Jump to content



Photo

Acceleration vs. constant movement


  • Please log in to reply
48 replies to this topic

#1 Alan Dague-Greene

Alan Dague-Greene

    Advanced Member

  • Sustaining Members
  • 48 posts
  • Denver, Colorado

Posted 05 March 2008 - 10:33 PM

Let's see if we can't mix a bit of special relativity into the Steadicam stew.

I was just watching a shot that was a simple pan across a landscape. The pan was executed with such unwavering, mechanical precision that?small movements in the distance aside?it may as well have been a scan across a still photo. And I got to thinking:

In Steadicam, is a moving shot that is completely devoid of acceleration the same as a non-moving shot?

Take the most basic situation: following a subject down a hallway, at a fixed distance and a fixed speed. No starts or stops, no panning or tilting, as these are all forms of acceleration. The closest example I can think of is this scene from Philadelphia on Steadishots. Movement on a curved line qualifies as acceleration, so it's not quite the perfect example, but it's darn close.

Einstein's theory of special relativity says (in grossly simplified terms) that an observer who is in motion but not accelerating, or who does not perceive themselves to be accelerating, may observe their surroundings as though they themselves were standing still.

If we, as the observers, experience no sensation of acceleration with respect to the subject of the frame, then the world outside of that subject (the background) appears to be the thing in motion. The hallway appears to be sliding by us, rather than us moving through the hallway.

Of course, this is all theoretical, as no human operator could achieve absolute mechanical precision, if such a thing were even desirable. But it has me thinking, and many questions of varying ludicrousness come up:
  • At what point does a shot feel like it's moving?
  • Could many Steadicam shots be described in this way, as a series of constant, "fixed" segments connected by moments of acceleration?
  • Does acceleration break the observer out of a static frame of reference permanently, or would a return to constant relative motion invite the sensation of standing still to also return?
  • To what degree does the pursuit of making the frame "invisible" require the operator and subjects to entertain this idea of acceleration-free movement?
  • Which is better, Glidecam or Steadicam?
  • Should I take a workshop?
  • Meatloaf again?

  • 0

#2 Rob Vuona SOC

Rob Vuona SOC

    Advanced Member

  • Sustaining Members
  • 1143 posts
  • Los Angeles

Posted 06 March 2008 - 12:18 AM

Let's see if we can't mix a bit of special relativity into the Steadicam stew.

I was just watching a shot that was a simple pan across a landscape. The pan was executed with such unwavering, mechanical precision that?small movements in the distance aside?it may as well have been a scan across a still photo. And I got to thinking:

In Steadicam, is a moving shot that is completely devoid of acceleration the same as a non-moving shot?

Take the most basic situation: following a subject down a hallway, at a fixed distance and a fixed speed. No starts or stops, no panning or tilting, as these are all forms of acceleration. The closest example I can think of is this scene from Philadelphia on Steadishots. Movement on a curved line qualifies as acceleration, so it's not quite the perfect example, but it's darn close.

Einstein's theory of special relativity says (in grossly simplified terms) that an observer who is in motion but not accelerating, or who does not perceive themselves to be accelerating, may observe their surroundings as though they themselves were standing still.

If we, as the observers, experience no sensation of acceleration with respect to the subject of the frame, then the world outside of that subject (the background) appears to be the thing in motion. The hallway appears to be sliding by us, rather than us moving through the hallway.

Of course, this is all theoretical, as no human operator could achieve absolute mechanical precision, if such a thing were even desirable. But it has me thinking, and many questions of varying ludicrousness come up:

  • At what point does a shot feel like it's moving?
  • Could many Steadicam shots be described in this way, as a series of constant, "fixed" segments connected by moments of acceleration?
  • Does acceleration break the observer out of a static frame of reference permanently, or would a return to constant relative motion invite the sensation of standing still to also return?
  • To what degree does the pursuit of making the frame "invisible" require the operator and subjects to entertain this idea of acceleration-free movement?
  • Which is better, Glidecam or Steadicam?
  • Should I take a workshop?
  • Meatloaf again?



Alan,
Did you cough after that bong hit . . . .LOL . . . .

