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Homemade Telecine

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  • Stan Jelavic
    replied
    Actually this setup may work. With the gate that I am using the perforations are not visible. I will try a different cover with a larger opening to get the perforations in the camera view. That way a de-shaker can be used. The sync wheel still may be needed to eliminate the drift since the freewheeling method without the sync wheel will always have some very small drift preset.
    OK opened up the gate opening and now I can see the sprocket hole:
    https://photos.app.goo.gl/KfUAiZeuHPJf69n36
    Will try the de-shake avi script from Mattias:
    https://8mmforum.film-tech.com/vbb/f...3022#post13022

    Last edited by Stan Jelavic; September 26, 2021, 11:10 AM.

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  • Stan Jelavic
    replied
    It does drift but it has a jitter (shake) around it. The drift can be eliminated by tuning the number of steps per frame. I got pretty close but still needs more work. The sync wheel can also be used as a feedback to get the drift eliminated (phase locked loop). But the main problem is the shake. I will check the stepper tomorrow by pointing the camera at the sync wheel and observe the edges for shake.
    In this project below a stepper was also used and the test clip also has some shake similar to mine.
    https://www.instructables.com/28-mm-Digital-Telecine/
    Also
    https://www.chrisgavin.com/search/label/telecine
    So, looks like the shake is inherited in the transport using the stepper motors. Gris Gavin used the After Effects stabilizer and the resulting video seems pretty good.

    Leave a comment:


  • David Brown
    replied
    Stan, I wish you the best here. I'm going to cry UNCLE.

    Unless it is possible for the motor to move different distances, I can't understand the moving frame line. If the step distance moves more or less than the film frame spacing, the frame line would continuously drift up or down.

    Sadly, using the motor alone looks worse than it does with the sensor wheel.

    The raw Hawkeye clip looks ok to me. There are tiny frame line movements up and down. If the image is cropped that is not perceptible with the camera panning.

    Leave a comment:


  • Stan Jelavic
    replied
    Sorry David, posted a filtered video.
    Here is the raw video with the sync wheel:
    https://drive.google.com/file/d/12-m...ew?usp=sharing

    And here is the raw video without the sync wheel, just a fixed motor advance frame by frame.
    https://drive.google.com/file/d/1cRB...ew?usp=sharing

    The second video still has a drift which is not a big concern, but the shake is still there. It could be caused by the film stretch. I believe you had a similar issue. I will fix the drift tomorrow and then rerun the test. Will also compare the same footage with the Hawkeye capture.

    Actually, I like the drawing boards and puzzles, keeps my brain going.


    Here is the raw Hawkeye clip. There is some shake but seems to be lot less than in the second video. Will have to put them side by side.
    https://drive.google.com/file/d/1qM2...ew?usp=sharing
    Last edited by Stan Jelavic; September 24, 2021, 09:24 PM.

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  • David Brown
    replied
    Oh no, not the drawing board! Hope you enjoy puzzles.

    The frame movement does not seem to have a repeating rhythm. There are 243 frames in the video.

    The bottom of the frame never drops below the starting point of the first frame.

    Up and down movements are small with occasional large jumps.

    Frame 36 hit the highest point above starting, once and never again.

    I don't know how much work it would be to bypass the wheel and light sensor.

    Have the motor move a fixed amount (0.1667"), wait for the camera, and repeat?

    Seems easy, but I don't know how to do that.

    Leave a comment:


  • Stan Jelavic
    replied
    Tested the new sync wheel and it works better but the shake is still too high in my opinion.
    https://drive.google.com/file/d/1sDx...ew?usp=sharing

    Not sure what the cause of shake is. Perhaps the wheel tolerances or maybe the way the optical coupler triggers, not sure at this point.
    Will have to rethink this approach I guess.
    Here is the picture of the new rig.
    https://photos.app.goo.gl/z3NQjxGjeUYZ9DsR8
    Everything is pretty solid in the film transport so do not think that the shake is caused by the things being loose. Oh, well, back to the drawing board.

    Leave a comment:


  • Stan Jelavic
    replied
    Hi David. Not sure why he has extra wires there. He has several designs and also managed to get the scan working with the stepper and Arduino which sounds promising.

