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This topic comprises 3 pages: 1 2 3
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Author
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Topic: High Frame Rate (HFR) digital cinema
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Mark Ogden
Jedi Master Film Handler
Posts: 943
From: Little Falls, N.J.
Registered: Jun 99
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posted 11-05-2011 12:08 AM
quote: Bobby Henderson
When they're cutting the maximum exposure time in half or less by jumping from 24fps to 48 or 60
There is no exposure “time” in video cameras. Exposure is constant. If the camera is turned on and the lens is open, than the imager is being exposed. The only thing that changes with increased frame rate is the speed at which the rows or columns of photosites are clocked into the transfer register. This has nothing to do with exposure time especially since the individual charge wells only take one to two microseconds to refresh. In some imager design (CMOS mostly) individual rows of pixels can be timed to become light receptive at certain specific intervals, the so called “rolling shutter” system, but this can happen as fast or as slow as you have the processing for without any image degradation or variation in light or f-stop, and the actual refresh rate of the charge well remains the same.
quote: Bobby Henderson
then they're going to be asking a hell of a lot more from the CCDs or CMOS chips in the camera
What more is being asked? There is nothing that is particularly electrically stressful about an increase in frame rate. Nearly all video cameras employ a Peltier element or some other form of thermo-electric cooling on the imager substrate (DSLRs do not, which is why you only get 10 or 12 minutes of video shooting out of them before they overheat. Don’t get me started.). If you are an ENG photographer shooting a low-light crime scene at +12db I suppose that in a manner of speaking you are “asking a lot more” from the imager, but that is a practice that rarely if ever happens in movie/episodic TV production.
quote: Bobby Henderson
Are they going to up the bit rate by 200% or 250% to correspond with those much higher frame rates?
A 12-bit image is a 12-bit image, period, regardless of how many times you are able to produce one. How slow do you think the throughput is on these cameras? The Vision Phantom puts out a 14 bit 1920x1080 image at 1,000 frames per second. Is that enough?
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Carsten Kurz
Film God
Posts: 4340
From: Cologne, NRW, Germany
Registered: Aug 2009
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posted 11-05-2011 08:04 AM
Current Cameras like RED One, Epic, Scarlet, Phantom, etc. can go to hundreds or even thousands of frames per second without a problem.Sure they wouldn't mind being pushed to just 48 instead of 24...
That said - I just returned from holiday from a friend with the latest Panasonic 52" Plasma. The manual was far to complex for him so he left everything on factory defaults. When we were first watching TV from a satellite feed, I immediately recognized the effect of the frame interpolation. It had some interesting, strange quality touch, but at the same time was slightly annoying, at least with the crime movie we were watching. Looked it up in the setup menu, disabled it, fine.
A few days later, we were watching 'Departed' from BluRay. Right into the first dolly shots of Jack Nicholson, I immediately noticed there was something wrong again. I asked my friend wether he had switched frame interpolation back on, but he said he wouldn't even know what I'm talking about. Went into the menu and saw it changed, it had an EXTRA frame interpolation setting for 24p that is only active when 24p content is shown. Disabled it, fine. Back to good old 24p, and it looked like a movie again.
Now, until I have seen High Frame Rate both natively shot AND interpolated side by side, I ask myself wether the soap opera look, or at least the annoying part of it, really comes from high temporal resolution itself, or the interpolation (artifacts). It could be that native 48fps shots look better (more 'normal') than interpolated 48fps.
Besides that, most current TVs and projectors interpolate to much more than double rate. Usually, if at all configurable, 96, 120, or even up to 200 fps. Maybe that is just too much. Maybe 48fps native is a good 'compromise'.
And, again I haven't seen it myself, maybe it makes a huge difference between 2D and 3D. I can really see 3D benefitting from it, but I am not interested in HR for 2D at all. Not missing anything there.
- Carsten
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Carsten Kurz
Film God
Posts: 4340
From: Cologne, NRW, Germany
Registered: Aug 2009
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posted 11-05-2011 09:23 AM
It really is true that blacklevels also bother me lately. SeriesII on small and midsize screens now are so extremely bright in 2D, that the relatively low contrast range of all projectors needs to be paid attention. With 35mm, the 48cd/sqm was not only a minimal requirement, but also a 'limit' because of the more visible flicker at higher brightness.
Now with digital one should not overdo the brightness while just enjoing bright and well light testmaterial.
2D vs 3D lamp brightness adjustment, silver screen, etc., all come into play here.
I have seen 150cd/sqm during a recent installation/setup phase on a 9m screen. The testimages blew me away first, but when I noticed the black level after they switched of the test images with the dowser still open, I was shocked.
- Carsten
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Bobby Henderson
"Ask me about Trajan."
Posts: 10973
From: Lawton, OK, USA
Registered: Apr 2001
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posted 11-05-2011 12:37 PM
quote: Mark Ogden
There is no exposure “time” in video cameras.
