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Shooting 4-6 fps? Possible with a intervolometer?


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#1 Norbert Shieh

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Posted 30 November 2007 - 04:52 AM

Looking to shoot 4-6 fps with a Bolex. The lowest it'll go is 12 fps with the motor.

Is there anyway to shoot faster than a single frame a second with an intervolometer? Would this be capable with using the shutter release cable and trying to time 4 fps?

Thanks!
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#2 Bernhard Zitz

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Posted 30 November 2007 - 05:39 AM

Is there anyway to shoot faster than a single frame a second with an intervolometer? Would this be capable with using the shutter release cable and trying to time 4 fps?


I'm able to shoot around 4fps with my diy intervalometer on a Rex1. This intervalometer hits the singleframe-button. If your fingers are fast enough you should reach 4fps with the release cable.

If you have a newer model with 1:1 shaft (rex4 and higher) you could also try an external motor for the older 1:8 models (pre rex4). The old motors turn 8times slower, if you run it at 24 fps you would end with 3 fps...

have fun, bernhard
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#3 Clive Tobin

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Posted 01 December 2007 - 08:33 PM

Looking to shoot 4-6 fps with a Bolex. The lowest it'll go is 12 fps with the motor.
Is there anyway to shoot faster than a single frame a second with an intervolometer?

Our TTL time lapse and animation motor will run all day at .75 FPS, or 1.25 FPS in "fast" forward. 4-6 FPS is kind of a no man's land that is too slow for smooth running with a 60 FPS-capable crystal motor, yet too fast for reliable long-lasting operation of an animation motor. An animation motor would beat itself to death running this fast into a mechanical stop. Our TTL should run about forever at .75 as at this speed it can stop fast enough with dynamic braking to not need a mechanical stop.
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#4 Dominic Alt

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Posted 02 December 2007 - 01:24 AM

Looking to shoot 4-6 fps with a Bolex. The lowest it'll go is 12 fps with the motor.
Is there anyway to shoot faster than a single frame a second with an intervolometer? Would this be capable with using the shutter release cable and trying to time 4 fps?

Our Revolution Motor for the Bolex (also available for Eyemo, Filmo, and more) will run from 1 fps to 48 fps, all crystal-sync, and also do the video speeds. Heck, it will even run backwards!

Posted Image

Read more about it here:
http://www.intervalo....com/rev/bolex/

You can watch it running at 4fps here.


It uses modern microprocessor control so it doesn't have the limitations of sync or single-frame motors based on ancient 1970s technology. ;) There's a Time Lapse/Single frame only model (which will run up to 6 fps sync), and one that does all that and adds sync 1-48 fps plus the oddball video speeds (29.97 and 23.976).

Oh, and I should mention that it has a full range of time-lapse features, including multiple shutter speeds and crystal-controlled intervals. Also programmable-shutoff, automatic filming, and lots more. And it drives the 8:1 shaft present on all the Bolex models, early and late, and it will even fit the EBM.

Posted Image
The TimeFlow (TIV) Intervalometer with Turbo Mode can run at 3 fps, but you have to ask that feature because (as of 2007) it's a custom feature. (In 2008 it gets added as a standard feature)
Bolex
Krasnogorsk-3
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#5 Clive Tobin

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Posted 04 December 2007 - 08:58 PM

... It uses modern microprocessor control so it doesn't have the limitations of sync or single-frame motors based on ancient 1970s technology. ;) ...

So, instead of ancient 1970s technology it is based on ancient 1960s stepping motor technology that we evaluated and rejected for several reasons?

Stepping motors by definition turn with small but violent steps, instead of turning smoothly. This is easily detected by your ear as a buzzing noise. This has the following drawbacks:

1. Constant flutter in the driving speed can be hard on the camera's gears. This has been demonstrated in the Arri 16-BL cameras when using the old governor motor. While not a stepping motor, it has the same "hitting" effect on the drive train, as it is constantly alternating between over and under speed at a high rate. It is known among repairmen that a 16-BL that has been used for a long time with the old governor motor is no longer able to take flickerless footage even when using a new type motor, owing to wear on the mirror shutter gear. This is an expensive repair.

