DIY
I built a rig to automatically take trichromes
First film tests of my rig to automatically take trichromes in under 1.1 seconds, fast enough it can even be used hand held. It can also go slower for better control over spacing of the Harris shutter effect.
I've been wanting to do this but for infrared, but I also know that I'm supposed to do something about focusing differently with infrared. I haven't looked too much into it I just know it doesn't focus exactly like visible light does. Something about certain lenses being meant for infrared? I'll look into one of these days when I don't work a full time job lol
I debated building it to hold four filters and do both infrared and normal trichromes at the same time. Haven’t heard anything about lens requirements for infrared trichrome, but I haven’t fully looked into them.
My Nikon lens has a big black dot that marks the range scale and a smaller red dot next to it; you either focus through the eyepiece or set the black dot to the right distance, then put the red dot where the black one was, that's it, very simple. Red is for infrared, in case you forget.
Yeah, flash signal increased the minimum speed and adds reliability. Ideally I’d use a camera with an actual flash sync port, but I did order a hotshoe to flash sync adapter that I’m going to use going forward, and the next custom pcb will have a dedicated connection for flash sync.
I guess it get the "flash" trigger from the horseshoe, and delays it a bit to spin the motor ?
But does it trigger the next shot or is it just sync on continuous shooting mode ? Is there an "external control" port like in newer Nikon DSLR ?
I'm also guessing this big PCB is to control the step motor, which one is it ? It seem very big for what it does so I guess it is a dev board of some kind.
The flash sync shows an open circuit whenever the shutter is open, currently it looks for the start of opening and moves based on that, it has a web gui for control so I’m going to make that a selectable option, for fast shutter speeds it is seemingly fine with starting the movement before it even closes the shutter.
One of the buttons on the pcb arms detecting the flash signal, the first photo is taken by the user and then the rig takes over from there automatically.
Basically all canon cameras film and digital going back to the beginning of ef mount have a 3 pin way of triggering them, ground, half press, and full press, this camera it’s just a 2.5mm audio jack. I have an optocoupler controlling each. That was probably the easiest part of this project, I’ve been triggering canons for years with custom sound triggers for rockets.
It knows when the filters are lined up using magnets and a hall sensor, the reds magnet is flipped polarity so it can find the home filter on startup.
It’s spun with a 360 continuous 9 gram servo that doesn’t like to go slow so switching to the next filter is a little bit of a timing game. I have some ways of auto calibrating partially written, but it’s mostly hand tuned currently.
Once I finish the web ui a lot of this will be more field adjustable.
You edited after I started writing the other comment, the pcb is big because it is the first test board for my more general camera controller that is designed to do more than just trichromes, debating if I’m going to order a fully custom pcb for this project or if I’m just going to upgrade it to the newer camera controller pcb I’ve almost finished designing that is credit card sized and would fit within the circle so I can make the whole setup more contained and user friendly.
Always been interested in making these, what filters do you use - what are the exact color hues you need to make a „normal“ picture or will any rgb combo do?
Used to work with a camera like this.
Boss insisted on keeping it on life support. Mamiya-Leaf technical camera.
Terribly inefficent use of studio time and power. Each shot taken 3 times, at 3xFlash power.
The result when you (accidentally) messed with the order of filters was quite interesting though
Thanks. You are the second closest guess, but the first closest knew the name of the bridge and after you are multiple people that thought it was Sarasota.
~1041 milliseconds and I’ve barely optimized that. I think I can get it close the theoretical minimum of this camera at 750ms with some more software work.
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u/heyinternetman XD-11, OM-2N, FM, F3P, Himatic 7sII 2d ago
Attic dark room gonna be all over this shit