Aiming for a low cost but high quality way of copying from super 8 cine film to a modern digital format.
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JPEG Image - 1.67 MB - 10/15/2021 at 11:19
Up to this point everything has been held together with bits of tape and the force of gravity. Rather than explain how I put this together in detail, I'll post some pictures. Essentially it was a matter of screwing the projector to a board to which I attached a cardboard screen and a wooden mount for a mobile 'phone, ensuring everything is in the same place each time I come to capture a reel of film.
Up to now I have been running the camera without any synchronisation to the projector, then manually removing duplicates and blurred frames. This is both tedious and time-consuming!
I have now obtained a cheap Bluetooth AB-Shutter control. I prised it apart with a knife to get to the push-button solder pads. My release has two buttons, one for Android and one for iOS. In practice either button triggers my Android mobile, so I just attached wires to the most convenient.
Once that was done I soldered those wires to some stiff household mains wire. A number of similar projects use a magnet and reed switch to sense frame advance. My cheaper and simpler approach is to use some conductive copper tape on the main pulley and arrange my two wires to be shorted across it once per rotation - aluminium foil would probably work just as well.
The video below shows how it works. I wanted to show how the Bluetooth shutter control flashed for each contact, but since it would only do that whilst paired with my smartphone, I ended up with a series of very short videos!
In operation it works very well, triggering the camera just after the claw has finished pulling down the frame, although I'll admit the timing was more luck than judgement.
The photos below show my experimental set-up. It's simply a gutted projector with a slower motor and a cooler LED lamp. The lamp still gets hot, so is cooled by a fan. Its wide beam is also masked off by a piece of foil. A smaller LED would probably be a much better solution, but I'm using what I had available.
There's a book propped up as a screen and a gorillapod stand for my camera-phone to photograph the frames as they go by.
I'd like to mount this in a more solid manner, with some enclosure around the screen so I can operate the system in the daytime. The fan needs to be moved to allow for a bigger take-up spool and I need to be able to plug in a power cable for my 'phone whilst capturing - at the moment the USB socket rests on the table. Other additions would include a shutter release switch to synchronise the projector and camera and some way (VNC, miracast?) of viewing the screen remotely.
Super 8 only has a frame rate of 18fps, so there's a visible judder to the movement. In order to smooth the motion I attempted to apply some frame interpolation using RIFE ( https://colab.research.google.com/github/HeylonNHP/RIFE-Colab/blob/main/RIFE_Colab.ipynb ) . The frame rate here was doubled to 36fps.
Whilst the camera movement looked smoother it also looked less natural. The process also introduced some strange looking visual artifacts. Maybe this would have worked better with cleaner input frames. There are also a number of settings to adjust in RIFE.
For my second attempt at scanning, I increased the camera resolution from 1920x2560 pixels to 2448x3264. The resulting capture was not as good. Increasing the resolution increased the amount of visible noise on the pictures and they looked a bit overexposed too. I fixed the focal length, but left the exposure settings on auto. I'm using Open Camera on an LG G7 ThinQ.
I still have no sync between my camera and projector, so I had to manually remove blurred frames and duplicates.
This time I sorted out the keystoning by running the photos through ImageMagick and using the perspective transform to re-map the corners of the projection to the corners of a 1440x1080 rectangle. In this case the command was as below.
mogrify -distort Perspective '540,424 0,0 3140,388, 1440,0 680,2290 0,1080 2930,2370 1440,1080' *.jpg
I compiled the frames into a movie using FFMPEG, like this -
ffmpeg -framerate 18 -pattern_type glob -i '*.jpg' -c:v libx264 -pix_fmt yuv420p -vf crop=1440:1080:0:0 out2.mp4
My final result was less distorted, but otherwise inferior to my initial attempt
Here's my first attempt at a capture. I'm driving my projector with an old motor from a video recorder via some gears that came out of a flatbed scanner. My light source is a 50W LED which I've masked off with some foil. This projects onto a piece of card which I photograph with my mobile 'phone. As yet there's no sync between the projector an the camera - it just takes a shot every three seconds, which is close to the projector's frame rate. I used FFMPEG to combine the frames and came up with the file below. There are a few jumps where the camera moves, and horrendous keystoning - but I think it has potential
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