Dan, the second link is to a restricted area.

Thanks for the info. I'll look for an identical lens.
Just one more thing about my camera (adapter), it is to big to put the second lens next to the camera's lens. This image explains the difficult setup:

http://doublecam.250free.com/viewfinder.jpg

That's why I figured a wire (flexible axis) or something would help to extend the follow focus .

You will get quite a bit of parallaxe there....
argh........fo-get-a-bout-it.... a lot of headache and you will be stuck in gears for months without consistent results....

For the set up you have, I would slide the mirror back about 17-18mm and mount a MC filter (that will act as a mirror) at 45 deg (closest to the GG) and a tiny CMOS survailance type on top to capture the image of the GG (reflected in the filter)and display it on a monitor (of your choice) You can mount the CMOS so you see it up right. They (CMOS) do not need A LOT OF LIGHT to give you an image (remember, it "steals" the image of the reflection in the filter) they are cheap (less than $20) and your camcorders will not suffer any amountable light loss or image degradation.
(this is kind of a tiny prompter or videoassist for film cameras)
You could have it up and running in no time!!!! (I guess)

Hmmm...too bad for me. But the idea of the mirror and surveillance CMOS is quite good. Thanks.

why is too bad? Are you stuck with the previous idea?Let's "grease" the mind:
Steadicam, crane, dolly. How do you frame (with what you wanted to do?) CMOS can go in a tranmitter and you can have the pic wireless......
I'll leave it with you.....

Too bad because I already made a separate viewfinder mounted on the camera. Well, I can always use it for a directors finder. I like the idea of the CMOS.

"What's so hard about a DIY Follow Focus? "

It is hard to make the gears with no backlash. Learned from experience:
http://p200.ezboard.com/fhomebuiltst...picID=29.topic

But if you find the gears ready made, of high quality...

Good show, very good job. Bravo. Gears are not hard to find (here). To have them in place without play is harder. Add two more gears in the equation (to get the reduction that you want) and... you are there. (didn't want to do it but I had no choice) One tiny problem: if another lens does not have the same outer diameter..... it will not engage or not fit....(given that FF gear relative to lens does not change/adjust) For one lens only though is PERFECT. BRAVO!!!

...

It was fun, though! :)
gears placed at 90degrees are easy to tune, but I had to leave some room for the rough teeth to move...

It is puzzling how you manage to synchronize the two small cameras with the focus ring of the lens, in you device...

I did not do it myself. A very gifted and dedicated programmer (of the same BG!!)wrote some 3000 lines of code over 5 months to "learn the motors" to respond to the lens movement (one way for one and backwards for the other...tested the distance intersection with lasers....analyzing the distance spread on many Zeiss/Cook lenses.....(long story but F U N stuff)

I thought about another existing 90° mechanism. How about a guitar tuning mechanism. Or maybe on for a contrabass or something.

http://www.qtcgears.com/e-store/DPGears.htm

Bottom left: Worms & Worm Gears, is exactly a guitar tuner.

yes......but are you changing careers?
is it not 3 or 4 more suitable for FF?
Could you rack from one end to the other of the lens in one second using the worm gear? (without a motor that is)

Dan, you'd better tell me. I was just wondering what could be used and is ready made (and not expensive)
So if you turn the first axes, the second one (after 90°) should turn in the same amount, or more?

"Dan. You’d better give me a fish and don’t teach me how to fish"....
It is all a matter of ratios.
What is the gear diameter on the lens? How much is active (out of it)?
What is the gear diameter on the engaging gear?...
In how many turns should I turn from close to >< (infinity)?
In one turn or less.
Say you have a 90mm dia on the lens and close to >< is spread on 180 deg (so, only half) Equivalent dia of the lens is? 45mm.
Now, if your engaging gear was 45 mm dia, you would need a 1:1 ratio in the miter gear. Right? But if you do not have the exact above figures, how should I know what would work to lead you to the desired result? Start with gear on the lens and the engaging gear of the FF, the rest will follow. Now you can go "fishing"....
If the two lens (filming and viewfinder) were counter rotating from close to >< you could figure two diameters that will engage with each other and keep the distance in sink (but that would be toooo much to calculate...)

Can you make that a fried fish instead?

I was just asking stupid questions find a way for many people, not only me(I have a weird setup anyway), to get the basic elements of a FF from ready made stuff. So the best thing to look for is probably a 1:1 ratio (It looks like that's what Cosmin used)
I also wonder how a professional FF deals with different lenses?

