Magic Lantern Forum

Using Magic Lantern => General Help Q&A => Topic started by: Aileron on January 07, 2019, 02:43:39 PM

Title: Can I sync my camera with an 8mm film projector using FPS override?
Post by: Aileron on January 07, 2019, 02:43:39 PM
Hi folks!
To install ML on my 5d3 I would need to downgrade the Canon firmware. Before doing so I'd like to find out how FPS override works. I would like to create a digital copy of several 8mm/Super 8mm films that were shot with 18 and 24 fps. I did a trial run yesterday (ISO 400, 1/30, f/2.4) and it was not too bad actually. I ran into the following problems though:

- Some kind of "banding" effect, meaning bars of darker areas that are moving slowly down
- When watching a single frame it occasionally looks like a double exposure, so the 5d3 obviously captured two film frames in one digital clip frame

Both artefacts are the result of the camera and the projector not being in sync. So I wonder if I can adjust the frame rate of the camera in .001-steps to better synchronize playback and recording speeds? To minimize the probability of the mentioned "double exposure" I'd just reduce the exposure time to a minimum - however, that turned out to increase the banding effect which appears quite logical to me.

However, my basic question is: Can I adjust the FPS setting in .001 steps?
Title: Re: Can I sync my camera with an 8mm film projector using FPS override?
Post by: Walter Schulz on January 09, 2019, 04:05:03 AM
Here is how another user solved sync problems. Requires some additional hardware + experimental build: https://www.magiclantern.fm/forum/index.php?topic=19300.msg190023#msg190023
Title: Re: Can I sync my camera with an 8mm film projector using FPS override?
Post by: Ant123 on January 09, 2019, 08:23:25 AM
There is another solution (https://avisynth.org.ru/getdups/getdups.html) without additional hardware. But you need to slow down your projector.
Title: Re: Can I sync my camera with an 8mm film projector using FPS override?
Post by: miket on January 10, 2019, 02:25:34 AM
Hello Aileron!
The short answer is that I don't think your camera can be synced to the projector with Canon or ML settings.  Mostly because the projector speed is not as precise or consistent as your digital camera.  The banding is most likely the projector shutter partly blocking the frame when the exposure is made in your camera.  The best video I have found to explain the projector operation is by the engineerguy you can check it out here https://www.youtube.com/watch?v=En__V0oEJsU (https://www.youtube.com/watch?v=En__V0oEJsU)

Thank you Walter Schulz for mentioning my project!  There are a couple more forum members that have built projects working along the same lines as mine.  I have not gotten back to my projector in a while, I still plan to and to post additional details on how and why I built it the way I did.  I also have a good 8MM/ Super 8 projector still to build for ML movie capture. 

If you only have a few film reels and you already have preview copies made you might consider looking for a hi-quality transfer service since a build like I did is time-consuming. If you search my previous posts there are some notes on setting up the 5D3 for frame by frame capture.  The biggest change that I need to make on my machine is to replace the reed switch trigger (not easy to get working right) with a hall sensor.  Good luck!
 
Mike
Title: Re: Can I sync my camera with an 8mm film projector using FPS override?
Post by: kaco on January 10, 2019, 03:58:42 PM
Quote from: miket on January 10, 2019, 02:25:34 AM
Hello Aileron!
The short answer is that I don't think your camera can be synced to the projector with Canon or ML settings.  Mostly because the projector speed is not as precise or consistent as your digital camera.  The banding is most likely the projector shutter partly blocking the frame when the exposure is made in your camera.  The best video I have found to explain the projector operation is by the engineerguy you can check it out here https://www.youtube.com/watch?v=En__V0oEJsU (https://www.youtube.com/watch?v=En__V0oEJsU)

Thank you Walter Schulz for mentioning my project!  There are a couple more forum members that have built projects working along the same lines as mine.  I have not gotten back to my projector in a while, I still plan to and to post additional details on how and why I built it the way I did.  I also have a good 8MM/ Super 8 projector still to build for ML movie capture. 

If you only have a few film reels and you already have preview copies made you might consider looking for a hi-quality transfer service since a build like I did is time-consuming. If you search my previous posts there are some notes on setting up the 5D3 for frame by frame capture.  The biggest change that I need to make on my machine is to replace the reed switch trigger (not easy to get working right) with a hall sensor.  Good luck!
 
Mike

Dear Mike,

is there any convenion way how to get in touch with you and discuss your telecine? I have built a similar telecine for 8mm, arduino powered stepper with optical trap and canon camera running ML for frame by frame capturing. However, I have few questions to ask, maybe sharing of knowledge would help?

Thank you!
Title: Re: Can I sync my camera with an 8mm film projector using FPS override?
Post by: Walter Schulz on January 10, 2019, 04:13:53 PM
Think about getting g3gg0 involved, too. He had the suggestion to sync the other way round using camera's LED to trigger stepper motor. Short mention about it in linked thread.
Requires a custom build, though.
Title: Re: Can I sync my camera with an 8mm film projector using FPS override?
Post by: kaco on January 10, 2019, 05:53:19 PM
Quote from: Walter Schulz on January 10, 2019, 04:13:53 PM
Think about getting g3gg0 involved, too. He had the suggestion to sync the other way round using camera's LED to trigger stepper motor. Short mention about it in linked thread.
Requires a custom build, though.

That's basically what my setup is doing. Remote controller cable connected to arduino doing half and full press, simple photoresistor reading camera LED and a optical trap stopping stepper motor when the film is at correct position.