Why Bayer-pattern and not 3CCD?

Bob Burman · January 14, 2005

It seems that all the upcoming/prototype digital cinematography cameras utilize Bayer-pattern chips instead of 3CCD beamsplitter system (Panavision Genesis seems to be an exception, at least it is "true RGB, not Bayer-pattern"). Now, what exactly is the reason for this? Would a beamsplitter be too big to be fitted within the space limited by the flange focal depth of a PL-mount lens (as Dalsa Origin, Arri D-20 and Kinetta are all PL-mount, while Panavision Genesis is not), or what?

-Bob

John Sprung · January 14, 2005

It seems that all the upcoming/prototype digital cinematography cameras utilize Bayer-pattern chips instead of 3CCD beamsplitter system (Panavision Genesis seems to be an exception, at least it is "true RGB, not Bayer-pattern"). Now, what exactly is the reason for this? Would a beamsplitter be too big to be fitted within the space limited by the flange focal depth of a PL-mount lens (as Dalsa Origin, Arri D-20 and Kinetta are all PL-mount, while Panavision Genesis is not), or what?

-Bob

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The Lockheed-Martin "Blue Herring" camera is a three chip design. Chip size appears to be closer to 65/70 than 35mm. Each chip is 12 Megapixels. The camera last I saw it was a bit smaller than a mini-Cooper.

3CCD is pretty much the same idea and has the same problems as three strip Technicolor. The prism block puts substantial constraints on lens design, it has to be where many film lenses have their back element.

I'm not sure what "true RGB" means. Genesis is a single chip camera with colored filters for each pixel on the chip, just like the others. The only difference is that the arrangement of those pixels is something other than the specific pattern that Bryce Bayer used. Panavision is saying absolutely nothing about what that pattern is, so I suspect there may be some cleverness applied there. As for mounts, a single chip puts no constraints at all on what you can use. Kinetta will make one with any mount you want.

From what I've seen from Genesis and D-20, there' good stuff coming soon.

-- J.S.

Bob Burman · January 15, 2005

I'm not sure what "true RGB" means. Genesis is a single chip camera with colored filters for each pixel on the chip, just like the others. The only difference is that the arrangement of those pixels is something other than the specific pattern that Bryce Bayer used. Panavision is saying absolutely nothing about what that pattern is, so I suspect there may be some cleverness applied there. As for mounts, a single chip puts no constraints at all on what you can use. Kinetta will make one with any mount you want.

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Interesting. I wonder how they achieve the proclaimed 1600 ASA sensitivity with subtractive filtering? Can't imagine the sensor alone would somehow be that much superior to, say, Dalsa's production model, which is billed as 400 ASA.

From what I've seen from Genesis and D-20, there' good stuff coming soon.

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Indeed they are, though I'm definitely a Kinetta fan :lol:.

-Bob

Balazs Rozsa · January 15, 2005

Interesting. I wonder how they achieve the proclaimed 1600 ASA sensitivity with subtractive filtering? Can't imagine the sensor alone would somehow be that much superior to, say, Dalsa's production model, which is billed as 400 ASA.
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I think the difference comes from the fact that Dalsa specifies its ASA sensitivity for 8 megapixels while the Genesis is specified for 2 megapixels. When the sensor sizes are about the same.

Balazs

John Sprung · January 18, 2005

Genesis is specified for 2 megapixels.
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Doesn't Panavision say it's 12.4 megapixels?

-- J.S.

Balazs Rozsa · January 19, 2005

Yes, the Genesis CCD has 12.4 Mpixels, but the camera output is only 2 Mpixels. The Dalsa gives you 8 Mpixels.

Balazs

John Sprung · January 20, 2005

Genesis also lets you take the raw data out via fiber, like the Dalsa.

-- J.S.

Michael Most · January 20, 2005

Genesis also lets you take the raw data out via fiber, like the Dalsa.

Really? Are you sure about that? I've never seen this documented in any of the press releases or product info sheets, and I've never had it told to me by anyone at Panavision. As far as I know, the fiber link is for remote camera control and a monitoring feed, much like the Telecast. The only output format(s) I've ever been told about are the HD single and dual link feeds, not data. Besides, since Panavision claims it doesn't use a standard Bayer pattern, they would likely have to provide some documentation on how to interpret the raw data for demosaic operations - something I'm not sure they really want to do.

John Sprung · January 20, 2005

You might ask Nolan, but I think that's what he said at CineGear last summer.

-- J.S.

Mike Brennan · January 21, 2005

You might ask Nolan, but I think that's what he said at CineGear last summer.
-- J.S.

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In London Nolan said outputs were limited to 1920x1080 444.

Wonder if the Genesis aslo suffers from the cosmike effect?

Mike Brennan

Michael Most · January 21, 2005

You might ask Nolan, but I think that's what he said at CineGear last summer.

I did. Both he and John G. told me that it was 4:4:4 dual link HD only (coded to log format), with various downconversions also available - but no data, certainly no raw data.