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Epic sensor pixel count

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John HeagyEpic sensor pixel count
by on Apr 22, 2010 at 9:08:40 pm

Did a quick search and found no mention of the actual pixel count of the Epic 5K sensor. If memory serves the Red One was 4.5K@4K the Alexa is 3.5K@2K. One would hope for 6K@5K for the Epic.

John


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Noah KadnerRe: Epic sensor pixel count
by on Apr 22, 2010 at 9:45:46 pm

Pretty sure that data is somewhere on RED's site for the really curious. :)

Noah

Check out my book: RED: The Ultimate Guide to Using the Revolutionary Camera!
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John HeagyRe: Epic sensor pixel count
by on Apr 23, 2010 at 1:19:36 am

[Noah Kadner] "Pretty sure that data is somewhere on RED's site for the really curious. :) "

Like a spec sheet?... http://epic.red.com/downloads/RED_SPEC_SHEET_EPIC.pdf

Alas, style over substance...

Curious minds want to know.





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Noah KadnerRe: Epic sensor pixel count
by on Apr 23, 2010 at 1:39:06 am

Or perhaps:

http://en.wikipedia.org/wiki/Red_Digital_Cinema_Camera_Company#Epic

Noah

Check out my book: RED: The Ultimate Guide to Using the Revolutionary Camera!
Unlock the secrets of 24p, HD and Final Cut Studio with Call Box Training. Featuring the Sony EX1 Guidebook, Panasonic HVX200, Canon EOS 5D Mark II and Canon 7D.
Watch Formosa- My indie movie shot with the SDX900 and finished with Final Cut Studio.


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John HeagyRe: Epic sensor pixel count
by on Apr 23, 2010 at 4:41:35 pm

Hmmm... perhaps, but I suspect this info is from 2 years ago since it includes the 28K "Unobtainium" sensor specs. It may still be correct, but I'd certainly like to see official specs on Red's site. Nice find though...

The Wiki lists the Epic sensor at 5120, that's only 600 more pixels than the 4520 of the old sensor. One would expect 1000 more pixels to claim an increase from 4K to 5K. Of course you can only shrink the photo sites so much before they start loosing their light gathering ability.

Given this info was not readily available, what are people's thoughts on the sensor resolution? Arri certainly took the high road with a 3.5K sensor outputting 2K. P+S Teknik's 16mm digital mag claims 1920 with only a 2048 sensor which falls even shorter. http://www.pstechnik.de/en/digitalfilm-16sr-magazine.php

Considering the Red One's original sensor is 4.5K@4K the Epic's 5.1K@5K does not maintain the same debayer margin. This assumes the full 4.5K is exposed in the Red One and debayered to 4K, and the Epic Wiki specs are correct.

John



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Noah KadnerRe: Epic sensor pixel count
by on Apr 23, 2010 at 5:16:37 pm

These are questions I'd be asking over at REDuser. It's kind of a guess on this board where we focus more on the workflow.

Noah

Check out my book: RED: The Ultimate Guide to Using the Revolutionary Camera!
Unlock the secrets of 24p, HD and Final Cut Studio with Call Box Training. Featuring the Sony EX1 Guidebook, Panasonic HVX200, Canon EOS 5D Mark II and Canon 7D.
Watch Formosa- My indie movie shot with the SDX900 and finished with Final Cut Studio.


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Graeme NattressRe: Epic sensor pixel count
by on Apr 23, 2010 at 6:29:12 pm

Original RED One sensor has an active area of 4520x2540. In normal 16:9 shooting of 4096x2304, the rest of the image is used for "look around". We added a 4.5k wide mode of 4480x1920.

The M-X sensor has the same 5.4micron pixel pitch as the original in the RED One, but the active area is larger, out to 5120x2560.

Now onto measured resolution: All sensors generally have more pixels than their measured resolution, as otherwise there would be too much aliasing occurring as you try to get too much detail onto the sensor, and that extra detail "folds back" to appear as lower frequencies in the image, thus corrupting the image with moire.

