tufty
New Member
So, I have a love of old glass, and particularly old cine cameras. I've been in love with 8mm and super-8 since the end of the '80s, and have a few - well, too many - cameras and projectors lying about. And for quite a while, I've had this desire to "digitalise" myself a camera or 2. Originally, I was looking at one of the old Sony point & shoots, but they're a bugger to get running without the lens block attached, so the project stalled. But more recently, action cameras have got good enough and cheap enough to be usable, and they don't have any of that lens power gubbins to deal with. Plus, the sensors are about the same size as an 8mm frame. It's almost like it was meant to be.
So, I have a Yi 4k, and it's going into an Bolex C8. It's a non-reflex camera with a 2 lens turret, the mechanism's bolloxed so I have absolutely no qualms about gutting it totally. This should be a reasonably easy install, tear out almost all of the mechanism, make up a way of mounting the sensor in the film plane, about the only relatively complicated thing is going to be keeping the original trigger mechanism. I'm not totally interested in doing stop motion or using it for photography generally - it's gonna be 4k video only - so I think I can hook up a microswitch that triggers once on depressing the trigger, and again on releasing, in order to use it to trigger recording whilst the trigger is held *like it should be*.
Here it is :
But I already have the next project in mind. I've got a line on a partially working Beaulieu MR8 at a very affordable price (I'm not going to gut my working TR8, the turret is a nice-to-have but the lenses are all D-mount so I can still use its glass if I want to); this is a reflex camera, which complicates things a bit because I 100% want to keep the viewfinder working. This means fixing and keeping the mechanical shutter, and triggering an image capture for every frame. Shouldn't be too hard to set up a signal at the correct point during the shutter cycle, but it means I need a camera which can be externally triggered. I was looking at the Y4k+, because worst case is to capture a raw full-sensor image every frame and then do the conversion to video stream outside the camera when you've finished shooting. Best case is that I can actually hack the firmware to do what I want directly in camera. I'm pretty good at ARM assembly, and reasonably good at getting reference documentation from manufacturers. Seems the 4k+ uses ThreadX as its RTOS part, I've done some threadx work in the past so if I can manage to pull the firmware apart I might be able to modify the timelapse stuff to use an external hardware trigger rather than a timer. From what I can see, the timelapse stuff is entirely internal to the RTOS and not done by triggering from the Linux side.
So, anyone done anything with external triggering?
Alternatively, I was looking at the DJI O4 air, which would be much, much easier to graft into a camera, but probably hasn't had as many people poking into its guts - I'd still be trying to do something it's not intended for and I haven't really looked into it enough to see how accessible the hardware is. So if anyone can say "do that", or "don't do that" with some degree of certainty, I'd be very thankful.
There's also the issue that if I'm keeping the shutter, I'm certainly keeping the wind mechanism, which means it would be nice to keep the original advance speeds as well. 12 / 18 / 24 / 48 and 64 fps, but the shutter speeds aren't the apocryphal "fps * 2", IIRC it's 1/50 at 18fps or something like that but I'd need to check. If I can get 3 GPIOs, I can do this from the linux side I think, otherwise I'll have to graft in a little microcontroller as well.
My TR8 looks like this (although the eyecup has seen better days), the MR8 is basically the same but without the 3 lens turret. They're gorgeous cameras.
So, I have a Yi 4k, and it's going into an Bolex C8. It's a non-reflex camera with a 2 lens turret, the mechanism's bolloxed so I have absolutely no qualms about gutting it totally. This should be a reasonably easy install, tear out almost all of the mechanism, make up a way of mounting the sensor in the film plane, about the only relatively complicated thing is going to be keeping the original trigger mechanism. I'm not totally interested in doing stop motion or using it for photography generally - it's gonna be 4k video only - so I think I can hook up a microswitch that triggers once on depressing the trigger, and again on releasing, in order to use it to trigger recording whilst the trigger is held *like it should be*.
Here it is :
But I already have the next project in mind. I've got a line on a partially working Beaulieu MR8 at a very affordable price (I'm not going to gut my working TR8, the turret is a nice-to-have but the lenses are all D-mount so I can still use its glass if I want to); this is a reflex camera, which complicates things a bit because I 100% want to keep the viewfinder working. This means fixing and keeping the mechanical shutter, and triggering an image capture for every frame. Shouldn't be too hard to set up a signal at the correct point during the shutter cycle, but it means I need a camera which can be externally triggered. I was looking at the Y4k+, because worst case is to capture a raw full-sensor image every frame and then do the conversion to video stream outside the camera when you've finished shooting. Best case is that I can actually hack the firmware to do what I want directly in camera. I'm pretty good at ARM assembly, and reasonably good at getting reference documentation from manufacturers. Seems the 4k+ uses ThreadX as its RTOS part, I've done some threadx work in the past so if I can manage to pull the firmware apart I might be able to modify the timelapse stuff to use an external hardware trigger rather than a timer. From what I can see, the timelapse stuff is entirely internal to the RTOS and not done by triggering from the Linux side.
So, anyone done anything with external triggering?
Alternatively, I was looking at the DJI O4 air, which would be much, much easier to graft into a camera, but probably hasn't had as many people poking into its guts - I'd still be trying to do something it's not intended for and I haven't really looked into it enough to see how accessible the hardware is. So if anyone can say "do that", or "don't do that" with some degree of certainty, I'd be very thankful.
There's also the issue that if I'm keeping the shutter, I'm certainly keeping the wind mechanism, which means it would be nice to keep the original advance speeds as well. 12 / 18 / 24 / 48 and 64 fps, but the shutter speeds aren't the apocryphal "fps * 2", IIRC it's 1/50 at 18fps or something like that but I'd need to check. If I can get 3 GPIOs, I can do this from the linux side I think, otherwise I'll have to graft in a little microcontroller as well.
My TR8 looks like this (although the eyecup has seen better days), the MR8 is basically the same but without the 3 lens turret. They're gorgeous cameras.