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Why hasn't this been invented?


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#1 Mariano Nante

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Posted 17 February 2007 - 10:35 PM

Thinking about the very difficult task of focus pulling, I came up with this idea. It's very simple, but I've never heard of anything like it, so I was wondering if there were some inherent unsolvable technical problems to it -or if indeed it already exists.

You put a tracking sensor on the actor -a tiny chip would suffize, I guess- and a receiver on the tip of the lens, measuring the distance automatically. A device similar to a follow focus would be enough to do the rest.

Now, it seems to me that the necessary technology is available, and I also think it would be very useful, considering the nightmare that wide-open focus pulling is.

So, can you tell me what you think?

Sorry if I'm being a bit naïf here ;)
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#2 David Mullen ASC

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Posted 17 February 2007 - 10:51 PM

Usually critical focus meaning following focus on the actor's eyes, so what if the chip were on their chest but the actor leaned their head forward? What if they momentarily lifted a newspaper and blocked the chip -- do you want the lens to focus on the newspaper? Or worse, what if someone wipes through the foreground of the shot? Is this a radio signal not affected by line-of-sight being blocked?
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#3 Dory Breaux DP

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Posted 17 February 2007 - 11:01 PM

That is a very good idea! I myself HATE focous pulling.. pain in the ass with high speed subjects.

David-
I'm sure there could be a way figured out to componsate for the location of the chip and have a manual override for focous. Also, I think if the unit used WiFi or something similar it wouldnt be affected by anything inbetween the receiver and the unit.
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#4 Alessandro Malfatti

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Posted 17 February 2007 - 11:26 PM

Dory's right, sure for shots in which we have a closeup of the eyes the distance would have to be set manually, but for most shots the chip idea would be great, I mean in most shots, if it's the actor you want to get in focus then it would be sufficient to have the chip around his chest. Sweet idea, make a prototype and get rich, lol ;)
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#5 David Mullen ASC

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Posted 17 February 2007 - 11:37 PM

If the focus is not critical enough to see the difference between the focus being on the actor's eyes versus their body in general, it's not all that hard just to pull focus the old-fashioned way. You don't need special technology to follow focus on such a shot, except maybe rare cases (like someone running towards the camera on a telephoto lens.) And there are already devices on the market for those types of shots.

It's when you can clearly see whether the eyes are in focus or not as an actor moves, like in a tight shot at a wide aperture, that focus-pulling is very hard.

To be valuable, an automatic focus system has to be able to track and follow an actor's eyes.
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#6 Michael Nash

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Posted 18 February 2007 - 12:03 AM

Not to mention the probable time delay with such a system. A good focus puller can often anticipate an actor's movements and be ready to adjust; and electronic system would always have a delay, however small.

Of course all this sidesteps the artistic application of focus pulling, so such a device would have limited use anyway.
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#7 Daniel Smith

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Posted 18 February 2007 - 12:11 AM

I'm either over estimating how difficult focus pulling is or I'm seeing it as something I could never do.

I mean, you would have to know the lens BACKWARDS. You would have to be incredibly skilled in managing to judge the distance and alter the focus to match it and on top of that the operator might be moving the camera.

I've tried walking around the house with my 35mm SLR and practicing some focus pulling. It was just ridiculously hard.

I'm hopefully going to be on set in a few weeks time where they will be using a mini35 adapter with a focus puller, good opportunity to ask one then I suppose.

Do you think it would be beneficial for someone like me to start practicing focus pulling at this stage?

Edited by Daniel Ashley-Smith, 18 February 2007 - 12:13 AM.

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#8 Phil Rhodes

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Posted 18 February 2007 - 12:34 AM

Hi,

I've often thought it ought to be possible to have a touchscreen with the tap image whereby you could keep your finger on the spot you wanted to be in focus, and it would automatically scan the scene and determine the distance at that point. That could certainly be done, probably with either ultrasound or a scanning infra-red setup. You'd have to have damping and dual-touch options with variable integration to do smooth pulls, but it could most certainly be done. I'm surprised it hasn't been, to be honest.

Phil
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#9 Michael Nash

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Posted 18 February 2007 - 12:36 AM

Do you think it would be beneficial for someone like me to start practicing focus pulling at this stage?