2. The considerable vibration from the stepping motor can shake the camera and cause unsharp or unsteady pictures.

3. A stepping motor is an open-loop device instead of a closed loop servo. That is, the control electronics has no way of knowing if the stepping motor is actually doing what it is told to do. There is no simple means of providing an out of sync warning light. If the load is higher than anticipated, or the battery voltage is low, the stepping motor rotor will just sit there and vibrate instead of rotating as expected.

Our smoothly turning motors can be seen on the website.

Edited by Clive Tobin, 04 December 2007 - 09:02 PM.

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#6 Nick Mulder

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Posted 10 December 2007 - 12:04 AM

Stepping motors by definition turn with small but violent steps, instead of turning smoothly.

I built a version of the revolution system and jeez Reeves did it shake the camera ! I mounted it with a heap of dampening material which stopped it being so noisy but the drive train sounded ill ...

BLLLLAARRGH - BLLLLAARRGH - GIBBOOOBBBB - BLLLLAARRGH etc... :lol:

There were certain speeds where the speed of the step equated to the same rotational speed so it quietened down considerably, I had two of these speeds - one for wave (+ the other stepping method whose name escapes me) and one for micro (it wasn't simply a factor of two for some reason) so by either running in 8:1 or 1:1, I had four speeds - could be ok for a bolex based DSLR/telecine maybe

Anyhoo, I canned further work on it and once I settle down with all my work and build my CNC drives I may convert one to run a Bolex ...
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#7 Dominic Alt

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Posted 10 December 2007 - 05:11 AM

Let me see if I understand this correctly.

You tried to copy the Revolution Motor, and your copy didn't work as well as the original?
Wow, imagine that. :unsure:

From your description, it sounds more like you tried to copy the 'ThingM' motor or the Meritex 'ITSM' motor.
I will give you some pointers...after I respond to my friend Clive. :rolleyes:

Watch a video while you wait

Edited by Dominic Alt, 10 December 2007 - 05:11 AM.

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#8 Dominic Alt

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Posted 10 December 2007 - 07:23 AM

Clive! I didn't realize you were so sensitive!
I mean, your Bolex sync motor, being designed in the 1970's, had to use 1970's technology!
The original poster simply asked if there was a motor that ran at 4fps. You said that that wasn't possible. You were wrong.

You said it wasn't possible to design a crystal-sync motor for the Eyemo. You were also wrong about that.

Posted Image
Eyemo Running, 4fps and Sync


Stepping motors by definition turn with small but violent steps, instead of turning smoothly.

First of all, the motors we use are properly described as brushless synchronous AC motors. Synchronous means that the motor speed is controlled by the frequency of the applied signal. Brushless means there are no brushes, in that you have to externally commutate the motor. Now the colloquial term is 'stepper motor' because it's a lot easier to say then brushless synchronous AC motor.

Second of all, a 'stepper motor' doesn't do anything without being driven by a driver of some kind. If you use a 1970's-style driver, then you get the classic situation you describe, since the old-style drivers use a square-wave.

The Revolution Motor, being revolutionary :), doesn't use 1970's technology. It uses an ultra-modern driver that generates a sine wave (to be specific, a pair of sine-cosine waves). Thus, the motion is silky smooth, without the noise and vibration of a geartrain and DC motor combination.

But let's be honest Clive. Nobody would design a single-frame motor using a gearmotor. First of all, unless you change the gearing, you're limited to just one shutter speed, and it's a wild shutter speed! There's no regulation of the motor speed whatsoever. Just because you regulate the voltage applied to the motor, doesn't mean the speed is regulated. It is possible to get varying shutter speeds from frame to frame.

The real reason you designed your single-frame motor using a 1950's-style gearmotor, is because in order to use a digital motor, you need to use a digital microprocessor! Since you don't know how to program microprocessors, you didn't have any choice. You had to use a gearbox, coupled with a little microswitch (I'm assuming--have never looked inside of one), with some kind of 555-timer circuit to generate the interval.