So with the RED we record, say, 4096 across, but the measured resolution is somewhere between 78% and 85% of that depending on lens, M or M-X, and level of REDCODE compression. This is measured on a totally un-sharpened image, because on any camera you can always add post sharpening, and most video cameras have such sharpening built into their signal processing if you want it or not. Even top end 1080p HD cameras don't measure a true 1080p because they filter to avoid aliasing, or allow through too much aliasing that actually corrupts the fine detail they're trying to record.

Although Arri advertise a 3.5k sensor, the active area for HD is only 2.8k, the rest being "look around". Now, as far as I know, nobody has published resolution test charts for the Arri, so we don't know the exact details of how it performs. Obviously, they should measure > 2k on their RAW recording, otherwise there'd be little point in them doing RAW recording over 1080p HD-SDI output, although if they properly optically filter and depending on the algorithms use, them may find the RAW resolution is closer to 2.25k, and therefor see little benefit from the RAW. This, of course, depends on the quality of the in-camera downsample and demosaic, which may be improved by offline algorithms.

Graeme

- http://www.nattress.com - Film Effects and Standards Conversion for FCP


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John HeagyRe: Epic sensor pixel count
by on Apr 23, 2010 at 9:44:51 pm

Very interesting! A few questions...

[Graeme Nattress] "he rest of the image is used for "look around"."

Just so I'm clear... "look around" is image outside what is captured, but is seen in the viewfinder? I thought this was something digital cameras could not afford to do.

[Graeme Nattress] "The M-X sensor has the same 5.4micron pixel pitch as the original in the RED One, but the active area is larger, out to 5120x2560."

So the new sensor does not add any pixels to a given 35mm exposure area. One would need a lens to expose beyond what was exposed previous - resulting in a wider field of view - not a pixel/resolution increase.

[Graeme Nattress] "Although Arri advertise a 3.5k sensor, the active area for HD is only 2.8k, the rest being "look around"."

Still a significant over sampling which is always good, and honestly I thought necessary, in a Bayer sensor.

Thanks
John Heagy



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Graeme NattressRe: Epic sensor pixel count
by on Apr 25, 2010 at 12:44:37 am

Well, we afford it :-) One of the key things we heard people liked in optical viewfinders was to be able to see things come into shot before they got recorded, so we included that by making the sensor bigger than needed.

Most lenses have no bother illuminating the 5k, but you should check for vignetting.

Ideally, all sensor arrangements would have more pixels than the resolution you wish to perceive in the finished image. Half the problem with the "video look" is that HD (and SD too, but for a while there were SD cameras that did oversample and did make for very nice images) cameras only have the minimum sensor pixels necessary. For them to get a good resolution, they must also have significant aliasing which leads to over-sharp, un-natural edges. Or they properly optically filter and use electronic sharpening. Both lead to a video look.

Graeme



- http://www.nattress.com - Film Effects and Standards Conversion for FCP


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Nelson GoforthRe: Epic sensor pixel count
by on Jul 21, 2010 at 9:04:22 pm

Graeme,

You posted that the 'active' area of the M-X sensor is (or will be in the Epic) 5120x2560 pixels. But is that the recorded image size, or the full size of the sensor with look-around, etc.? The ratio didn't work out to 16:9, so I'm wondering.

And even though the M-X sensor is in upgraded Red One cameras, I'm assuming that the effective sensor size for 4K 16:9 is still the same as it was for the original sensor. Am I correct?

Thank you, as always, for providing solid information here and on RedUser.

Nelson Goforth


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Graeme NattressRe: Epic sensor pixel count
by on Jul 21, 2010 at 9:06:41 pm

5120x2560 is max recordable area. The sensor has the same 5.4micron pixel size as the original Mysterium - it just got some more pixels added to it.

Graeme

- http://www.nattress.com - Film Effects and Standards Conversion for FCP


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