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360 degree pan in precisely 48 seconds. How?


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I am trying to figure out a way to execute a shot that requires completing a 360 degree revolution in 48 seconds, EXACTLY. Why exactly? Well, because I have a 48 second pre-recorded cue and the move is choreographed to fit the cue.

 

I am on a tight budget and schedule (aren't we all) and don't have the luxury of spending several hours trying to complete this movement manually. How can one accomplish this with precision in a time-efficient manner?

 

I was thinking that perhaps one of those time-lapse heads would work if I could input the time (i.e. 48 seconds) and degrees (360°).

 

I am using a Black Magic 4K.

 

Any suggestions would be appreciated!

 

 

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The way to do it with the utmost precision would be on a motion control crane, but that's a very expensive option. Personally I'd probably just time it out with a stopwatch and make some marks somewhere that I could refer to.

 

P

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If the motion is choreographed with talent then speeding it up and slowing down in post wont work... (well, that's the safer assumption at least)

 

Howabout just a head with a motor input ? No need for a full crane (!)

 

Lots of bodges like steppers/arduino/lazy susan set ups to be hacked together if that's your style/budget ...

 

Once you have it going the next question is how to coordinate all the elements to be in sync with each other - in other words, when/what position do you start the rotation...

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If it'll go fast enough, I guess. Some people have modified telescope mounts to do similar things, but I'm fairly sure they wouldn't go all the way around in the time you need.

 

You could always bodge something up with a motor and gearbox.

 

P

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I am trying to figure out a way to execute a shot that requires completing a 360 degree revolution in 48 seconds, EXACTLY.

 

 

Do the start and end frames have to precisely match?

Is the camera paning or static at the start and end of shot?

Is the cut/transition into and out of the shot hard or soft?

 

Just some questions that came to mind that might affect how easy this is to do.

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Thanks Greg - here are the answers to your questions...

 

Do the start and end frames have to precisely match? Only in the sense that the frame must return to the woman's face. See below...

Is the camera paning or static at the start and end of shot? INT. LIVING ROOM - NIGHT - FADE UP onto a WOMAN's FACE (STATIC SHOT). Now, CAMERA PANS around FOUR OTHER FACES and return onto original WOMAN's FACE. The woman begins to pray. CUT TO: INT. ENTRY - CONTINUOUS.

Is the cut/transition into and out of the shot hard or soft? See above.

 

Just some questions that came to mind that might affect how easy this is to do.

Edited by Eric Novakovich
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I noticed that no one has addressed the time lapse head. Is this because it will not work?

 

Gregg has asked the direct questions that I alluded to above also - they'll need some consideration.

 

David, I agree that an operator could achieve a total of 48 seconds for the total move (esp, with a countdown as you mention), but what an operator will struggle with relative to that task is maintaining a constant rotational velocity throughout the move - something we're not 100% sure is a design spec at this stage - Eric?

 

360/48 = 7.5 deg/s

 

As Phil points out a timelapse head may not have that capability directly but maybe you can gear it, or change the timing divisor in code (electronic gearing). Who knows, suspect it's trivial but really up to the initiative of the person you end up renting it from.

 

A web search of 'motion control pan head' reveals many off the shelf solutions also.

 

What is your budget? ...and the same question but from another perspective: are you tinkering or is this a paid job?

Edited by Chris Millar
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I would think that an operator within a few takes could get to the end of a 360 degree pan at exactly 48 seconds if someone did a countdown for him.

 

Exactly my thinking, which is why I asked if it was MOS.

 

I do run-throughs with basic set-ups, so why wouldn't you do it with this - somewhat more complex - set-up? Automation is not always the sure-fire way to go. All you really need is a good camera operator & a few takes and you should be good.

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You could certainly do it with a motion control system, perhaps tied to something simple like Hot Gears on a geared head, the operator would do it a few times until it was 48 seconds long and then be able to repeat the move. But I don't see why the simplest solution isn't the best, just let the operator do it to a countdown (if you are recording dialogue then do it thru a headset). Using a geared head would make it feel more precise and robotic.

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... but what an operator will struggle with relative to that task is maintaining a constant rotational velocity throughout the move - something we're not 100% sure is a design spec at this stage - Eric?

 

... by 'constant' I mean not just an average of 7.5 deg/s - but 7.5 deg/s for the whole move ...

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  • 4 weeks later...

I'm sure there are more advanced ways of getting this shot. Motion-controlled gear that can carry a ALEXA fully rigged and what-not. However I have been on set where the cam op rigged a kitchen timer with a 1/4 inch mount and was able to achieve a 360 degree shot. This is obviously an option for much smaller cameras with a set-it-forget-it focus setup but It may be worth testing depending on how much you can scale back your rig on the blackmagic.

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Following onto Tyler Clark's suggestion. Get a 1 RPM synchronous motor. It's speed is exactly determined by the AC frequency, nominally 60Hz. Feed it 75 Hz instead. You can make that exact AC as an audio signal and transform to the needed voltage. So, no need for gearings or tachometers, just an accurate audio oscillator.

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  • 8 months later...

If you can set your fluid head to the pan to the heaviest setting and lock the tilt, then extend one handle to the longest possible setting. If you can get two to three feet of handle, you're half way there.

Run to a hardware store and find the longest painter's pole you can find. Gaffer tape one end to the handle extension as rigidly as possible. Three feet of pole and three feet of handle should be super strong.

 

Rehearse the move:
Grab onto the farthest end of the pole. You won't need to jerk it as it has much leverage to pan the camera. In fifteen seconds, you should have covered 90 degrees. In another fifteen, the second 90 degrees. In 45 seconds from starting, you're 3/4 of the way done. In 60 seconds, you should have traversed your entire 360 degrees.

In post production, you take your 60-seconds clip and do a time stretch, shrinking your 60 seconds to the prerequisite 48 seconds. Using this technique will get you super accurate results down to almost 24-30 frames.

 

And you'll hit your cue no matter what.

Edited by Larry DeGala
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Following onto Tyler Clark's suggestion. Get a 1 RPM synchronous motor. It's speed is exactly determined by the AC frequency, nominally 60Hz. Feed it 75 Hz instead. You can make that exact AC as an audio signal and transform to the needed voltage. So, no need for gearings or tachometers, just an accurate audio oscillator.

 

Not going to work, a 1 RPM motor won't have the torque necessary. That's why most rotating devices start out with a higher rpm motor and gear it down, halving the RPM doubles the torque available.

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