A CCD or CMOS chip does not "see" an image in an absolute instant. Latency is an issue. The way you're describing it the imaging chips work absolutely perfectly. In actual practice they do not. This is fact for both digital still cameras and video cameras. When light levels are really great the systems work fine. When the light levels are low the chips start tripping all over themselves, rendering smeary soupy looking stuff. Cranking up the gain works only so well, the trade-off is increased noise, loss of detail and even alteration of color.
quote: Mark Ogden
What more is being asked? There is nothing that is particularly electrically stressful about an increase in frame rate.
Bandwidth is an issue. Raw HD footage uncompressed is rougly 1.4 billion bits per second just at 8 bit level and standard 24 or 30 frame rates. That's too much for a standard single hard disc to eat; RAID is required for storage and playback. If the frame rate is doubled then so are the bandwidth requirements. The same thing goes for upping the color bit depth. Video cameras need to record in as high a color bit depth as possible if the footage is going to be processed to look like film. A deep color image will withstand alterations in post production a lot better than one with a basic color signal.
Cost is also increased. Most Hollywood movies still have digital intermediates, CGI, etc. rendered at only 2K. 4K costs a lot more. So will high frame rate movies. Given the choice between 4K at 24fps and high frame rate movies at 2K I'll choose 4K.
quote: Mark Ogden
If you are an ENG photographer shooting a low-light crime scene at +12db I suppose that in a manner of speaking you are “asking a lot more” from the imager, but that is a practice that rarely if ever happens in movie/episodic TV production.
I've seen plenty of video-sourced Hollywood movies with scenes in low light settings where the imagery looked very sub-par and not at all like film.
quote: Mark Ogden
The Vision Phantom puts out a 14 bit 1920x1080 image at 1,000 frames per second. Is that enough?
And that's way too much for any data storage sysetm in existence to store in raw, uncompressed quality. There's only so many bits you can cram through a data pipe. Data storage systems can drink up store data only so fast. And there's room for only so much.
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Jussi Siponen
Film Handler
Posts: 75
From: Mikkeli, Itä-Suomi, FINLAND
Registered: Jan 2010
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posted 11-15-2011 04:56 PM
Time to poke the HFR hornet's nest some more ![[Razz]](tongue.gif)
Brad obviously doesn't care for the taste of this particular cool-aid, but others seem to be drinking:
quote:
... Douglas Trumbull, aka Doug Trumbull, is a legendary special effects creator/producer/filmmaker who's worked for Stanley Kubrick, Terrence Malick, Ridley Scott and Steven Spielberg. He's now 69 years old but still pushing along, even trying to revolutionize cinema as we know it today, which is exactly what he explains in the interview with Bleeding Cool, while mentioning a space project he wants to make.
While Trumbull has been linked recently to Terrence Malick's Tree of Life (he did the origin of the universe sequences) and the rumored IMAX follow-up, we posted a story in April this year about Trumbull working on his very own 3D high framerate feature film. We know that The Hobbit is shooting at 48FPS and James Cameron demo'd both 48 and 60FPS, but Trumbull says in the interview he's pushing speeds of up to 120FPS. Why not higher? "I don't see right now any visible advantage to go even higher than 120 frames, I think that's about as much as the human eye can absorb." That sounds pretty crazy, I can't even imagine.
Trumbull goes on to say exactly that, that few people have truly seen what this is like. Here's a few quotes:
"I'm shooting films right now at 120fps in 3D and I know that the result is absolutely stunning but very few people on this planet have actually seen that, yet. I have a very challenging process ahead of me to start demonstrating this and doing at least one film that I want to make.
"I have several films lined up but I've got one in particular that would lend itself to this. It's a big space adventure movie. And I've got to make the movie and show it in this process and convince people that there's a very big audience that wants to see this kind of tremendous technological, creative, visual leap forward to much higher quality."
Trumbull explains that if he can achieve something like this, it will be a huge visual step forward, which is kind of what he did with 2001: A Space Odyssey. He explains: "Combining 120 frames and high brightness and gain screens that are very wide and large with a different seating configuration is a huge epic change that will take some time to effect. But I'm working on it." To be frank, this sounds a little too insane to seem real, but maybe he's working on something, despite how long it'll take to actually see. I'm intrigued, and I truly can't imagine what 120FPS is like, I was blown away by 60 at CinemaCon. As for the space adventure, which I'm excited for no matter what, he sheds a bit of hazy light on what it might be about in a follow-up.
FirstShowing.net: Doug Trumbull Wants to Make a 120...
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Carsten Kurz
Film God
Posts: 4340
From: Cologne, NRW, Germany
Registered: Aug 2009
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posted 11-15-2011 08:09 PM
Well I guess it makes a huge difference with the kind of material your presenting. I can imagine that 'classical' IMAX stuff could benefit from it - nature, docs, animation, sports, etc., and probably 3D in general, for simple perceptive reasons.
I mean, all the previous experience with HighFrameRate footage was with rides, etc.
Asside from certain action shots, I can't see it for narrative scenes.
- Carsten
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