Thanks for the kind words, everyone. The response to our Time Filter has been awesome. We're working quickly to get these placed where you can rent them, and we also are working with some people for system demonstrations.
We certainly understand that this is a very new and unusual product, so we're doing our best to help match the needs of artists with our technology. If there's something you'd like to know about the system, we're very happy to answer questions.
Folks here have noted the drawbacks of the system: light loss and price. This is a first-generation product. When we initially had the idea for a temporal antialiasing filter, nobody could tell us with any certainty if there would be any market for such a thing. We've found that there most definitely is, and now that some real cinematographers are getting their hands on it (rather than our engineering staff, who are well meaning but not pros) the results are even more spectacular.
The primary goal of the Time Filter is to correct temporal antialiasing (our website explains the details of this), but a side-effect is that it also corrects rolling shutter. Frankly, the rolling shutter in the RED ONE we use hasn't ever bothered me all that much, and it wasn't a design goal to fix it, but it does. We added in a normal 180-degree shutter into the filter control so that you can use it to correct rolling shutter without using the temporal antialiasing curve. The cameras that would most benefit from rolling shutter correction are DSLRs, and unfortunately we cannot synchronize with them.
We are planning more advanced integration with the EPIC, which has some nice synchronization options for over- and under-cranking.
So thank you again, everyone. Everyone we met at Cine Gear was great, and it was a blast.
Tony Davis (the guy in the white lab coat...not my normal outfit.)
cool stuff! thanks for sharing. could be quite useful...
Can you shoot and post a few test movs or avi movies (some format we can advance through one frame at a time) with camera flashguns, and emergency strobes? Would be great if it solved/reduced the one artifact that can be a deal killer when shooting with rolling shutter digital cameras compared with film.
A question - would this also reduce light flicker from out of phase lighting? I can only imagine it would.
The Time Filter shutter drops to zero response around 40 Hz, and stays there all the way up to infinite frequency. So there's no dialing it in or sweeping it around. It just kills all these offending frequencies and their harmonics and they stay dead.
Wow, that was a really long answer to say, yeah, it fixes that.
Quote: [A frequent follow up question is: "Will the Time Filter work with my DSLR, like the Canon 5D Mark II, etc." We are very sorry to say that it won't right now. We need some sort of capability to synchronize with the camera's frame acquisition, and these cameras simply don't provide any way to do that (yet.) We are also excited about the future of these less expensive, lightweight cameras, and would love to be able to provide a solution for them. Our search for an answer continues.]
There might be several simple ways to sync your optical shutter to any HDSLR.
1) You can put an induction coil near the sensor and pick up the readout frequency.
2) You can put a small resistance between the battery terminal and the camera to produce a voltage, there should be some variability of the power use on the shooting frequency that can be amplified and run through a filter.
3) You can pick up EMI/RFI coming from the camera that varies with the shooting frame rate that can be amplified and filtered.
4) Solder onto some point in the camera circuits that gives a signal related to the frame rate.
5) There might be some frame rate ripple on a plug-in-power microphone bias(?)
6) Likewise if there is a headphone output, those may have frame rate ripple in them as well.
7) Stick a adhesive foil strip inside the lens mount area, or on the outside of the camera and pick up the frame rate by capacitive coupling.
8) Is there a relationship between the HDMI or other monitor output VHz and the sensor fps, if so you may be able to genlock after adjustment for that ratio if they use the same crystal clock in the camera(?)...
So it may just be as simple as putting a pickup on the outside of the camera to find its shooting frequency, then do a PLL to a "jam sync" in the crystal of your control box.
You will need a phase control to time the optical shutter to the start of the readout.
Quote: [By the way, the Time Filter has many modes of operation, one of which is to create a simple 180 degree shutter. If you set your camera to 360 degrees, then the Time Filter to 180 degrees, it will totally eliminate rolling shutter without applying the antialiasing filter if you don't want that for a particular shot. Of course, in antialiasing mode, rolling shutter artifacts are eliminated also.]
For cameras with small VBLANK to readout ratios, your optical shutter should not "totally eliminate rolling shutter" it will put a fade on the slope, which is a reduction of noticeably but not an elimination of the skew, you should re-word your faq. The skew is blurred, not totally removed (when using the "360" degree bell curve (where total light pass equals 180 exposure, if you have it half the time black then its a 180 bell curve with about 90 degree peak), rather than a 1 degree global strobe which is too fast for your shutter anyway(?)). The bell curve graph on the site shows that minimum transmission of the LCD filter is not zero, so there would be less than total extinction.
Quote: [360-degree shutter (the normal configuration with the Time Filter)]
I don't think there are any cameras with 360 degree shutter since the reset and read out lines in the sensor are not the same, so at most you get something like 1 line less than total making the maximum angle a bit smaller than 360, as 359.x?
An electro-mechanical version of this type of filter would have no "light loss" because the two pola filters would not be needed. It would be hard to wip-pan though with a large spinning filter... (the idea of these filters is to cut the light by one stop anyway, what I am talking about is the loss in addition to the one stop loss). I had this idea some years ago in several variations, PLZT filters of that time had some diffraction issues so the newer LCD give less "fog" to the results.
One problem I have noticed with 3D LCD shutter glasses is that when dark the density is somewhat un-even. I wonder what the density variation is for your filter over its area at max density. For longer lenses such un-even density would not be a major issue, but for wide angle lenses the crossed pola filters may not be even center to edge? Do anti-rattle filter clamps in the matte box frames cause issues with the liquid crystals, as usually pressure of such can show up as rainbows or un-even density? How do very cold or hot conditions affect the liquid crystals density and switching?
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