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Old February 24th, 2004, 07:10 PM   #1
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Any ideas for a homemade focus puller...

to work with a one touch SLR zoom lens and primes

without drilling and tapping holes into the lens

this is a tough call sorry :)
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Old February 24th, 2004, 10:11 PM   #2
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One Touch is a Canon pro lens?

If so, the focus puller can easily be mounted. Just have to build one that fits which isn't all that difficult a trick. Just have to have a machine shop. :-)))

You want a moving arm or knob? Fine control or fast speed?

I'm asking questions without having any idea of a commercially available solution but with a machine shop sitting 10 feet away.
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Old February 24th, 2004, 10:38 PM   #3
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OK guys, no laughing, just hear me out.

Many years ago, while working in the Camera Department of CineVideoTech in Miami, the owner, Egon Stephan,gave all of his guys a gadget that he then began selling to camera assistants.

It worked on the same concept of an oil filter wrench and opened far enough to slip over the zoom or focus barrel of the Angenieux and Cooke 5-1 and 10-1 lenses. You would then turn the knob at the bottom to close the loop and make it snug against the barrel and, PRESTO...you had a manual zoom/focus handle.
Much to my chagrin, years later I saw this same gadget in a kitchen store. It seems that it was originally made, and continues to be made by Zyliss, a Swiss company that specializes in some very cool kitchen stuff!

I have always carried a couple in my ditty bag and have one in the kitchen as well.

You can still find them at: http://www.zyliss.com/

Go to the search box and type in "strongboy".

By the way, the blue "half moon" you see at the end of the opener is used to keep the band straight during storage, thus avoiding any kinks in the band.

RB
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Old February 25th, 2004, 12:58 AM   #4
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Somehow the handle needs a counterbalance. At least on my lens, the weight of the handle would cause it to move the focus or zoom sleeves.
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Old February 25th, 2004, 01:49 AM   #5
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so get two
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Old February 25th, 2004, 08:41 AM   #6
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Thanks for the suggestion on the gizmo, Rick. Seems they are being sold off Amazon for about 13 bucks but I'm sure someone else on the web is selling them for less.


MIKE: Since you mentioned you've got a machine shop aching to be used for this sort of thing, what's the possibilities of a follow focus unit for the XL1S?

I've actually seen that a lot of the follow focus units around seem to be a stock unit with a camera specific ring.
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Old February 25th, 2004, 10:54 AM   #7
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I've thought of building a couple for my cameras. But one thing has always held me back. It can be done better electronically with servo-based lens.

For example. My PD150 has a focus and a zoom ring that are both just electronic inputs to the servo system. So a mechanical drive from my fingers to the ring is going to be a grossly inexact tool as we all know.

OK, but we know how to model servo systems. So a decent servo engineer can map out the servo system responses to ring motion, velocity, duration, acceleration so as to predict lens response to any physical input.

Once that is done, it would then be possible to program a stepper-drive system to move the rings the right amount to hit multiple focus marks, zoom between two settings (equal to Canon's Shuttle Zoom) and change focus while zooming. Even lock focus and zoom to dolly motion.

BTW, I wouldn't use clamp rings to grab onto the focus and zoom controls, I'd use a soft toothed belt drive. Shouldn't put too much side force on the lens and will be more universal (i.e. cheaper).

John, two won't work if you have a pro camera and the viewfinder is in the way. Or something like a PD150 and the microphone is mounted over the lens. A small counterweight is a more elegant solution.
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Old February 25th, 2004, 01:10 PM   #8
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Well, Mike I'll apply to go back to school for engineering... :)

'Fraid for me that is the option for a couple of years from now....

Today I need to be able to get one for my XL1S and would love a more refined method then the one I'm using now which is marking the lens and the focus ring with a wax pencil for the points of focus and having an assistant stand beside the DP and turn it manually.

I'd love a dial.

If you are in the mood to build one I know I'd buy one but I've also got a contact or two in some supply houses that I know would be VERY interested as well.
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Old February 25th, 2004, 01:46 PM   #9
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More refined Kevin?