Writing software to control a single-frame motor is not as easy as you'd think (as Nick discovered). Using a gearmotor is much easier. But the benefits of digital microprocessor control are incredible:
  • Crystal-controlled shutter speeds.
  • Multiple shutter speeds (from 1/8 to 1/2 sec, 1 sec on up )
  • Crystal-controlled intervals
  • Automatic shutoff
  • External light control (turn the light on a few seconds before the motor turns).
  • No gearbox to wear out and cause noise and vibration!
  • ...this list could go on until it got really boring...
Ok, we've talked about single-frame. Now let's talk about Sync.
The Revolution Motor is plenty smooth at single-frame operation and even smoother when running at sync! So #1 and #2 are silly.

3. A stepping motor is an open-loop device instead of a closed loop servo. That is, the control electronics has no way of knowing if the stepping motor is actually doing what it is told to do. There is no simple means of providing an out of sync warning light. If the load is higher than anticipated, or the battery voltage is low, the stepping motor rotor will just sit there and vibrate instead of rotating as expected.

Exactly! Since the Revolution Motor uses a synchronous motor, it is simply not possible for it to run 'out-of-sync' ! The motor must rotate at the speed determined by the applied sine wave. If the motor can't handle the load, it will let you know with a very audible indication. A motor using a phase-locked-loop (PLL) and encoder needs a warning light because otherwise you can't tell if it is running at sync or not!

Now remember when I said it wasn't easy to write the software to control single-frame operation? Sync is much harder! The software has to accelerate the motor to the desired speed, run it that speed, keep track of how many frames have been filmed, handle the 0.1% slowdown weirdness if running at the video speeds, decelerate to a stop, and then park the shutter!

Let's look at the advantages. First of all, there's no brushes to wear out, you can have the motor turn at any speed you want, you can park the shutter, ramp the speed, and you don't have to watch the sync alarm. You can even have the motor turn an exact number of frames and then stop! And then back up and return to the exact starting frame. But there is another big benefit.

Remember your Arri II motor debacle? Why did that happen? Well, the technique of using a PLL to control motor speed doesn't work so well when the motor is attached to a camera with a less-then-perfect drivetrain. Slop in the gears leads to surging in the motor speed and flicker in the footage. And a small army of incredibly upset filmmakers.

Just as you pointed out in #1, your motors have trouble dealing with cameras that have slop in the drive train. That doesn't make your motors bad, it is just a consequence of using a PLL for motor speed control.

The technique of using an AC syncronous motor is way older then the 1960's! I've read that in the earliest days of sync-sound filming, they would use syncronous motors in the camera and in the sound recording equipment, both run by the same generator, to assure sync.

The Revolution Motor is a 21st-century version of that concept, with the microprocessor generating the AC drive frequency. And a whole lot more. It's not the cheapest motor out there, but as my late grandfather told me, "Only a wealthy man can afford cheap tools". ;)

I didn't mean to offend you by describing your motor as 'ancient technology'. I don't even think I mentioned your motor directly. Let me state that I have installed and sold many of your Krasnogorsk-3 Sync Motors. Never had a problem with one!

And what do I keep on the workbench to check sync? I'm sure this looks very familiar to you.
Posted Image
Three of the LEDs were dim so I replaced them with orange ones. It's a handy little gizmo, nice solid feel, looks and works great! My only complaint is that you need a screwdriver to change the speed.

Ultimately, Clive, any camera motor exists only to enable the creativity of the filmmaker. We can leave all the technical mumbo-jumbo aside and state that anything that limits the creativity of the filmmaker is bad, anything that enables the creativity of the filmmaker is good.

The Revolution Motor lets the filmmaker unleash his or her creativity.