Yes of course it's meatloaf again . . . .Da !
  • 1

#3 Robert Starling SOC

Robert Starling SOC

    Advanced Member

  • Sustaining Members
  • 1134 posts
  • Las Vegas, NV

Posted 06 March 2008 - 01:07 AM

Did you cough after that bong hit . . . .LOL . . . .


Jeez Rob, I was thinking the same flippin' thing but I think he was chasing it with tequila.. those little worms will get you "thinkin". That has to be one of the best one-liners I've ever read on any forum!
  • 0

#4 Matteo Quagliano

Matteo Quagliano

    Advanced Member

  • Sustaining Members
  • 423 posts

Posted 06 March 2008 - 04:45 AM

Don't understand quite nothing about Alan questions... but the shot he linked is great, expecially because they're ascending and the camera is little tilted down (in my guess) giving the impression they're like folling down ahead when walking... I really like it...

Matteo
  • 0

#5 chris fawcett

chris fawcett

    Advanced Member

  • Sustaining Members
  • 1016 posts
  • Europe

Posted 07 March 2008 - 05:31 AM

Wow Alan,

Love the funky post.

If we operate at relativistic velocities (I myself have yet to come close to c, or even 99.99% of it), our first worry might be the mass of the sled increasing towards infinity, or perhaps the time dilation problem, where a few seconds for us would appear to be several centuries for the rest of the crew (something that crews regularly subjectively experience anyway). Less worrying would be our dimension in the direction of travel decreasing towards zero?very handy for dodging through doorways.

Since we operate within a demonstrably Newtonian universal subsystem, I'd be happy just to invoke the 1st law of motion: Every body perseveres in its state of being at rest or of moving uniformly straight forward, except insofar as it is compelled to change its state by force impressed.

This allows us to consider the operator, within the Newtonian paradigm, as simply occupying a series of Lagrange points throughout a multi-body system, where the operator has negligible comparable mass. Navigating the narrative space between these points being achieved by engaging in a number of Hohmann transfer maneuvers to obtain increasing and decreasing orbit potentials?without violating the first law of thermodynamics, and maintaining delta v?relative to the competing narrative potentials?as close as possible to zero, obviously.

Pass the bong,

Chris
  • 1

#6 Charles Papert

Charles Papert

    Advanced Member

  • Sustaining Members
  • 2224 posts
  • Los Angeles

Posted 07 March 2008 - 09:27 AM

where the operator has negligible comparable mass.


Yeah, but then craft service brings around the fresh-baked chocolate chip cookies, and this theory quickly falls apart.
  • 0

#7 Alfeo Dixon SOC

Alfeo Dixon SOC

    Advanced Member

  • Sustaining Members
  • 756 posts
  • Atlanta

Posted 07 March 2008 - 10:28 AM

Ssshpt, ssshpt...

Alan, in theory yes. But the reality of what the view experiences no. We move the camera with purpose, steadicam allows to viewer to experience a space intimately with an actor. The way we are taught to operate is to move with and when the actor moves, keeping the exact speed and distance of the subject. This movement allows for a transparent experience. The key is experience. What the view will experience.

In regards to the shot in Philadelphia, yes without acceleration this shot could have been a static shot and would convey the exact same message off the pages of the script. But, would the view experience the same feelings from the two shots? No. The following question of the experience is...

Static: where are they?
Steadicam: where are they going and where did they come from?

Even more relative to your question of acceleration. What would be the impact of that scene if the four men accelerated faster than the camera and drifted further and further away from the camera vs. the opposite and we (viewer/camera) start at a distance and accelerate to catch up with them. Three totally different experiences.

