DIY Follow Focus

M

m_bass

Active member
Before anyone asked it has not been built or tested. Just an idea I had. The cost should be well under $100 to build, but I will not be able to make one for a few months. “I am moving to Chattanooga TN next week and have to pack up my tools. By the way does any one live that way.” The main gear is from an r/c helicopter I think. It can be found for 6 bucks or so. It is designed with built in stops and if you push the center of the knob you can go into macro. It connects to the lens either by belt or friction.

Basically I was looking for any thoughts on the design. If any one wants to take the first leap on building one, let me know. I have dimensions and some part # for the gears…
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Re: DIY Follow Focus

Right now I have it attached with a plate and rods like Jarreds. The drawing also has removable pistol grips and shoulder mount. All the parts can be made with a drill press, chop saw, and a tap and die set.
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Re: DIY Follow Focus

I like it. Should work well if gearing is both tight and ultra quiet. I wonder about the two sizes you chose for the gears. Its hard to say if its the right ratio because we dont know what the diameter of the lens is going to be and every film lens has a different length the focus ring travels. Ideally you want to be able to go from Infinity to the film lens minimum focus with little more than a half turn on the follow focus knob. Now if you plan on only using this for the standard DVX built in lens then you could find the ideal gear ratio. Otherwise it could be difficult to use on some lenses while others will work extremely well. I guess the ideal would be to have a swing arm with a additional gear that could be changed out for different sizes. Perhaps Im being to picky though. Never the less I think you have a great design here and it would be very useful to have. Thanks for posting.

-Brett Erskine
 
Re: DIY Follow Focus

Thanks for your response Kai and Brett. Right now its only going to be dvx based. I’m poor so I don’t see my self using any other camera at the moment.

So far the main bevel gear is 2 inch in diameter and the other connecting gear is a ½ inch. The pulley will be removable so you can change the size of it. One of the things I was wondering was, how far do you have to turn a real follow focus to get from min. to infinity on the dvx.
 
Re: DIY Follow Focus

..in my fiddling with building one previously, i found that with apx a 1 inch diameter wheel/gear  you want about a 3 to 1 turnig ratio from the knob to the gear.. for one full knob turn to equal 1 full focus ring turn.. so assuming you used a 1 inch gear.. youd want apx a 4:1 ratio knob to gear for the 1/2 turn = full focus pull.. i was using an RC transmission/differential gearbox which was 3:1 ..worked really well, but never had time to really finish it.  :-/
 
Re: DIY Follow Focus

Well if you set up your ratio so that you can focus from minimum focus to infinity in a little more than a half turn of the knob this will allow you to do a full focus pull in one move rather than taking your hand off the knob and turning it again to finish the focus pull.

Now if you dont think you will ever do such a wide focus pull then set up your ratio for finer adjustments instead.
 
Re: DIY Follow Focus

Thanks guys, that’s just what I was thinking. The gears that I was thinking about using I believe will have a 4:1 ratio. My fine adjustment will come from the size of the pulley on the end.

What do ya’ll think of a pulley and a belt to connect to the lens. I am thinking a round belt that fits in the groove where the green line is on the focus ring.

Oak Ridge, damn we almost moved to Knoxville. It depended on my wife’s job. If you ever need any help or another dvx don’t be shy. A 2 hour drive would be nothing. I’m used to driving to New Orleans for work and now it will be about 7 hours.
 
Re: DIY Follow Focus

Hey M Bass I live in murfreesboro I am about an hour and a half from you. Knoxville is a bit more than a 2 hour drive from Chatt as well. I am really interested in helping you develop this follow focus but I would really like to see it work with the century ring, I don't know if I am so into the idea of belt driven, I think then it looks very DIY and also could have problems with slipping. I will be in Chattanooga on the 31st to finish up the Maal the pimp Nappy roots MV so we should get together and figure out how to make this thing work. I am totally willing to throw in what ever money is need to get this thing running as long as I get one.

If you need my number just let me know, or you can give me yours cause I have free long distance.