If you're a student, it benefits you to learn as much as you can about as much as can. That doesn't mean you have to become an expert in each thing, but it will broaden your understanding. And there's nothing like hands-on practice.
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#10 James Steven Beverly

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Posted 18 February 2007 - 02:24 AM

Thinking about the very difficult task of focus pulling, I came up with this idea. It's very simple, but I've never heard of anything like it, so I was wondering if there were some inherent unsolvable technical problems to it -or if indeed it already exists.

You put a tracking sensor on the actor -a tiny chip would suffize, I guess- and a receiver on the tip of the lens, measuring the distance automatically. A device similar to a follow focus would be enough to do the rest.

Now, it seems to me that the necessary technology is available, and I also think it would be very useful, considering the nightmare that wide-open focus pulling is.

So, can you tell me what you think?

Sorry if I'm being a bit naïf here ;)


They have something like that for video, It's called an auto focus, maybe you've heard of it? You point the camera at something and it focus' for you? My mom has a camera that does that for her. There's a reason for the 1st A/C guys. B)

Edited by James Steven Beverly, 18 February 2007 - 02:25 AM.

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#11 Daniel Smith

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Posted 18 February 2007 - 03:27 AM

They have something like that for video, It's called an auto focus, maybe you've heard of it? You point the camera at something and it focus' for you? My mom has a camera that does that for her. There's a reason for the 1st A/C guys. B)

No I think I'd prefer an electronic device. More accurate, responsive, reliable, small and out of the way.
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#12 Chris_Burket

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Posted 18 February 2007 - 03:44 AM

Another thing to think about is that focus isn't determined by the position of a certain actor a great deal of the time. Sometimes you pull focus from one character to another, sometimes from a character to an object, sometimes from the lips of a character to their eyes, sometimes you split focus between two people to keep both of them in focus, etc.... the list goes on. Sometimes a tool that could tell the focus puller exactly how far away an actor's eyes are would be helpful. They have the cine tape, pana tape, and sniper unit for this, but having a sensor would be another way to go.
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#13 Evan Winter

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Posted 18 February 2007 - 03:57 AM

about focusing on the eyes

1. use a wifi chip
2. place it in the actor's hair at the same depth as their eyes (i know, i know, what about bald actors - in that case they get to wear the chip behind their ears and the camera system will obviously have the capacity to recalibrate the distance to a specified '+' or '-' amount).
3. make it a system that can accomodate several chips. for multi-focus scenes the 1st simply places the chips around the space at the closest equivalent depth to where focus is desired.
4. the 1st holds a numbered keypad controller. the numbers correspond to the chips placed in the scene.

i.e. - rack to the eyes (press '1'), rack to the murderer coming round the corner behind the hero (press '2'), stay on the murderer as she walks closer to camera (just stay on two - she has the chip in her hair or behind her ear), rack to the gun on the table in the extreme foreground that the hero is discreetly reaching for (press '3').

i believe the technology to build all this stuff exists...it may be too expensive to manufacture for the short runs required to meet demand in the film industry though.

just my .02
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#14 K Borowski

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Posted 18 February 2007 - 04:23 AM

No I think I'd prefer an electronic device. More accurate, responsive, reliable, small and out of the way.


I agree, focusing a camera and keeping the focus sharp continually without noticeable breathing or correction is something that may be beyond the capabilities of a good many to master. It's just like color timing, I have gotten better at it now that I've been doing it for about a year professionally, but there are people that can tell me in seconds that I have a color cast on a picture I've printed and how to correct it. They're just that good, to the point that I am either incapable of becoming or, frankly, not willing to devote the extreme amount of time that would be necessary to master it taht well, which would in all likelihood mean I'd have to drop out of college in order to have that sort of time.

