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Simulate photography flash without rolling shutter effect?

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#1 Roger Alexander

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Posted 04 February 2017 - 04:01 PM

I want to simulate a red carpet scene for a music video where the aritst gets out of the car and is bombarded by multiple photographers when getting to the red carpet. They are flashing and taking photos all in his face. I want to see the flashes but without the rolling shutter effect (example attached) while shooting on RED dragon. Does anyone know of alternative ways to achieve this? Is there a special type of light/strobe that is long enough not to see this effect? My first thought was to shoot this scene on a camera with global shutter, but Id rather keep it all on my RED dragon and not have to color match later.

 

Is there a particular combination of frame rate and shutter speed I can set to fix this?

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#2 Jaron Berman

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Posted 04 February 2017 - 06:57 PM

I have used this technique with other rolling shutter issues, but it will likely work fine for your purpose.

 

Use real flashes as-is.  Shoot 120fps/360 shutter and use software called RealD Truemotion.  http://reald.com/#/truemotion

Obviously test first, but it should work fine.

 

With some cleverness you can do this even for sync-sound, but from your description you may not even need sound.  Pretty impressive software, I just started using recently for rolling-shutter-prone situations.  Instead of swapping to global cams, we use this trick and its been a lifesaver (but I haven't tried with a strobe situation)


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#3 David Mullen ASC

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Posted 04 February 2017 - 07:19 PM

Atomic LED strobes were used on "Straight Outta Compton" on a Red camera without rolling shutter artifacts:

http://www.martin.co...atomic-3000-led

 

I used an LED strobe the other week on a project without rolling shutter problems on the Alexa.


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#4 Phil Rhodes

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Posted 04 February 2017 - 08:01 PM

Alexa has extremely brief readout and is much less likely to suffer this problem than almost any other rolling-shutter camera; however, it is still quite possible (assuming this is the A-camera used on Terminator Genisys, which was apparently Alexa):

 

rsn_rollingshutter_terminator_1.png

 

Shooting high frame rate may reduce the likelihood of torn frames in terms of per frame artefacts, but the likelihood of at least one occurring in a given time window may actually increase. Shooting very wide shutter angles won't usually make much difference.

 

The correct tool for the job is an Outsight Creamsource and their Flashbandit accessory, which allows the camera to be connected to the light for reliable synchronisation. As far as I know this is the only available commercial solution. I have one here on review and intend to evaluate it with an Ursa Mini 4.6K.

 

You'd probably want several, in different positions, to simulate a press pack.

 

P


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#5 Satsuki Murashige

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Posted 04 February 2017 - 08:19 PM

Can you rent or borrow a Motion Mount for your Dragon? That might be the cheapest solution.
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#6 Roger Alexander

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Posted 04 February 2017 - 09:02 PM

I have used this technique with other rolling shutter issues, but it will likely work fine for your purpose.

 

Use real flashes as-is.  Shoot 120fps/360 shutter and use software called RealD Truemotion.  http://reald.com/#/truemotion

Obviously test first, but it should work fine.

 

With some cleverness you can do this even for sync-sound, but from your description you may not even need sound.  Pretty impressive software, I just started using recently for rolling-shutter-prone situations.  Instead of swapping to global cams, we use this trick and its been a lifesaver (but I haven't tried with a strobe situation)

This is great. I will run some tests.

 

for the shutter, are you saying 1/360th or 360 degrees?


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#7 Stuart Brereton

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Posted 05 February 2017 - 02:29 AM

The correct tool for the job is an Outsight Creamsource and their Flashbandit accessory, which allows the camera to be connected to the light for reliable synchronisation. As far as I know this is the only available commercial solution.

Actually, Lightning Strikes make a unit called the Paparazzi light which is specifically designed for this effect.


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#8 Phil Rhodes

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Posted 05 February 2017 - 05:16 AM

Yes, but is there a camera sync option for it?

There is often talk of using a long flash duration (apparently they'll do 1/24s) to avoid rolling shutter issues, but it doesn't work like that - no matter how long the flash is, or how high the frame rate is, or how wide the shutter angle is, the light can still turn on or off during a readout.

There needs to be at least a phasing option and ideally a sync input.
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#9 Jaron Berman

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Posted 05 February 2017 - 01:24 PM

There are tons of solutions for lighting the set in sync with a rolling shutter camera, but a lot fewer options when you want a press-pool full of practical flashes coming from the cameras themselves.  Maybe I misunderstood the idea, but to see the flashes themselves coming from the cameras, it's worth at least testing tessive.  And yes - 360 degree shutter/open shutter

 

For lighting the set, another thing you may try would be small halogen pars (75w) on dmx dimmer packs - if you run a chase on the dimmer packs, the tungsten element should naturally work and still look fast enough to pass for a "flash."  Whether something like a magic gadgets or a DMX solution, you should have plenty of control over the speed of the flickers (I prefer DMX because it's a lot cheaper and more flexible) - but a simple random  flicker chase on a 6-ch dimmer pack should get the effect, and the tungsten filaments should feather the timing enough to appear realistic without tearing the frames.


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#10 David Mullen ASC

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Posted 05 February 2017 - 01:33 PM

You could also try old-fashioned flashbulbs, some prop people have a homemade tray that holds a row of them that can be triggered.


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#11 Bruce Greene

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Posted 05 February 2017 - 03:38 PM

I have a collection of old flash bulbs that work very well, but I'm running low now...

Problem is I'm afraid to try and take them on a plane, as they might not pass security :)


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