My practical & simple frame-by-frame 8mm film scanning setup, that WORKS

[Shane Graber]

And regarding the speed since I'm capturing at "only" 5 Megapixel (2,624*1,968) resolution with UHSII card it should, in theory, be able to speed up to something 5-6 fps.

Remind me why you're only capturing at 5 MP? Your GH5 can do ~ 20 MP if I recall correctly.

[Robert Held]

I am curious what your trigger and stepper setup is and how you have this wired - is there any chance of a rough sketch for the wiring with the Arduino and motor?

Sure, I'll put something together in the next day or so. I use an off-the-shelf stepper driver, which makes things easy.

[Jacek Kropinski]

Thank you Robert Held I don’t mean to impose but it would be great to see a reliable setup since there are sooooo many various triggers I’ve seen, from reed switches to optical and jerry-rigged cams.

My interest lies in a minimally invasive way of advancing old and brittle film, perhaps in calibrating a stepper to advance one frame at a time with capstan drive rather than film sprocket drive.

I’ve been studying various proximity, optic and IR sensors. But as a devotee to Occam’s law, and highly experienced in digital post production, I think scanning a wide frame and later stabilization with planar tracking in software is the simplest solution. As long as I can get each frame reasonably similar in capture.

Maybe I’m naive but with the incredible accuracy of steppers and their minimum 1.8 degree of advance, it must be possible.

[Robert Held]

Hi Jacek,

No worries. Happy to help. Yes, there are a lot of triggers and ways to run a stepper motor. I have no idea if the way I set it up is best or efficient, but it works for me.

On and off, I've been working on designing a scanning system as you describe, but just haven't had the time to get to the build stage. And I get such good results with the setup I have, that I don't have much incentive. Of course, it does require film in good shape with good sprocket holes.

I don't have to do any stabilization; frame-to-frame variance is +/- 3 pixels out of 2448, which is just not visible in motion. I suspect that as long as the film doesn't slip on the capstan design you're suggesting (and if it's very round), you should have similar results. Steppers are pretty accurate, usually +/- 5% for the hobby grade ones I'm using. I'm sure more accurate, and more expensive, ones can be purchased. There are also 0.9 degree steppers, which obviously give more precision.

Below is a very crude schematic that I cobbled together from various websites with information on the stepper driver, relay and Lumix trigger. Power to the Arduino is not shown, but I run mine on 12VDC, which is the max it can take. Stepper motor wire colors may vary. For the camera wiring, I bought the remote trigger listed below and cut the plug off that goes to the button switch. The resistors are built in to the wiring. Focus, which represents a half push on the camera's actual shutter button isn't used, as I manually focus before I start the capture. The relay is a bit annoying as it clicks every time the contacts are closed, but I like to have the camera's trigger electrically isolated from the Ardiuno.

The Ardiuno program is at the bottom. Please let me know if you have any questions.

Best wishes,

Robert

Components used:

Nema 17 Stepper Motor: https://www.amazon.com/gp/product/B00PNEQKC0
DM320T Stepper Driver: https://www.amazon.com/gp/product/B075R88FMN
SunFounder 2 Channel DC 5V Relay Module: https://www.amazon.com/gp/product/B00E0NTPP4
Lumix Remote Camera Trigger: https://www.amazon.com/gp/product/B07L74HGQP


#include <Stepper.h>

const int stepsPerRevolution = 1600;
const int shoot = 10;

Stepper myStepper(stepsPerRevolution, 8, 9);


void setup() {

pinMode(shoot, OUTPUT);
myStepper.setSpeed(150); //speed is in RPM;
Serial.begin(9600);

}

void loop() {

// Serial.println("clockwise"); //controls the direction of the stepper motor;
// myStepper.step(stepsPerRevolution);
// delay(800); //the delay time between turns;

Serial.println("counterclockwise");
myStepper.step(-stepsPerRevolution);
delay(800);

digitalWrite(shoot, LOW);
delay(200);
digitalWrite(shoot, HIGH);
delay(100);


}

[Nantawat Kittiwarakul]

Remind me why you're only capturing at 5 MP? Your GH5 can do ~ 20 MP if I recall correctly.