>>>>>Can you make that a fried fish instead?<<<<<
Sure can.
what would you like on the side signore? *smile* and relax, no pun intended...hey?*smile* and enjoy the ride.
>>>>I also wonder how a professional FF deals with different lenses?<<<<<
Derz an artuc.... arctic.... hmmm ... an arm... that moves in and out to reach different lens diameters.
Recent lens designs like Zeiss superspeed have the same dia at the same distance from the mount (aint that swell?)*smile* life is short.
(......hmmm....artuculite?)
Oscar, der aint no stupid questions, OK?
Is just that there are too many variables to provide a "formula" that works. I forgot to add, you should consider the distance from "rods" to lens as well. (the nightmare's just B gun) I want to make sure you understand I admire your 2 camera idea and implementation as well as all the hard work involved to make it happen. I did not make fun of you OK?
Just average, "no name" entertainment...*smile* (I like that)

Right! Make that "Dan, you’d better give me a fishing rod in stead of a fish" ...maybe I can make a FF out of it.
Many thanks for your replies, you know a lot. I'll be experimenting with this in a few days. For me, thats always the best way.

first i think that Dan Diaconu's work is amaizing , and i really wan t to try to make a FF , i have this miter gear that i think could be modified, also my rig is an fx1 with a mini35 i have the original 15mm rods of the adapter but i also made 2 long aluminum rods to support a long argeniux zoom lens, maybe i could use the argeniux arri base for the FF as well , Dan let me know what you think of the gear that i have:

http://www.reggaetonmusictv.com/mitergear/miter_gear_ruler.jpg
http://www.reggaetonmusictv.com/mitergear/miter_gear_side.jpg
http://www.reggaetonmusictv.com/mitergear/miter_gear_bottom.jpg

But I ain't got no fishing rods nor fish here (somthg's fishy though) ....always good for a laugh.... thanks guys. almost 4goat : *smile*
Now:
I'd still go with the CMOS thing (in your shoes) and a FF for one lens only. You'll make it somehow, I know.
Rafael, all you may need is da right (or the left?) gear to go on the lens (instead of the one mounted now) or you could engage that one to another one to go on the lens and you're there. What you have for 15mm rods might be the best thing you need to mount it. Good luck.

Has anyone considered a "strap on gear" for the lens ring?... something similar to a zip-tie but with larger teeth? I don't even know if they make them but it'd definitely be worth looking into. Just standardize the teeth, and then you can build an any-camera follow focus without having to worry about the lens ring.

great, thanks Dan, also i have canon ef and nikon still lenses to use with the mini35. is it better to fix some kind of gear ring to them? are this rings comercially available? what could i use for it ? what about plastic ones?

You can order these rings from the manufacturers of pre-existing products, but the rings sell for between 100-200 dollars. Plus, if add on a micro35 or any lens for that matter, the ring becomes useless and you have to buy another one to fit that specific lens. I would much rather have a disposable/adjustable strap to save me from that problem

Rafael,
the Nikons I have mod have four different dia (out of seven lens) so, I had to do custom fitting rings. However, the outer dia I made is the same for all. A pain, but awesome to work with now. I also had to take them apart (one by one) and re-do the greasing job which was good for still lens but not adequate for "in take" focus roll speed (they were stiff)
Now, they have the Zeiss moves....hehehe....
Same for a FF I played with today. Made in China, sold here for $ Can 1200 (about US$950) Stiff (well... compared to the one I made and the standard) and therefore solicitting in use. (small "details" that add up when one looks at a certain product and questions the price like I do) There were other two inconveniences but I would prefer to move on and follow Shannon's advice and make one (the way I would like to use it) available for a decent price that will address those issues as well. Working on it....

<<<-- Originally posted by Daniel Skubal : Has anyone considered a "strap on gear" for the lens ring?... something similar to a zip-tie but with larger teeth? I don't even know if they make them but it'd definitely be worth looking into. Just standardize the teeth, and then you can build an any-camera follow focus without having to worry about the lens ring. -->>>

What about nylon or thin plastic rack (& pinion) gears? Do you think you could get one flexible enough that you can just bend it around the lens and you could either glue it or screw it in place? If there was anything like this, then you could probably make it into something that can be strapped onto any lens, like daniel's saying, but i'd think it would need some hella grip to keep from slipping around.

<<<-- Originally posted by Matt Kelly : <<<-- Originally posted by Daniel Skubal : Has anyone considered a "strap on gear" for the lens ring?... something similar to a zip-tie but with larger teeth? I don't even know if they make them but it'd definitely be worth looking into. Just standardize the teeth, and then you can build an any-camera follow focus without having to worry about the lens ring. -->>>

What about nylon or thin plastic rack (& pinion) gears? Do you think you could get one flexible enough that you can just bend it around the lens and you could either glue it or screw it in place? If there was anything like this, then you could probably make it into something that can be strapped onto any lens, like daniel's saying, but i'd think it would need some hella grip to keep from slipping around. -->>>

Do they make gears like that? For most lenses, the built-in focus ring is rubber, so if you could just make a locking mechanism like a watch (where it folds back and clips in), or maybe even just a pin system...

I'm no engineer but I believe standardizing the gear strap and making it adjustable would be optimal for making a DIY FF

Also, the gear strip wouldn't be required to go all the way around because most focus systems only have a 120-270 degree turn radius, so as long as the strap device was opposite to the ff gear, there would be no confrontation.

This is the sort of thing i was thinking about http://www.machined-plastic.com/rack.htm The green gear isn't the best example, but i bet something similar to it could work.

Ohh! Yeah I think that would work... that was actually what I was "looking" for when I originally posted the idea. Hmm... I think this may be something worth pursuing. I mean... a 1$ piece of plastic versus a 350$ crafted product... I think it's worth a try.

