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04-25-2012, 01:13 AM   #286
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* if it can be done as a paid firmware update to the K-01, $200 could be a fair price, so $1000 indeed; not sure it can be done, though; if pentax has to modify the hardware, you easily go to $2000; if I have to make the hardware, it's much more expensive, the target would be <$5000

* the D800 records H.264, and can record 12.7 stops of DR in video mode (using Flaat_13p)
* there's nothing in a codec that limits how much DR you can cram into it; what you have is less brightness values per stop of DR, so banding and macroblocking issues start to become more obvious after grading; with Flaat_13p on the D800, in the midtones, you have 28 brightness values per stop of light
* the solution to this is not another codec, but higher bit depth; H.264 can go up to 4:4:4 14-bit

* I can do a 2x2 binning and encode the resulting 2.5K Bayer pattern in CinemaDNG, that's no problem at all, and in fact should reduce aliasing/moire issues (with binning, I'm not skipping anything, I'm averaging) (if the sensor readuot is slow and it has to be a mixture of line skipping and binning, then yes, aliasing/moire can appear, but smart debayering should avoid these issues; I'm pretty sure Adobe and plug-in makers would take care of this)

* what I need most right now is someone who has written a driver for linux (any driver, I just want his skills, not the driver)

04-25-2012, 03:14 AM   #287
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Didn't know it could record 14bit information, wonder what kind of impact that has on encoding.

What i'm trying to say is that it might be better to match the sensor to what can be done.
You can throw in the 24mp sony sensor but if you end up skipping half of it you would be better off with the larger pixels of 16mp sensor and skip less.
04-25-2012, 04:39 AM   #288
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if using smaller pixels has a downside (e.g. in terms of DR or noise), then yes, you want your sensor to match what you're recording

but if you have a great sensor to start with (like that on the K-01), then binning is fine: DR is there, low light performance is there, you're not losing much (actually it's not easy to find a low-mpix APS-C sensor that matches the performance of these sony sensors)

the alternative would be the cmosis CMV12000: CMOS global shutter, APS-C, 4K, 10 stops of DR in standard mode, 15 stops with dual readout mode (which I'm sure must have some drawbacks, apart from reducing max fps, which is not a problem because the sensor is extremely fast anyway)
04-25-2012, 09:00 AM   #289
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QuoteOriginally posted by Samuel H Quote
* the solution to this is not another codec, but higher bit depth; H.264 can go up to 4:4:4 14-bit
Though a Bayer pattern sensor would always be inherently limited to 4:2:2, no?

EDIT: THough with pixel binning I guess you could pick and choose to get to something approximating 4:4:4.


Last edited by wheezl; 04-25-2012 at 09:05 AM.
04-25-2012, 10:17 AM   #290
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Samuel was talking about the same size sensor but different pixel count.

12mp APS-C with no line skipping
is better then
24mp APS-C with line skipping

I said nothing more or nothing less.
04-25-2012, 12:17 PM   #291
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I would love a 10-12mp K-01 style camera, that was fully optimized for video. No line skipping, uncompressed recording, or at least uncompressed HMDI out. 30fps at 3K, 60 fps at 1080p, and 120fps at 720p. Tons of control, and so on...

Back to reality.
04-25-2012, 12:46 PM   #292
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@FullertonImages: it looks like you'd love the cmosis CMV12000 CMV12000 image sensor - Cmosis - Imaging and Machine Vision Europe I'm not sure about the DR, though (I fear "double readout" must have some downsides)

@wheezl:
* at full resolution, a Bayer sensor delivers 4:2:0 color (one full piece of color information for every 4 final pixels)
* at half vertical and half horizontal resolution, a Bayer sensor delivers 4:4:4 color (one full piece of color information for every final pixel)
* at the Alexa ratio (2.8K bayer for 2K final), a Bayer sensor delivers 4:2:2 color (one full piece of color information for every 2 final pixels)
04-25-2012, 01:14 PM   #293
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QuoteOriginally posted by Samuel H Quote
@FullertonImages: it looks like you'd love the cmosis CMV12000 CMV12000 image sensor - Cmosis - Imaging and Machine Vision Europe I'm not sure about the DR, though (I fear "double readout" must have some downsides)
CMV12000 offers a dynamic range of 60dB, extendable to 90dB through several HDR (high dynamic range) operation modes.

