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Aaton 35-III to film computer screen


Dirk DeJonghe

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I need to film a computer screen, about 2K -4K resolution. The footage is at 25 fps;

I am trying to use an external sync box (from PAL days)  but cannot shift the phase so my film frame starts at the same time as the digital frame, giving a half frame dissolve instead of a clean cut;

Any suggestions how to handle this?

 

 

 

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is it a modern LCD? if so, make sure its running at a higher refresh rate, ideally at a frame rate divisible by 25. 

My experience has been that when shooting 24 fps, on a tv or LCD running at 60htz or higher theres no real issue shooting a TV screen without a sync box. This comes from the LCD holding on a given frame for a few cycles before it changes (when your video on the display is fewer fps than the monitor refresh rate). 

On one rear projection job (projector was running at 120htz) we considered plugging the camera and projector into the same circuit to phase jam them that way, but it wasnt necessary (this was with an alexa on battery). For... reasons... the source video playback was actually at 30, but there was no artifacting or anything weird on the final shot. 

If you have a DSLR or even an iphone handy, do a test filming the monitor you want to use. if the refresh rate is high enough you probably wont have any issue. 

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I see. For frame by frame shooting you would need a capping shutter - and only works if there is nothing else moving in the shot. This is a silly idea, but if it's a short sequence, shoot it multiple times. The image change has to happen during the 180 degree transport phase of the film, so there's a theoretical 50 50 chance. So when you shoot let's say a 5 second scene 5 times, hopefully in one of the shots, the image change happens during the dark 180 degree transport phase. Yeah it's a crude and silly idea ?

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  • 3 months later...
On 7/27/2022 at 7:15 AM, David Sekanina said:

it's a crude and silly idea ?

It's not- it's a variation on how we were told to do it at film school. Just blip the start button a few times until you see the flyback bar close to the top (or bottom) of the screen. The mirror and film are 180deg out of phase so the bar will record at the bottom (or top) of the screen.

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