Daniel, by virtue of the fact that men make machines, there'd be all sorts of anticipated problems they'd work out and unanticpated ones that would plague the first few generations of hte devices until they got it right. Remember, *engineers*, not filmmakers are the ones that design this equipment. They have I'm sure some experiences with focus pulling, or are at least instructed by someone that has, but that can easily mean they are no more skilled at it than you are, or I am (not very much at all, we'd probably ruin shots if we were racking focus on the sets of a major motion picture). Do you really think machines designed by those that are, at best amateurs at doing focus pulling themselves will be easily able to emulate the skill of a human being who takes countless hours of practicing and oftne has an inate gift for this sort of thing, as I will certainly never be able to ask a director "Mr. Kubrick, *which* eyeball do you want in sharp focus during the shot?", and easily build a machine that will put said skilled worker out of the job? I think a crude device can be manufactured that would allow for rudimentally racks and follow focus, but I don't think you'll have any F0.7 automated focus units anytime soon. Remember, that in stilll photography, without the visible red autofocus light, autofocus systems are actually still less able to focus in dim light than the human eye. . .
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#15 Dino Giammattei

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Posted 18 February 2007 - 07:41 AM

From the half serious, answer department:
With the way cosmetic surgery has almost become a requirement for an extended acting career, how much more trouble would it be to start implanting multiple micro devices under the skin. Perhaps a couple right between the actors eyes, and a few others at different places on the body. It would work like a tollbooth sensor. When excited by the cameras transmitter, the sensors would reflect a signal back to the focusing computer, running some fuzzy logic program. The software would not only extrapolate the distance, but also the position of the sensors, relative to the camera, and most importantly, to each other. That way, the movement of the actors head and body would be automatically compensated for.
Now if we could implant something that would help them remember their lines, and work for peanuts, that would be something!

It's my birthday, I can be silly if I want...
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#16 Stephen Williams

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Posted 18 February 2007 - 09:00 AM

about focusing on the eyes

2. place it in the actor's hair at the same depth as their eyes (i know, i know, what about bald actors - in that


Hi Evan,

So what happens when you shoot in profile?

IMHO if it was that easy it would have been invented years ago. It's a bit like why drive your own car when you can sit on a train!

Stephen
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#17 Rory Hanrahan

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Posted 18 February 2007 - 10:13 AM

You guys are creating the Rube Goldberg method of focus pulling!

Why doesn't the signal bounce to a decomissioned NASA satellite, then relay to a secret bunker in Munich, then be sent by bike courier to the studio, then the 2nd AC can bring you a wax-sealed envelope, then you can open it (finally feeling like you're on-stage for the Academy Awards) and finally, nudge the dial the half-inch necessary to find your subject.

I swear to God in twenty years we'll all be replaced by robots.

And in conclusion, the answer to your question (which was, I believe, "Why don't we use automatic follow focus?")...


Robots don't pay union dues.
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#18 Sam Wells

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Posted 18 February 2007 - 10:25 AM

Not to mention the probable time delay with such a system. A good focus puller can often anticipate an actor's movements and be ready to adjust; and electronic system would always have a delay, however small.

Of course all this sidesteps the artistic application of focus pulling, so such a device would have limited use anyway.


Yes, for instance I've always thought the term "follow focus" was an unfortunate one, if you're following you're late :D

-Sam
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#19 Hans Engstrom

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Posted 18 February 2007 - 11:09 AM

Being a good focuspuller is about practising. When pulling focus every day and doing it on handheld/steadicam you get very accurate on judging distances. The hardest thing I ever done is when pulling focus for someone you haven´t worked with before and they are VERY active with the handcamera. After a while you learn to anticipate their movements and everything gets easier but in the beginning it constantly feels like you´re late. When I´m operating (not very often but it happens) I like being able to have a dialogue with the focuspuller and wouldn´t like to have them replaced by some gadget. A focuspuller can tell me if the take was good for them or not, I can tell them what I´m planning to do so that I´ll make it easier on them. I really don´t see anything good in trying to change the way it´s done today, it works better then any automatic system would ever do. I can´t see myself whispering to a autofocus device "put the focus on his hand..."
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#20 Michael Nash

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Posted 18 February 2007 - 04:40 PM

Focus pulling is kinda like surfing; you're responding to the wave, but you're still in control of what you do, and can be very expressive with it. And it takes great control and experience to make it go the way you want!

No matter how fast or precise we could make a machine that pulls focus, it would never replace the "performance" of a human being (especially when that peformance is interacting with human actors). It's just not the same thing.
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