Ryan
 
Re: DIY Follow Focus

Well I’m sorry to say Ryan, our moving date has changed since I first posted this. I will not be moving up there until the 1st. I would like to hook up and exchange some ideas. Let me get settled and I will pm you my number when I get it hooked up and my email.

As for the follow focus I was trying come up with a cheaper way of doing it because I can’t afford the focus ring, but the pulley can be replace by anything. A friction wheel or a gear. I have a 300 page catalog on gears, I am sure we could find one that fit.

The body of follow focus is aluminum but the first one will come out looking kind of diy because it is made up with channels and angles. I can powder coat it but I don’t think its going to help much. I need to come up with a working prototype before I can start working on the aesthetics. I do have a small mill / lathe that would be good to use for the body, but I have to rebuild the table first.
 
Re: DIY Follow Focus

Sounds great, I am really into this. I really like building things so I'm sure you will probably hear more from me than you would like to. It will be nice to have another DVX user near. People are so stuck on 60i or film here, and mainly 60i its really disappointing. Just too afraid to make the leap. Take care and I will talk to you soon.

Ryan
 
Re: DIY Follow Focus

I'd definitely like to take a crack at this. I have a very well-stocked hobby place near me, so I'm pretty confident about finding the right RC parts there. Would you mind posting the part numbers and measurements, or e-mail to info@meandthewife.com? I promise to share every painful lesson I learn in the attempt. Pinky swear. :)

Aureliano
 
Re: DIY Follow Focus

I have a DVX 100A and a Sony PD 150 also.
Do yuo know a project about a remote zoom and focus controller for this camcorder.
Thank you
 
Re: DIY Follow Focus

Would it be o.k. to ask for a few measurements & scale.... just enough to be able to get the rest of it measured? BTW...I live in Nashville.
 
Re: DIY Follow Focus

[quote author=gio_589 link=board=Links;num=1090001529;start=0#14 date=07/31/04 at 23:10:05]
Do yuo know a project about a remote zoom and focus controller for this camcorder.
Thank you [/quote]

I have some friends who built an RC unit that was on 2-pop for awhile. They built it to control focus on the DVX-100 while it was mounted on an RC Helicopter for doing aerial shoots.

If you are still interested, send me a message, and I'll give you their contact information.
 
Re: DIY Follow Focus

Holy crap I am finally back, excuse the French but it’s a long ass two weeks. First off moving across states sucks and u-haul can burn in hell…

Sorry I had to get that out. Anyway to answer a few questions real quick I work kinda off the cuff so the drawing is not to scale. I start by drawing the project out to see if it will work and then I start building as close to the design as possible while making changes that I see fit. I am still unpacking so my sheet that the measurements and part # are on are temporarily lost. Sorry I am a jack ass. In my defense I did not pack my house my wife did while I was at work so something’s are randomly put into boxes.

So this is sort of out of memory if anyone is still interested:

The 2 channels are 1x1x1/2
the gears are found at hobby town usa
4:1 right angle gear used for a transmission
It was a little over 5 bucks and it was a replacement part
The main gear was 2” and the small one is a 1/2” in diameter
The actual knob I have know idea. If anyone has any ideas post it. I was thinking I would have my friend machine one, So I could use it as a mold and cast duplicates with polyester resin.
The main shaft is ¼ inch diameter
The inner shaft that is for macro can be anything that fits into the ¼ inch shaft
I’m sorry but that’s about all I remember.

To answer personal questions
Aureliano that’s all I have right now but I will pm you or post it when I find my sheet.
Hilfilootin and this goes for anyone close by if you need an extra hand drop me a line I’ll be glad to help
Gio marktek.com has a zoom/focus controller for a pd150 for 40 bucks. Its l control so it will only work with 150, but conceivably this should work for focus for both cameras.
Mjhardin do you know a link on the 2-pop forum for info?
Ryan I am sending you a pm in a few.
 
Re: DIY Follow Focus

Thanks... In the middle of moving myself, to Orlando, so I know just what you're going through. :) I have a number of DIY projects I plan to get onto once we've moved, and this plus a sunshade is right at the top.
 
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