GH1 Stereoscopic Rig Collaboration

ekteTV said:
Maybe David Cole can chime in on this? David, what do you use for monitoring when aligning and shooting 3D with your rig?
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For the GH1, I use a PC laptop with 2 USB analog video digitizers and Stereoscopic Multiplexer from Peter Wimmer. For the GH2s, I use two 5" Lilliput HDMI displays, mounted side-by-side. It's NOT a solution to alignment, but, it helps a little to see both cam's output side-by-side. Unfortunately, I don't think there is an affordable solution out there for 2 discrete HDMI inputs.
 
g.l said:
Just a quick demo to show that a simul-powered GH2 dual rig is capable of excellent sync. T
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Excellent! I've been shooting with a new Scarlet rig, but, gotta tell you... the GH2 w/ Driftwood Quantum patch gives it a run for the money.
 
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David Cole said:
For the GH1, I use a PC laptop with 2 USB analog video digitizers and Stereoscopic Multiplexer from Peter Wimmer. For the GH2s, I use two 5" Lilliput HDMI displays, mounted side-by-side. It's NOT a solution to alignment, but, it helps a little to see both cam's output side-by-side. Unfortunately, I don't think there is an affordable solution out there for 2 discrete HDMI inputs.
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Are you aware of the beamsplitter solution for two monitors? That's exactly what I've nearly completed:

sd1710_351_lp.jpg


The idea is that you overlay the images from both monitors with a beamsplitter, ie. a 50%/50% half-silvered mirror. You can partially look through it and see the 1st monitor (behind), and the 2nd (above) is partially reflected in it, so both images end up being overlayed. You can use this as-is for alignments, but even better is that LCD monitors are already linearly polarized - and the mirror rotates the polarization of the reflected image. So you can just use ordinary linear polarized glasses to see in 3D!

stereopsis-diagram.jpg


Two caveats, 1) the reflected monitor must be able to mirror (reverse) its own image horizontally or vertically. With the GH2 at least (prolly the GH1 too) that is taken care off by just flipping out the LCD - it reverses the image (to give you a mirror image to look at when you're shooting yourself) and also outputs that to the HDMI output.

And 2) the linear rotation of LCD displays differs, so you may have to rotate the filters in the glasses to match (but then the cardboard types are ultra cheap, or you can even buy linear sheets and make your own with better frames). Or you might just luck out and they match. Easy to test: look at a monitor with the glasses - if one eye is fully black and the other clear, the rotation matches. If you have to rotate the glasses ~45deg to get there, then you have to rotate the filters to match.

You can build the whole thing into a box - easiest but bulky - or something collapsible as shown (my choice). I'll post more of mine when I get around to finishing it (maybe in a few weeks).
 
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My partner uses, essentially, a small teleprompter with 2 RED LCDs to do this for his REDONE rig. Works well - but - it's a bit clunky, delicate and pretty sensitive to glare. It's certainly an option for aligning a rig!
 
David Cole said:
Interestingly, no mater how we rig the test hardware, the LEFT camera always proceeds the RIGHT. Unfortunately, these values do not seem to correlate with sync at all. We'll rerun w/ the sync values to share.
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It's quite likely you've already solved this conundrum (I haven't yet read the entire thread...), but if not, may I offer a hypothesis? It is that the discrepancy could be caused by the resistor networks on the left and right side of the switch not being exactly equal.
 
On the Lilliput website there is an autostereoscopic 3D field monitor mentioned but without anything but the name.
No photo, no data-sheet.
That could be interesting for monitoring.
 
sampablokuper said:
It's quite likely you've already solved this conundrum (I haven't yet read the entire thread...), but if not, may I offer a hypothesis? It is that the discrepancy could be caused by the resistor networks on the left and right side of the switch not being exactly equal.
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That's interesting. The camera though has a pretty wide tolerance for the remote's resistance trigger values, they don't need to be exact, just lie in the correct range for each shutter state.
 
I have 2 of them and Arduino Code to start a recording via LANC but I don't have the time to test a 3D rig due to a large show to be recorded coming up.
 
Is your code available? I program AVRs so I could give it a try. They may also need simultaneous powering like the GH's.

EDIT: I see there's code out there.
 
Simultanous power doesn't work via the 12V connector as that one charges the internal battery while operating the camera.
Stoping to interrupt the internal battery doesn't switch on the camera, a button needs to be pressed that can not be pressed via LANC.
 
Can you power the camera without an internal battery installed? And it still needs a 'soft' power-on via button?
 
I can check that on the weekend but I don't think so.
It certainly won't switch on when you apply power without touching the power button. So it doesn't help in synchronously switching them on.
It's a push button, not a switch like with the GHx
 
Please do. OK so the power button is likely on an interrupt that wakes the CPU.

The question is, if frame capture timing works off a free-running timer like on the GH's, is this timer already running as soon as it gets physical power? If not, maybe there's some way to reset it, or maybe a LANC command (worst-case a solder hack on the power button).

I will start a Pocket-specific thread over on Personal-View later (will post link). If anybody has already tried this (David?) please chime in.
 
Actually, maybe just taping down the power button would work. Could you try that at the weekend Marcus? Just hold the power button first (no battery installed), then connect 12V power?
 
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