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Arri HD image technology


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#1 Jane Margo

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Posted 01 April 2009 - 11:05 AM

Hi, I think this is my first post. I have some really off the wall questions concerning the cmos imager and using a mechanical shutter. I don't know how Arri has done it but from what I have researched, shutters are needed for still images but there is a fail when it comes to shooting video on still camera. So then the cameras are designed to make the shutter inoperative during video mode.

This is my question. don't laugh. Does anyone here know what the possibilites are of devising and arrangement with cmos imager into a mirror reflex film camera such as Eclair, CP16 or any in that class. I know, why would you want to do that? My first thought was, I see issues stated all the time about DOF and the new HD video cameras and third party lens adapters for 35mm lens. I have to question why does it have to be this way? I get excellent DOF and beautiful images from my CP16 with an Ang. 12-120. My thoughts are, why wouldn't be possible to have everything as in the Arri D20/21 in a cinematography camera only in a Super 16 version?

Basically, can a cmos imager work on a mirror reflex optical path arrangement using Super16mm lenses? Of course, this would be a new invention. I'm no expert in this technology but I do have a bench with all kinds of cannibalized cameras and parts and I do engineer some of my own parts and accessories. Ok, I know this was long winded. Hope someone can enlighten me.
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#2 Adrian Sierkowski

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Posted 01 April 2009 - 12:36 PM

From what I'm told Aaton is working with something similar to this for the Penelope camera. You can do it. Just mounting an imager on a camera magazine exactly where the film would line up with the gate, and keep the electronics/recording/power in the mag itself. Then you can go from film to HD whenever you'd like.
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#3 Phil Rhodes

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Posted 01 April 2009 - 12:36 PM

The possibility of a digital back for existing motion picture cameras has been widely discussed. The only problems with it are sorting out the mechanical design, such that you can get a CMOS or CCD imager up against the pressure plate of the camera and make a magazine-shaped device with all the supporting technology in it.

If you wanted to homebrew such a thing, you'd want to find yourself an old magazine, a single-chip video camera with a 2/3" sensor, and a way to sync the mirror shutter on the film camera to the video camera's output, then make with the JB Weld, nuts, bolts, and carefully-bent pieces of aluminium. You'd probably have to have a new groundglass made up with any alterations to the framing.

Strikes me as fairly doable, but I can't immediately think of the right sort of video camera to dismember. You could look at machine vision cameras, but you'd have to figure out some way of recording it that would fit in the mag.

P
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#4 David Rakoczy

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Posted 01 April 2009 - 12:47 PM

DigiMags for the Arri SR Series would be great!
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#5 Adrian Sierkowski

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Posted 01 April 2009 - 12:50 PM

And if you can build 'em i'm sure David and I would buy em!
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#6 Adrian Sierkowski

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Posted 01 April 2009 - 12:54 PM

If it's a CO-AX mag, on the take up side, just fill 'er up with SSDs and on the Feed side keep all the electronics. Then everyone will be "familiar' with the tech ;)
Give us a few ports for fast transferr out, maybe a gigabit ethernet and wham bam thank you ma'am ;)
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#7 John Brawley

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Posted 01 April 2009 - 07:32 PM

DigiMags for the Arri SR Series would be great!


It does exist.

It was built in 2002.

http://www.urbanfox....19joedunton.htm

It was a prototype only but never took off. JDC got bought by panavision UK i think....

Aaton are working on a 6K digimag for their new 35mm penelope camera.

jb
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#8 David Rakoczy

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Posted 01 April 2009 - 08:21 PM

Thanks John.. I hope ARRI builds one.. but not for $45k! :o They won't sell many at that price...
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#9 John Brawley

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Posted 01 April 2009 - 08:23 PM

Thanks John.. I hope ARRI builds one.. but not for $45k! :o They won't sell many at that price...


And that was in 2002 for HD-SDI out only (no data) !

Still. you don't need to buy any more gear right ??

I doubt Arri will ever do it. Why would they cannibalise their D21 brand ? Phil !? Why don't you knock something together ???

jb
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#10 Phil Rhodes

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Posted 01 April 2009 - 10:49 PM

Phil !? Why don't you knock something together ???


Time. Money.

Lack of access to a broken SR1.

P
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#11 Jane Margo

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Posted 01 April 2009 - 10:54 PM

Thank you everyone for your wonderful replies. They do give encouragement. I'm going to test a few things with what I have. I have a cannibalized Frezzi LW16 with a dog leg viewfinder on a Ang 9.5-85mm lens. Getting the imager properly with the lens is my main goal. I'm not worried about the shutter at this time until I can look further into a mirror reflex. Just the idea of having a true optical viewfinder is enough to get me excited about this for now. Then I'll go from there.
Thanks again
Jane
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#12 David Auner aac

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Posted 02 April 2009 - 02:48 AM

Strikes me as fairly doable, but I can't immediately think of the right sort of video camera to dismember. You could look at machine vision cameras, but you'd have to figure out some way of recording it that would fit in the mag.


Hi Phil,

check this out. Toshiba IK-HD1. Maybe something like that would work. It's a pitty it's 1080i only. But this one is 1080p! 1-chip CMOS IK-HR1D

Still doesn't solve the recording thing though.

Cheers, Dave
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#13 Phil Rhodes

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Posted 02 April 2009 - 06:24 AM

check this out. Toshiba IK-HD1. Maybe something like that would work. It's a pitty it's 1080i only. But this one is 1080p! 1-chip CMOS IK-HR1D


The issue there is that it's only a 1/3" imager, which is considerably smaller than the super-16 frame. Really you'd want a 2/3" device, which would make things considerably more expensive if you could even find a single chip example.

