Found an old (actually late 70s) TV camera and did my own mod. Removed most of its guts. Removed the lens on the picamera and mounted the camera module on the lens of this monster. Writes videos to an external USB card reader. It is fully programmable so I can make timelapse, stop-motion and stuff.
Since the cost of a quality raspberry pi sound card is a little too expensive, I decided not to use this for daily shooting, instead I’ll use an external audio recorder with a clapperboard etc.
Runs on a Li-Po battery and can be used as long as 2 hr with 1500 mAh capacity. The old analogue iris mechanism was replaced with a mechanical one which can be seen in the upper part of the lens right integrated on the handle.
I’ve used many of the camera’s original switches and interfaces to control the pi over GPIOs.
Thinking of replacing the CRT viewfinder with an LCD screen which is on its way from china. Focusing with the onboard CRT is really hard. I’ll update as the new screen is mounted. (This modification is done, I’ll update soon)
One of the hardest part on the software side of matters was to make sure there are no dropped frames in the output. I’ve tried many methods to detect dropped frames without much success. Picamera firmware reports minus infinity integer occasionally as DTS and even getting hold of a good timestamp information was not possible at the time. Finally I’m rather convinced that picamera will not drop frames as long as the media write speed is sufficient. Haven’t tested it for long-time recording and a separate audio track but I’ll report the results as soon as I do.
As a final note, since the pi’s image sensor is so small the image output compared to a 35mm film, corresponds to about 120-130mm lens. Happily a wide angle adapter that fits the 57mm filter diameter is also on its way, which will widen the output to 60mm. (wider lens atapter get very pricy very quickly) (This modification is also done and I’ll update soon)
To summarize, this was a fun and challenging process and I’m rather impressed with the results. I’ll post any when I have time to shoot something meaningful.