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  • David Brown
    replied
    Thanks Stan, I just might test that simple gate idea. Odd, just 2 pieces of plastic over a light source, what's with the 4 wires??? !

    Click image for larger version

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    I bought an 8mm carrier for my Cannon scanner several years ago, but I decided 8mm film was too small for the scanner's resolution. Flatbed scanners exaggerate their resolution, just like the Wolverine.

    Several film carriers came with that scanner, but not 8mm. I bought one from Amazon (printed) made to fit my Canoscan 9000, about 6 years ago. It's still available for sale. It's not unlike the simple gate.

    Click image for larger version

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    https://www.amazon.com/s?k=Negative+...ref=bl_dp_s_we b_0

    Also, I found a sound projector selling for parts on Ebay. $40 and free shipping. Shipping has to cost ~$40? It will have a gate and there is a very large sprocket wheel that might be useful. What worries me is that it might be in working condition! The seller doesn't know if it works or not, it's missing a power cord!


    Attached Files

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  • Stan Jelavic
    replied
    Here is a simple gate design David.
    https://www.youtube.com/watch?v=ltHuyay-2Os
    It does not touch the film only the edges which minimizes the film damage.

    If done in smooth fine plastic it should not scratch the film.
    Two rubber bands can be used to control the tension.
    Alternatively, two springs with adjustable top bracket can be used.

    Thought you may be interested in trying this.


    Leave a comment:


  • Stan Jelavic
    replied
    Hi David. I did receive the new sync disk but it is too transparent so I painted it black. Will try it soon after finishing a few Hawkeye orders. People are still buying the kit but it is still small qty that does not justify auto assembly. So I do it manually which is a pretty tedious process. If this was my prime job I would be a poor man for sure, but I do it because I like it.
    I agree, printing the new film gate is a pretty tricky business. You do not want to damage the precious old memories. The tension also has to be right etc etc.

    Leave a comment:


  • David Brown
    replied
    Hi Stan. Just playing cheerleader. You probably don't have parts yet or have doubts about accuracy of this method.

    I think I will divert my interest from the DSLR project to this one. The Winait scanner I bought has instability in both x and y axes. Slowing the speed might help, not sure. Slowing it down only makes real time video capture even harder.

    I still want a DSLR motion capture option. I can do still capture, it is a little cumbersome. So, looking for projector parts on ebay. Specifically gates, both 8 or S8. Either one could work if the framing mask is removable. Not sure if printing a gate is a good idea. Smooth surfaces are very important.

    Leave a comment:


  • Stan Jelavic
    replied
    The wheel notches synchronize the stepper. The stepper runs until there is a positive pulse from the wheel. Then it stops for a few seconds and sends the trigger to the cam and then continues running until it gets another positive pulse.
    I can see imperfections in the print. They appear as small bumps. Going with fine detail plastics may be better. Ordered the part several day ago and should be getting it soon.
    The width of the notches really does not matter since the MSP430 is detecting the first edge only.

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  • David Brown
    replied
    Hey Stan looks like I have finished my reading, at least the new stuff. I will need to review things leading up to the "homemade telecine" and Bruce's struggle with HDR, though his issue is different than mine.

    Captured video Looks pretty good!

    Stability is very irregular and strange. It seems to pull down too much (>1.667 in.), then ramp down to less (<1.667 in.). The speed variations all cancel each other since we don't see frames continuously rolling down the screen.

    https://drive.google.com/file/d/1p-K...ew?usp=sharing

    I doubt the 3D print material type has any impact on accuracy, more likely that would be printer settings. Commercial prints should be as accurate as possible, or get your money back!

    Are there visible imperfections on the 3D sprocket? Assuming this is an optical sensor, would a smaller "shutter" window help?

    Click image for larger version

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    Using two notched wheels as a way to narrow the timing window (if necessary) without having to create multiple printed versions.

    Does the optical sensor provide feed back to adjust stepper speed or trigger the camera?

    Sorry, these questions are probably answered on earlier posts!



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  • Stan Jelavic
    replied
    Welcome back David. I slowed down as well but still keep it going.

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  • David Brown
    replied
    Hi Stan

    Glad to see this is still moving forward! I've been out of the loop since early June. All my capture equip and film is in boxes and I hope to be up and running by the end of the month.

    I do regret that I now have a lot of reading ahead of me, need to catch up.

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