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JVC GY-HD Series Camera Systems
GY-HD 100 & 200 series ProHD HDV camcorders & decks.

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Old March 30th, 2005, 08:14 AM   #76
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Dominic,

By the numbers, that's right. I'm not sure what those numbers would mean either.

Also, it's a little bit risky to refer to anybody as a "god" in this business...I've been in it long enough to know that there's very few people deserving of hyperbole like that.
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Old April 3rd, 2005, 02:21 PM   #77
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Questions: JVC/Pana Uncompressed/formats/output options, and 35mm SLR adaptor

If the uncompressed output is available in 24/25fps at 10bits 4:4:4 (pre pixel shift, if any) then that would be great. The equipment for do it yourself HD can be largely PC parts, and be "relatively" cheap. Over at dvinfo's Alternative imaging threads, we are working on such cameras (but more DIY cameras) but only one is ready for market so far, and none have three chip. They fool themselves a little over there, in that thinking Bayer is alright because film companies are using single chip HD cameras with Bayer filters (boy I'll get flamed for that one). What they don't realise is that those companies have extra resolution (say 6MP) a lot of expertised, money and time, and lighting, to accurately process Bayer and processing. Still they will probably leave a loot of the HDV cameras for dead (after processing) for a similar price. On the other hand, apparently it is hard to make a high resolution 3 chip prism system that is perfect and gets rid of colour fringing and takes wide aperture lens.


Questions:
Anyway my questions are: what are the specs of this uncompressed output (like what i wrote above) and how is it available (component, HDSDI, Firewire, Hard Disk, the best)? But with the Panasonic camera, what is the actual resolution picked up by the camera? I read over t the MS HD format description that the HD format that it uses supports 10bit, but does it do uncompressed, and what type, and how.

Another question is, what sort of shutter do these things use, rolling, or global. And how do they go on blooming, smearing, moiring etc?


Suggestion SLR Lens converter:
On the detachable bayonet lens, and 35mm SLR lens converter.

I want to point out that one of the things that gives the 35mm lens adaptors film like feeling, is that they reduce the contrast level and probably adjusting the gamma curve (probably making it more like the human eye). Some Density filters try to do the same thing (I forget the company that has them).

Another method, that can reduce DOF (being used) is to get a very large aperture lens (which is not so compatible with image sensors with arrays of microlens light collectors). At extra aperture the DOF is also smaller ;). The image should be brighter also, but a variable filter could be used so you can keep the lens open. So it might be possible to make a reducer lens adaptor to take the image from the SLR lens to the chip size.

With this system, you should be able to achieve much better resolution than a standard 35mm adaptor (no grain) but I don't know about DOF (but how much do you need anyway). You would have to be very careful picking the optics and the calculations (to reduce distortion and aberrations) though.

Another thing the normal adaptors do is soft-focus the image (to reduce hard lines) this could be done in software, but a soft-focus filter would probably be good.

I forgot to mention if you want to do an adaptor, go to the alternative imaging forums at dvinfo to discuss it, I am sure Chris does not want us to discuss it here.


For Laurence, once you apply these things to an uncompressed stream, like I said above, you can see why I am not very worried about using 1/2inch (or 1/3rd inch) chips over at those threads. If you can do everything right (the microlens/prism might be a restriction) the only thing that the bigger chips really has over smaller ones is the smaller Signal to Noise ratio (the adaptor handles everything else).
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Old April 5th, 2005, 04:47 AM   #78
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Wayne - surely the component output can't be "pre pixel shift" for two reasons:

1. Pixel shift is set by physically moving the CCDs, so to get rid of pixel shift one of the CCDs would have to be switched off.

2. since pixel shift increases the output resolution of a number of CCDs (ir the FX1/Z1 960px CCDs can output 1440px) "pre-prixel shift would result in a lower resolution" (about 854x720, lower even than the DVCproHD cams)

I think it likely this camera will have a native 1280x720 CCD like the HD1/HD10 and won't use pixel shift technology anyway.

Do you mean "pre-compression"?
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Old April 5th, 2005, 06:03 AM   #79
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"My thinking here being that if you double all the numbers (which maintains exactly the same ratio), then you end up with 4:2:2 from 2:1:1 - which makes them the same thing, no?!"

The ratio would be the same, but the number '4' indicates that the sampling frequency is 13.5MHz -- so a format that was defined as a '2' baseline would have half the resolution of one with a '4'. That's why when BetaSP is given a digital equivalent it is described as 3:1:1 ... that description acknowledges the maximum luma resolution per scan line is somewhat less than the 720 of digital formats, and the ratio of chroma bandwidth to luma bandwith is indicated in the chroma ratio.

Using this same logic, a format (as yet uninvented) that offered a higher sampling rate across a scan line might be described as 6:2:2 ... we can only hope!

GB
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Old April 5th, 2005, 07:17 AM   #80
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Sorry for the confusion Dylan. What I meant was the native shifted pixels, before they were converted to the higher resolution HD output format. In native, it would be 4:4:4 (though converted to higher res 4:4:4 is good for most people), in the 4:2:0 mode you automatically loose colour information for each pixel. You can also get better results doing the pixel shift stuff yourself sometimes (that's how the native output of the DVX100's camera head is being used to produce HD images on Juan's conversion project). The output might not be taking full advantage of the pixel shift. This makes it a more intensive post production process. All this extra details makes for much better resolution upscaling to feature print.
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