There are plenty of 3-chip 2/3" miniature cameras but that'd give you unpleasant issues with certain lenses, since film lenses aren't generally set up to drive 3-chip splitters.

P
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#14 David Auner aac

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Posted 02 April 2009 - 07:40 AM

The issue there is that it's only a 1/3" imager, which is considerably smaller than the super-16 frame. Really you'd want a 2/3" device, which would make things considerably more expensive if you could even find a single chip example.


Yes, that's true. I was thinking of some kind of relay optics. Same as in some of the adapters for 2/3" lenses on 1/2" cameras. But then again you'd need a ground glass or the like to get the image off, right? Trouble is, you'd run into the same problems you have with 35mm DOF adapters (grain patterns, vignetting etc.).

Cheers, Dave
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#15 John Sprung

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Posted 02 April 2009 - 12:21 PM

Does anyone here know what the possibilites are of devising and arrangement with cmos imager into a mirror reflex film camera such as Eclair, CP16 or any in that class.


Arri's D-21 and the Dalsa cameras do/did use mirror shutter reflex viewing with big single CMOS/CCD chips.

The problem with making such a thing as a conversion to an existing film camera is that most of the film camera becomes excess baggage. You don't need a big powerful motor or any of the high precision pulldown, registration and sprocket stuff with all the gears, belts, etc. Letting all that expensive stuff sit around wasted would be sort of like hauling a dead cold steam locomotive between a diesel engine and the train.

The cost of the imaging chip and electronics is so large that it makes sense to build them into their own camera. There's no way that this could be an inexpensive accessory.

Mirror shutter won't work on a three chip design, because the glass prism has to be in the same place as the shutter.



-- J.S.
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#16 Jane Margo

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Posted 02 April 2009 - 03:10 PM

Ok, here is something I know. First of all, camera manufactures advertise the chip type (size) There is a difference between the type and the size. A 2/3" cmos chip for example does not have a 2/3" image area. The diagonal dimension of the super16 aperture is approximately 14.54mm. To accomodate that image area you would need a 1-1/8" cmos chip to do the job. I didn't calulate the actual image area... lol but I know that chip would almost perfectly fit the Super16 aperture. The Super35 cmos chip in the Arri's is massively huge. If I am wrong about this, please somebody let me know.
Thanks,
Jane
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#17 John Sprung

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Posted 02 April 2009 - 07:32 PM

The deal on these fractional inch sizes like 1/4" or 2/3" is that they're the legacy of old time glass tube cameras. Those were the diameters of the tubes, the image areas were always smaller. When chips replaced tubes, they kept the same image areas, and they kept on referring to them by the old nominal tube diameters. I know they had 1" tubes, but I've never before heard of 1 1/8".

The same thing happens with plumbing. A half inch water pipe is just a tad less than 7/8" in outside diameter.



-- J.S.
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#18 Jane Margo

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Posted 03 April 2009 - 12:51 PM

You are correct John about following suite with the tube sizes. I maintained one of the broadcast telecine units from RCA. The camera had 4 1 inch tubes. I didn't think there was anything bigger but the chip makers are doing new and innovative stuff for this technolgy we are talking about like the Arri D21. The Super35 chip's image area is that of a 35mm film apeture.

I will try to find where I got the info but I had a chart that showed everything from super8 dimensions, to consumer camcorder 1/4" ccd's to the new breads of Sony cmos applications and all the way up the line. The chart allowed you to go to and film format like Super16. It has the diaganal dimensions as well as H x W and gave reference to what size (type) chip you would need.

I'll return with that link so you can see. Now if the chip even exisits maybe another story. I haven't gotten that far yet. But I have rethought some of this and I wonder, does the chip really have to match the size of the Super16 apeture? Could a condenser lens be installed coupled with the collimer adjustment give the targeted image onto say a 2/3" chip?
Jane
P.S. Does anyone know how to get my profile pic to show up in the forums?


The deal on these fractional inch sizes like 1/4" or 2/3" is that they're the legacy of old time glass tube cameras. Those were the diameters of the tubes, the image areas were always smaller. When chips replaced tubes, they kept the same image areas, and they kept on referring to them by the old nominal tube diameters. I know they had 1" tubes, but I've never before heard of 1 1/8".

The same thing happens with plumbing. A half inch water pipe is just a tad less than 7/8" in outside diameter.



-- J.S.


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#19 John Sprung

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Posted 03 April 2009 - 01:45 PM

... I wonder, does the chip really have to match the size of the Super16 apeture? Could a condenser lens be installed coupled with the collimer adjustment give the targeted image onto say a 2/3" chip?


You could always put a ground glass in the focal plane, and just shoot the image off of it. That's how the 35mm lens to 2/3" camera adapters do it. But again, you don't need to schlep the whole 16mm film camera around to do that.




-- J.S.
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#20 Brian Drysdale

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Posted 03 April 2009 - 02:31 PM

You are correct John about following suite with the tube sizes. I maintained one of the broadcast telecine units from RCA. The camera had 4 1 inch tubes. I didn't think there was anything bigger but the chip makers are doing new and innovative stuff for this technolgy we are talking about like the Arri D21. The Super35 chip's image area is that of a 35mm film apeture.


The EMI 2001 used four 30mm tubes.

http://www.tvcameram...1/emi2001_1.htm

It was still in use by the BBC until 1991. For a large studio camera it was surprisingly compact.
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