The cool thing about movement is that we do experience movement. A long straight highway in the middle of the desert, for example. If we look out to the horizon, the vanishing point of this highway is the same. It's still along fcuking way off to no where. Now we have the setting, but how do we tell the story... Static shot of a man standing in the middle of the highway and we experience that its going to be awhile before he gets to anywhere. Steadicam of this man walking in the middle of the highway... same experience, but at least he's now on his way.

ahhhhhh, :cough:

-Alfeo "I'll pass... Chris, just say no"

BTW: http://video.aol.com...layer/997951900
  • 0

#8 Brad Grimmett

Brad Grimmett

    Advanced Member

  • Sustaining Members
  • 718 posts

Posted 08 March 2008 - 04:12 AM

I think I understand what Alan is saying. He's talking about doing a moving shot at an exact constant speed without acceleration and having the perception that the world is moving around the people instead of the people moving around the world. I've experienced this while walking before. It's a strange feeling. The feeling is kind of relative to un-focusing your eyes and looking at one of those out of focus pictures until it comes into focus (remember those?). You feel a little out of your own body. And no, I wasn't smoking anything at the time.
It's an interesting thought, but I think it would be very hard to achieve with steadicam since the actor(s) need to be at the exact same constant speed and motion as the operator. Also, I don't know that you can achieve that feeling through a lens. I just wrapped about an hour ago, and the last shot of the day was a girl mounted at one end of a dolly and myself and the lens at the other. We travel down a hallway as she is firing guns with both hands. This setup is more likely to replicate this particular feel than steadicam I think, because our speed is exactly the same and the world is moving by us at exactly the same pace. There is an odd feeling to the camera's speed being linked exactly to the actor, and it's a different feel than steadicam. With this type of shot the acceleration is in the hands of the dolly grip, and for this shot I just did, there was acceleration coming from the dolly, wanted or not. With no acceleration we may have come close to what Alan is talking about, although I don't know if it would have been perceptible or not through the lens.
In the end, I don't think this is what we're looking for with steadicam (whether we can do it or not), because the feel and effectiveness of steadicam depends on the fact that things in the frame are moving independently. If every moving object in the frame was moving exactly with the steadicam the feel and effect would be very different.
I'm having trouble wording what I'm thinking, but I hope you all get the idea.
  • 0

#9 Imran Naqvi

Imran Naqvi

    Advanced Member

  • Sustaining Members
  • 221 posts
  • London. UK

Posted 09 March 2008 - 11:37 AM

Surely that is precisely the effect one gets when you use talent mounted body rigs?
  • 0

#10 chris fawcett

chris fawcett

    Advanced Member

  • Sustaining Members
  • 1016 posts
  • Europe

Posted 11 March 2008 - 06:06 AM

I love this thread, Alan, and I apologise for sounding flippant in my first reply.

The point you raise is crucial to us. Like Imran says, if the shot really is zero acceleration with respect to the subject (or perhaps with with respect to any one element), it is like a body-cam or a tripod shot, or even a dolly shot of the type Brad describes. If the shot takes into account all the narrative elements, and is continuously changing velocity (and direction of reference) relative to them, it is a classic moving camera shot.

The stuff about Lagrange points is a complicated allusion I find illuminating when considering camera movement. I'll try to explain why. A Lagrange point is a place in space where you can place an object of negligible mass and have it stay put with regard to other objects. A satellite placed between the Earth and the Sun at L1 would provide a constant view of our day-lit hemisphere. In any two-body system there are 5 Lagrange points, and moving from one point to the other requires little expenditure of energy. In a more complicated system, there are numerous points. NASA calls this matrix the Interplanetary Transport Network, and uses it to move spacecraft around the Solar System.

In a moving camera shot, there are competing narrative potentials that demand our attention, and we have to balance them all to achieve a great take. I think that there are similar Lagrange points, places you just have to be to capture the action, each place giving a different perspective, with these places changing dynamically with respect to time. Equally, there are places you should never be. Like a body outside a Lagrange point requires energy to remain there, the camera draws attention to itself by being in the wrong place or moving in the wrong way.

The beauty of Steadicam is that we can dynamically accommodate changing narrative potentials on the fly, and dazzling work such as exhibited by Garrett Brown in Casino where we move effortlessly through a sea of narrative possibility, is like a spacecraft moving seamlessly through a series of Lagrange points. The fantastic energy of the shot entering the counting room comes not from barging around with a camera, but from the sensitivity of the operator in surfing the narrative potentials. The camera is always at the right place at the right time, and seemingly effortlessly.

We can't all achieve work of that calibre, but it's our duty to try.