Simply put - that's overkill for my application.

80% of my customers are still happy with 1080p output resolution, and the rest are happy for 1440p resolution. 1,968 pixels frame heigh had already gave me almost twice "oversampling" which results in noticeably better detail than capturing at native 1080p resolution.

Capturing at 20 megapixels MAY give better result. However I'm wondering if it's really that noticeable. But one thing for sure is that it will consume more resource & time & cost, for the very same job. Speaking about dimishing return - quadruple the input for some 5% increase at the output...

I believe that had now achieved the "sweetest spot" of my setup & the workflow. Therefore it would remain unchanged for the moment, and in foreseeable future.

[Shane Graber]

80% of my customers are still happy with 1080p output resolution, and the rest are happy for 1440p resolution. 1,968 pixels frame heigh had already gave me almost twice "oversampling" which results in noticeably better detail than capturing at native 1080p resolution.

Thank you for that. Makes perfect sense. My converted projector just made its first movements yesterday so I'm really excited. Now I just need to convert the wired remote for the Lumix G85 to use a hall effects sensor and I'll be all set to test it when my camera arrives from mpb.com.

[Shane Graber]

The post wouldn't take my photos for some reason, so here they are:

[Jacek Kropinski]

Hi Jacek,

No worries. Happy to help. Yes, there are a lot of triggers and ways to run a stepper motor. I have no idea if the way I set it up is best or efficient, but it works for me.

Wow Robert Held Thank you so much! This is amazing - I was expecting just a simple sketch
Yeah, my problem is the film was not well stored nor projected, so the sprockets are not in great health. I want to avoid damaging them even more.
This is a massive help and I am extremely grateful. Thank you again.

[Robert Held]

Jacek,

You're very welcome. Good luck! Torn sprockets are a pain. I've repaired some with splicing tape, but it only really works if a reasonable number are damaged.

[Robert Held]

Shane,

That's a nice design with the gears; very creative!

[Shane Graber]

That's a nice design with the gears; very creative!

Thanks! My goal was to not hack up the projector any more than needed as I could revert the changes easily if needed. I still feel bad about filing the film gate opening larger but it is what it is. The geared design really was the only option with this projector as I couldn't find an easier way to move the film with the way the projector is designed. I shot a short video of it running if anyone's interested: https://photos.app.goo.gl/LRqYXoRm6Xguh5Rp6

[Jacek Kropinski]

a hall effects sensor and I'll be all set to test it when my camera arrives from mpb.com.

I love the simplicity and elegance of your design Shane Graber Very well done, congratulations.
Seems that a 3d printer for gears etc is almost a necessity now.

Curious what that sensor is you have near the flywheel? Is that the hall effect sensor or a reed switch?
Seems simple to hook that up to a wired remote on your Lumix, no?
I found a great cheap remote to experiment with on AliExpress for $3
https://www.aliexpress.us/item/32568...yAdapt=glo2usa

[Shane Graber]

Curious what that sensor is you have near the flywheel? Is that the hall effect sensor or a reed switch?
Seems simple to hook that up to a wired remote on your Lumix, no? I found a great cheap remote to experiment with on AliExpress for $3
https://www.aliexpress.us/item/32568...yAdapt=glo2usa

It's a hall effect sensor: https://www.amazon.com/gp/product/B01NBE2XIR/ I thought about using a mechanical microswitch, but I've seen them fail as they obtain mileage. A 3-minute reel of Super8 will have ~ 3240 pictures taken and I have about 40 of those to convert along with some 5", 7" and 9" reels as well. It's too much to chance. All I need to do is superglue a small neodymium magnet on the 3D printed disk in the appropriate place to actuate it as the film advances. I'll probably just grab a generic Panasonic shutter release from Amazon as I'll get it sooner than if I order from AliExpress. I'd like to finish up the work on the setup while I'm off for the holidays so I can start converting everything in January.