60db = 19.9 stops

04-25-2012, 02:43 PM   #294
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I made that mistake too, the correct calculation is here:
Open Source Digital Cinema Camera based on Elphel - Page 3

those 60dB are in terms of power
1000000:1 in power = 1000:1 in voltage --> 10 stops

and 90 dB --> 15 stops, but it uses the HDR mode, which they call "dual exposure" and "dual readout"
that dual readout can be like in the scmos chip (the one that the BMC seems to use) (the chip has two different readout logic circuits, and can use both at the same time) or like in the RED EPIC (in HDRx mode, there's a first 1/50s exposure, then a short 1/800 exposure to preserve highlight detail)
if it's the former, I'd love to use this chip; if it's the latter, I'd avoid it, 10 stops is too little DR in standard mode, and HDRx is good for some situations but troublesome for others
the problem is that I don't know which kind it is: there's very little information about the cmv12000 online, it's not even featured at cmosis' web page, even though the announcement was a long time ago, and to my knowledge there are no products using it yet...

Last edited by Samuel H; 04-26-2012 at 12:50 AM.
04-26-2012, 04:19 AM   #295
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Ah okay, yeah 10stops is to little...

btw have you looked at CCD offerings?
04-26-2012, 04:51 AM   #296
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I like the CCD look for some things (motion looks better) but not for others (light streaks are even worse than rolling shutter)

I haven't looked into CCD options anyway; if I can't get the sony sensors, and the cmosis dual readout mode has big drawbacks, I may have to

it has to be aps-c or bigger, and with 13 or more stops of DR, so it's not easy in any case...
04-26-2012, 06:14 AM   #297
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fairchild have a couple, one of the 4k support binning from the shelves but no idea what the refresh rate is of these sensors.

this the one with binning
http://www.fairchildimaging.com/documents/CCD486DataSheetRevCMarch2010.pdf
The pixels in the horizontal registers are twice the size of the photosites to allow vertical charge binning, and a summing well is also provided to support horizontal charge binning. The array can be read out normally at 4k(H) x 4k(V) full resolution, as a 4k(H) x 2k(V), or 2k(H) x 2k(V). The horizontal shift registers are bi-directional so that the image frame may be read out through a single, or two amplifiers per serial register.
04-26-2012, 06:32 AM   #298
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wow that thing is HUGE!!
must cost a small fortune...
and I'd have to look at the fps specs

it doesn't need binning at all, actually with a 36x24 crop it would be 2.4K, which is just about perfect (perhaps on the low side, but not by much)

anyway, I have a lot of work to do before I even start choosing the final sensor...


edit: it seems to need a mechanical shutter; I can't make one

Last edited by Samuel H; 04-26-2012 at 06:49 AM.
04-26-2012, 06:35 AM   #299
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QuoteOriginally posted by D0n Quote
some of the best filmmakers or our time are actually pushing for faster frame rates at the theatres to improve the look of film...
CinemaCon: James Cameron Demos the Future of Cinema at 60 FPS | FirstShowing.net
surprise, surprise, people say it looks like shit (more specifically, like a cheap soap opera)
The Hobbit ... Didn't Look So Good - Movies Preview at IGN
CinemaCon 2012: THE HOBBIT Underwhelms At 48 Frames Per Second| Badass Digest
'The Hobbit' Turns Off Preview Crowd...

for narrative filmmaking 24p and 2D is the way to go
04-26-2012, 08:24 AM   #300
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QuoteOriginally posted by Samuel H Quote
surprise, surprise, people say it looks like shit (more specifically, like a cheap soap opera)
The Hobbit ... Didn't Look So Good - Movies Preview at IGN
CinemaCon 2012: THE HOBBIT Underwhelms At 48 Frames Per Second| Badass Digest
'The Hobbit' Turns Off Preview Crowd...

for narrative filmmaking 24p and 2D is the way to go
people are ALWAYS adverse to change.... then once they get used to it, they won't want to change that either when something better comes along....
There is a reason some people get called "Visionaries"....

hell if we listen to all the small minded people, we'd still be watching soundless black and white while an orchestra plays live music...
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