?

[hoarp001]

Well i built the control board myself, I just build it to use the whole servos motion. A normal servo controller only uses 90 degrees because thats all a radio transmitter system on an RC car (or similar) uses.

[Car3o]

guy at the hobby shop seems pretty interested in helping out on the project. he says he's done it numerous of times playing around. so that's good news. he's got spare parts lying around so that'll cut my cost in half to nothing.

also for those that are intersted. i found this

http://www.servocity.com/html/180o_servo_stretcher.html

[Jason Miller]

I've been looking at that servo strecher, but for the most part if I do remote FF it will be for my moco rig so I'll have the computer control the focus and maybe the zoom, this will be for just the camera, not an m2, so I'm wondering if there is a good way to get my computer to control the camerra built in focus and zoom motors?

Jason

[hoarp001]

Mm that servo stretcher is cool but my control board will use 180 degrees anyway....

[Jason Miller]

hoarp001 with the strecher you may get 270 or even 360

[hoarp001]

You cant get 360 degrees with a standard servo, it wont phsycialy move that far, it has notches on the gearing that restrict it to 180 degress

[Jason Miller]

oh I disagree, I have standard servos running my pan tilt, and the just keep turning and turning, non stop when controlling them from the computer, at some point at about 9 or 10 revolutions they start to slow down a bit.

it isn't the gearing that limits there motion its the chipset.

[Car3o]

jason, what servo allows that? and is there a diff stretcher you use? plus, would you have to get another servo controller to allow 360 rotation?

[Jason Miller]

I use hitec servos

[Car3o]

do you use a different servo stretcher to make it a 360 rotation?

[Jason Miller]

I do not have a servo stretcher, I use the parallax usb servo controller,

but even when I'm using the joystick that came with the servos I get almost 360 degrees on each of the pan tilt servos,

not all servos have gears, they are simply dc motos with pretty basic stamp controllers which allow for error inputs when they will strive to fix.

Jason