Chris
  • 0

#11 Brad Grimmett

Brad Grimmett

    Advanced Member

  • Sustaining Members
  • 718 posts

Posted 11 March 2008 - 09:57 AM

Surely that is precisely the effect one gets when you use talent mounted body rigs?

No, I think it's different. A body mount will move up and down as the actor walks. And it will tilt, pan, and change height as the actors body moves, so the camera is accelerating, sometimes in the exact opposite direction that the actor is accelerating or moving. Steadicam is obviously different, as is the dolly shot I referred to. The steadicam allows us to see more like our eyes do. When you walk your eyes don't see the up and down movements of your body. Your eyes interpret your movement and remove the bobbing that your body is actually doing, just like steadicam.
  • 0

#12 Alan Dague-Greene

Alan Dague-Greene

    Advanced Member

  • Sustaining Members
  • 48 posts
  • Denver, Colorado

Posted 11 March 2008 - 09:13 PM

At the SOA workshop, we learned to break down a shot into parts, a process that has both physical and mental benefits.

In the physical sense, it's an opportunity to digest the shot in chunks, thinking in terms of it moving from point A to B, B to C, etc. It's important to nail the points, whereas the lines between the points may have some wiggle room (and if there are any errors, that's the time to correct them).

In the mental sense, it's an opportunity to understand the scene on a deeper level, to be in the scene with your actors and feel their motivation. This connects you to the action, and you can anticipate and understand movement on a more intuitive level.

I started this topic as a means of extending that mode of thinking (breaking down a shot) to perhaps absurd limits. I find that it's useful to think way too far out, so that you know the truth probably lies somewhere between here and there. Thanks to everyone for replying, and for not taking this too seriously! (Ssshpt, ssshpt...)

Chris, I'm not sure I understand Lagrange points yet, but you've done a wonderful job of relating the idea of narrative potentials. Like a satellite being slingshot around a planet, there's that specific place and time in a scene where the operator can be catapulted along with the story in exactly the right trajectory. Is that another way of saying it?

Alan
  • 0

#13 chris fawcett

chris fawcett

    Advanced Member

  • Sustaining Members
  • 1016 posts
  • Europe

Posted 13 March 2008 - 02:23 AM

Chris, I'm not sure I understand Lagrange points yet, but you've done a wonderful job of relating the idea of narrative potentials. Like a satellite being slingshot around a planet, there's that specific place and time in a scene where the operator can be catapulted along with the story in exactly the right trajectory. Is that another way of saying it?

Hi Alan,

I think it's not important how you visualise it, because it's all an intellectual exercise anyway. Anything that gets you thinking about the shots from a different angle is probably good. No, the slingshot is not quite what I was imagining, but it's an interesting extension. I'm thinking more about the "sweet spots" where it's just right to be, relative to the action?places that don't draw attention to the fact that a camera is present. The Lagrange points are places where bodies just quietly sit without drawing attention to themselves. It's a dumb analogy, perhaps, but it works for me. Here's a link you can surf off from. Check out Trojan asteroids and space elevators. Fantastic stuff.

Speaking of bongs, what do Rastas say when they run out of ganga?

"Well who the f**k put on this music?"
  • 0

#14 luis castro

luis castro

    Advanced Member

  • Sustaining Members
  • 245 posts
  • Spain

Posted 05 April 2008 - 12:39 AM

to think when to make a shot, to let take that steadicam makes its work flow with the single one to accompany to him as to dance walks that the fleet
  • 0

#15 Jess Haas SOC

Jess Haas SOC

    Advanced Member

  • Sustaining Members
  • 1145 posts
  • Culver City, CA

Posted 05 April 2008 - 04:03 PM

Alan, I though you didn't drink and assumed you didn't do drugs. If I was wrong would you please pass that shit this way? Sounds like some good shit :-)

~Jess
  • 0




Boland Communications

rebotnix Technologies

Betz Tools for Stabilizers

Omnishot Systems

Media Blackout - Custom Cables and AKS

Ritter Battery

PLC Electronics Solutions

Varizoom Follow Focus

PLC - Bartech

BOXX

Engineered Cinema Solutions

SkyDreams

IDX

GPI Pro Systems

Wireless Video Systems

Teradek

Paralinx LLC