That's how proper focus is pulled today regardless of whether you are shooting film or HD.

If you are using a manual lens and can actually hire a skilled focus puller, going to any other system would be like putting your foot through a Rembrandt!

If what you are looking for is a support system with a follow focus assembly, take a look at the Chrosziel pricelist. The best stuff in the business although not the cheapest. Probably cheaper and easier than re-engineering the thing.

http://www.chrosziel.com/ACPL09_03.pdf

Hey Mike, if we ever get stuck on Gilligan's Island, I can be Gilligan and you can be the Professor! :)

Keep it sharp!

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P.S. I've got dibs on MaryAnne!
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Old February 25th, 2004, 02:45 PM   #10
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Oh hell no. I want to be one of the sharks!

Actually, from what I can tell, Hollywood's focus pullers, at least on difficult shots are computers.

I'd bet that in 10 years, except for the simplest of locked-down shots, the pedestal and camera and all its functions will all be located at an IP address. WiFi'd. The DP/CO will sit in a trailer somewhere very much like the control rooms on wheels we see now for video.

As soon as I get this training video on Lathes completed, maybe I'll see what I can do. I think the mechanism can be very simple and yet lose no functionality. Want a dial to move, eh?
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Old February 25th, 2004, 10:05 PM   #11
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Mike,

I pulled focus for 20 years on feature films, TV shows, music videos and hundreds of commercials and I can tell you this...the focus is pulled by the first camera assistant and not a computer. My specialty, besides pulling on SteadiCam, was long lenses, wide open, and following actors that couldn't hit their marks!

The only time a computer was used to pull focus was when the shot was done with a motion control rig that had to replicate the shot time and time again with absolutley no variations.


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Old February 26th, 2004, 07:42 AM   #12
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I've looked MANY times at their stuff, Rick but the cash just isn't there.

Maybe I can sneak it into a budget in the not too distant future but not for now and I (like a lot of people) would love to find a lower cost option.


Pulling focus is a thankless job except to the people who've tried it on a moving camera.... and those of us that have are always amazed at the people who do it well.
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Old February 26th, 2004, 04:07 PM   #13
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Im glad to see there is interest on this topic

My quest is for a focus puller to work with SLR one touch zooms and primes in connection with a device like a P+S Mini 35.

The zoom is the most difficult case and I have some pictures for comment here..

http://img.villagephotos.com/p/2004-1/612657/pull1.jpg

http://img.villagephotos.com/p/2004-1/612657/pull2.jpg

http://img.villagephotos.com/p/2004-1/612657/pull3.jpg

http://img.villagephotos.com/p/2004-1/612657/pull4.jpg

http://img.villagephotos.com/p/2004-1/612657/pull5.jpg


the legend is as follows

A is a laser pointer

B is a perspex dial

C is a counterweight

D is a collar

E is a lever/strut


A brief summary is that a focus pull is achieved by activating the laser pointer and moving it as a lever in accordance with the readings on the dial


I havent worked out the precise engineering on how it is assembled, but the chief aspects are

A is a cheap keyring bullet type laser pointer avaiable for a few $, they feature an on/off button on the side

B is a perspex calibrated distance dial which looks like it will fit just after the aperture ring using a snap on circlip action

the counterweight C is necessary to back off the laser weight

D is an aluminium collar (probably in two haves and assembed on the focus ring using hidden countersunk screws)

the struts E screw into the collar

the attachment A-E will be worked out when the exact laser pointer type is known


Your thoughts are welcome
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Old February 26th, 2004, 04:54 PM   #14
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Hey John, you're over your limit at that URL, can't access the pics.

Hell yeah, there's a lot of interest in this sort of thing. Like I said above, I know someone at a major equipment house that would love to buy some inexpensive follow focus units for XL1's to resell or rent.

The ones from chrosziel just don't fit into the low/no budget indy film market.
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Old February 26th, 2004, 05:27 PM   #15
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check ebay, I saw several in the $150-$2500 zone :)
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