Shooting Animation? Want a 1-second shutter speed? Half-second? Eighth-second? No problem. 15-seconds? No problem, but maybe you should turn on some lights.
Shooting Time-Lapse? Want a 180-degree 'shutter angle'? Just dial it in, 1-second interval with a 1/2 second exposure. Want flowing, dreamy footage? Set the interval to '0' and bump-up the shutter speed? Not sure of the interval and shutter speed settings? Set the Presets and auto-expose with the Chaining feature.
Shooting Sync? Go ahead, shoot straight at 24fps. Or slow it down to 4 fps and see what comes out! Cap the shutter, auto-backwind, and layer another exposure on top!

And remember, that's all with one motor, on any Bolex, early or late model.

You've given me an idea for a slogan.
Unleash Your Creativity with a Revolution Motor

Hmm. I'll have to think about that. :rolleyes:
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#9 Mark Dunn

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Posted 10 December 2007 - 10:35 AM

Clive! I didn't realize you were so sensitive!
I mean, your Bolex sync motor, being designed in the 1970's, had to use 1970's technology!
The original poster simply asked if there was a motor that ran at 4fps. You said that that wasn't possible. You were wrong.

You said it wasn't possible to design a crystal-sync motor for the Eyemo. You were also wrong about that.

Posted Image
Eyemo Running, 4fps and Sync



First of all, the motors we use are properly described as brushless synchronous AC motors. Synchronous means that the motor speed is controlled by the frequency of the applied signal. Brushless means there are no brushes, in that you have to externally commutate the motor. Now the colloquial term is 'stepper motor' because it's a lot easier to say then brushless synchronous AC motor.

Second of all, a 'stepper motor' doesn't do anything without being driven by a driver of some kind. If you use a 1970's-style driver, then you get the classic situation you describe, since the old-style drivers use a square-wave.

The Revolution Motor, being revolutionary :), doesn't use 1970's technology. It uses an ultra-modern driver that generates a sine wave (to be specific, a pair of sine-cosine waves). Thus, the motion is silky smooth, without the noise and vibration of a geartrain and DC motor combination.

But let's be honest Clive. Nobody would design a single-frame motor using a gearmotor. First of all, unless you change the gearing, you're limited to just one shutter speed, and it's a wild shutter speed! There's no regulation of the motor speed whatsoever. Just because you regulate the voltage applied to the motor, doesn't mean the speed is regulated. It is possible to get varying shutter speeds from frame to frame.

The real reason you designed your single-frame motor using a 1950's-style gearmotor, is because in order to use a digital motor, you need to use a digital microprocessor! Since you don't know how to program microprocessors, you didn't have any choice. You had to use a gearbox, coupled with a little microswitch (I'm assuming--have never looked inside of one), with some kind of 555-timer circuit to generate the interval.

Writing software to control a single-frame motor is not as easy as you'd think (as Nick discovered). Using a gearmotor is much easier. But the benefits of digital microprocessor control are incredible:

  • Crystal-controlled shutter speeds.
  • Multiple shutter speeds (from 1/8 to 1/2 sec, 1 sec on up )
  • Crystal-controlled intervals
  • Automatic shutoff
  • External light control (turn the light on a few seconds before the motor turns).
  • No gearbox to wear out and cause noise and vibration!
  • ...this list could go on until it got really boring...
Ok, we've talked about single-frame. Now let's talk about Sync.
The Revolution Motor is plenty smooth at single-frame operation and even smoother when running at sync! So #1 and #2 are silly.


Exactly! Since the Revolution Motor uses a synchronous motor, it is simply not possible for it to run 'out-of-sync' ! The motor must rotate at the speed determined by the applied sine wave. If the motor can't handle the load, it will let you know with a very audible indication. A motor using a phase-locked-loop (PLL) and encoder needs a warning light because otherwise you can't tell if it is running at sync or not!

Now remember when I said it wasn't easy to write the software to control single-frame operation? Sync is much harder! The software has to accelerate the motor to the desired speed, run it that speed, keep track of how many frames have been filmed, handle the 0.1% slowdown weirdness if running at the video speeds, decelerate to a stop, and then park the shutter!