Well if you want to try it, go for it. I'm definitely going to try my hand at building a set of rails for a follow focus, but at the moment i'm working on a mini35 adapter first... so it'll probably be weeks before i plan out measurements and gear ratios for the follow focus. Lemme know if you have any progress.

Also... any tips on making a follow focus? I've seen some homemade ones involving miter gears, but i have no idea if they work anything like the real thing. i.e., one hand turn of the follow focus should pretty much give you full range of focus turn on the lens. don't know much about gearing either, other than what i've done with legos. :)

<<I also had to take them apart (one by one) and re-do the greasing job which was good for still lens but not adequate for "in take" focus roll speed (they were stiff)>>>

Dan, is any normal grease fast enough for an FF. I wonder if it is grease in (slow) lenses. I searched a long time for the right grease to redo my arri tripod head. When I put sticky resin instead of grease, it gave exactly the slow moves it needs. Is it resin they put in there originally?

The "ideal" FF (as well as the "blamed" as expensive ones) should not have any more friction than required in the bearings (not much) The Cavision that I have looked at was stiff (when compared to "normal") That alone (aside from stiff lens) can make the difference between being "soft" or slow to reach focus and "right on" during a "fight scene" or fast moving objects in and out (towards and away) from the lens.
The resin in the head is OK (for a while) as the closest to original.
In the lens, there is "normal grease" for the job they were meant to do. However, that makes them "slow" compared to the way the cine lens turn.
I had to clean them all with WD40 and replace it with some stuff I saved from other mechanisms I had worked with. I am sure there is commercially available somewhere, but I did not need, so I do not know. End result is what matters and they turn EASY.

Hi Everyone,

I am adding to this post to inform you Redrock Micro (the micro35) is intending to build a low-cost, high quality follow focus.

We are soliciting input from you on what you want in this product. We have already started a thread on input that can be found here:

http://redrockmicro.com/forum/viewforum.php?f=15

We hope you will visit and tell us what you want. Redrock's intention is to offer this to digital filmmakers everywhere with the philosophy of high quality products at revolutionary prices. Those of you who are familiar with the (soon to be released) micro35 can fully appreciate what this means.

Thanks

Brian

Most of the problem comes to the fact that most people of here don't know how to machine. So they have to take their design ideas to someone and let them create it. Machinist charge, I'm sure, alot. I don't know exactly, but I'd guess at least $60/hour.

Fortunately for myself, I've got many years experience in machining. This past week I've been buying metal and various other things to do a few projects, one of them a 35mm adapter. Another one is a rail system - no big deal there. Another is a matte box with barn doors and a filter holder. Another is a follow focus and yesterday I picked up 50 bright white LEDs (at 15000 mcd a piece) to make one of those LED cam-lights....kinda like the light rings that are made now.

I was surprised at what aluminum costs. My first outting I picked up some at a scrap yard for kinda cheap. About $0.70 a pound. Two days ago I picked up some for $0.35 a pound and I'm going back for more. Also picked up some stainless rod, 1/2" dia., for $1 a pound. So far I've spent under $20 for material and I've got enough to do most of these projects. Now I just have to sit down, plan, and start machining.

Like I said, lucky for me I know how to do all this stuff. But if you were to pay someone to machine it for you, I can see very quickly how the price skyrockets in no time flat.

Court

These are a couple of pix of the follow-focus rig that we made up for the FX1.
It uses a "strap" gear mounted on a specially machined alloy holder.
The right-angle gear drive was purchased from Maplin UK for only 17 GBP!!!

http://img.photobucket.com/albums/v1...llowfocus1.jpg

http://img.photobucket.com/albums/v1...llowfocus2.jpg

Robin

Oh wow! How is the motion on it? Pretty smooth? What about the strap gear? Where'd you find that at?

All-in-all, how much did the ff cost? I assume the machined alloy drove the cost up quite a bit

The motion is very very smooth - and makes finding focus a breeze. Especially as you can set up a mark and return to it (which after all is the point of the rig...)
It only really cost me 18GBP and a few bottles of wine, since I had it made up by a pal in the BBC mechanical workshops here in Cardiff. He takes a real delight in making up bits of gear like this. My next project is to try and interest him in a mini-35 adaptor .... ;-)


Robin

Very cool! Any chance you could post your design? I'm sure others would be quite interested.

Aaron,
I'll do my best.
There weren't any real drawn-up plans, merely a case of adapting bits and pieces that were available to us.
The hardest bit (at least, I thought it would be..) was to find the right-angle gear drive. I did a Google search and came up with : THIS

Once we had that, it was just a case of mounting it to the 15mm rods that I already had for the Arri matte box. We found a spare slider for the rods and machined a block to hold the gearbox, with slots to allow the gears to be moved up to the lens gear ring as required.
I'll take some more pix as soon as I get a chance to show the parts in more detail.
I'm very happy with it and have already been using it on some docs that I'm shooting for the BBC as well as for one of our commercial channels.

Robin.

Awesome :). I know how building things goes so no worries!