Let's look at the advantages. First of all, there's no brushes to wear out, you can have the motor turn at any speed you want, you can park the shutter, ramp the speed, and you don't have to watch the sync alarm. You can even have the motor turn an exact number of frames and then stop! And then back up and return to the exact starting frame. But there is another big benefit.

Remember your Arri II motor debacle? Why did that happen? Well, the technique of using a PLL to control motor speed doesn't work so well when the motor is attached to a camera with a less-then-perfect drivetrain. Slop in the gears leads to surging in the motor speed and flicker in the footage. And a small army of incredibly upset filmmakers.

Just as you pointed out in #1, your motors have trouble dealing with cameras that have slop in the drive train. That doesn't make your motors bad, it is just a consequence of using a PLL for motor speed control.

The technique of using an AC syncronous motor is way older then the 1960's! I've read that in the earliest days of sync-sound filming, they would use syncronous motors in the camera and in the sound recording equipment, both run by the same generator, to assure sync.

The Revolution Motor is a 21st-century version of that concept, with the microprocessor generating the AC drive frequency. And a whole lot more. It's not the cheapest motor out there, but as my late grandfather told me, "Only a wealthy man can afford cheap tools". ;)

I didn't mean to offend you by describing your motor as 'ancient technology'. I don't even think I mentioned your motor directly. Let me state that I have installed and sold many of your Krasnogorsk-3 Sync Motors. Never had a problem with one!

And what do I keep on the workbench to check sync? I'm sure this looks very familiar to you.
Posted Image
Three of the LEDs were dim so I replaced them with orange ones. It's a handy little gizmo, nice solid feel, looks and works great! My only complaint is that you need a screwdriver to change the speed.

Ultimately, Clive, any camera motor exists only to enable the creativity of the filmmaker. We can leave all the technical mumbo-jumbo aside and state that anything that limits the creativity of the filmmaker is bad, anything that enables the creativity of the filmmaker is good.

The Revolution Motor lets the filmmaker unleash his or her creativity.

Shooting Animation? Want a 1-second shutter speed? Half-second? Eighth-second? No problem. 15-seconds? No problem, but maybe you should turn on some lights.
Shooting Time-Lapse? Want a 180-degree 'shutter angle'? Just dial it in, 1-second interval with a 1/2 second exposure. Want flowing, dreamy footage? Set the interval to '0' and bump-up the shutter speed? Not sure of the interval and shutter speed settings? Set the Presets and auto-expose with the Chaining feature.
Shooting Sync? Go ahead, shoot straight at 24fps. Or slow it down to 4 fps and see what comes out! Cap the shutter, auto-backwind, and layer another exposure on top!

And remember, that's all with one motor, on any Bolex, early or late model.

You've given me an idea for a slogan.
Unleash Your Creativity with a Revolution Motor

Hmm. I'll have to think about that. :rolleyes:


Am I alone in thinking that a post like this should be in the classified section? With the knocking copy removed, preferably.
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#10 Nick Mulder

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Posted 10 December 2007 - 02:50 PM

Let me see if I understand this correctly.

You tried to copy the Revolution Motor, and your copy didn't work as well as the original?
Wow, imagine that. :unsure:

From your description, it sounds more like you tried to copy the 'ThingM' motor or the Meritex 'ITSM' motor.
I will give you some pointers...after I respond to my friend Clive. :rolleyes:

Watch a video while you wait


We'll I've never touched one, just seen pictures of it on the net - so yes and no, I saw some sort of controller that I assumed could control the shutter speed in both continuous and stop start fashion (duty cycle/'shutter angle') and what looked like a stepper motor so thought I'd give it a crack for shits and giggles - it took me about a day to build the mount and program a uP with an LCD, it ran using discrete frequency units rather than period as an input which was annoying and a problem to be solved but I stopped because I had other things to do and it was scaring the cat.

I imagine yours took a bit longer than a day ...

Thanks, looking forward to those pointers!

Nick
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