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Author Topic: Why not a CMOS 645 sensor  (Read 5045 times)
mcfoto
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« on: August 02, 2008, 08:08:06 PM »
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Hi
I know James wants a clean iso 800 with MFD. I remember using the Leaf Vealo 6 digital back which was 6 mp. I preferred it over the 16 mp Kodax back at the time. Faster & less noise. I am sure Sony or Canon could build a 645 CMOS chip. I think the new Canon 1DsMKIII chip is amazing for a 24x36 chip & look at what Nikon is doing with there new 12 mp chip ( iso 25000 ). It might even bring the price down? I find the difference between CMOS & CCD is the same as color neg vrs tranny.
Denis
« Last Edit: August 03, 2008, 02:08:03 AM by mcfoto » Logged

Denis Montalbetti
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tho_mas
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« Reply #1 on: August 02, 2008, 09:10:06 PM »
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I know James wants a clean iso 800 with MFD. I remember using the Leaf Vealo 6 digital back which was 6 mp. I preferred it over the 16 mp Kodax back at the time. Faster & less noise. I am sure Sony or Canon could build a 645 CMOS chip. I think the new Canon 1DsMKIII chip is amazing for a 24x36 chip & look at what Canon is doing with there new 12 mp chip ( iso 25000 ). It might even bring the price down? I find the difference between CMOS & CCD is the same as color neg vrs tranny.
CCDs have backside illumination and CMOS have not. This might be one of the advantages of the CCDs with regard to IQ. But Sony starts to produce CMOS with backside illumination. But just for smaller chips. The production of bigger chips is much to expensive by now.

http://techon.nikkeibp.co.jp/english/NEWS_...0080612/153222/
http://scr3.golem.de/?d=0806/Sony_CMOS_BSI&a=60326&s=1
http://scr3.golem.de/?d=0806/Sony_CMOS_BSI&a=60326&s=2


http://www.cnet.com.au/digitalcameras/came...39285504,00.htm
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In this rarefied atmosphere, where camera equipment costs tens of thousands of dollars, CCD still rules the roost. In part that's because a camera doesn't need to shoot at high speeds, and in part because consuming a lot of battery power isn't a top-level problem.

"For those customers, the first, second, and third priority is the image quality the sensor provides," DeLucca said.

Phase One, which uses Kodak CCD sensors, agrees. "For the 50- to 80-megapixel sensors on the horizon, we still feel the CCD will be the best way forward," said PhaseOne Chief Executive Henrik Hakonsson. "We are carefully monitoring CMOS all the time, but for the customers we working for we have not found the quality we're looking for."
« Last Edit: August 02, 2008, 09:12:16 PM by tho_mas » Logged
michaelnotar
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« Reply #2 on: August 03, 2008, 01:18:47 AM »
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"CCDs have backside illumination and CMOS have not. This might be one of the advantages of the CCDs with regard to IQ. But Sony starts to produce CMOS with backside illumination. But just for smaller chips. The production of bigger chips is much to expensive by now."

what is backside allumination on the chip and why is it important, what does it do?

and i havent heard anything on the 12MP canon chip and iso 25000, any further reading you can suggest? the only thing i have heard of at this point is a 12mp rebel but i cant imagine that going that high and IQ wouldnt be great with the 1.6x chip.
« Last Edit: August 03, 2008, 01:20:48 AM by michaelnotar » Logged
tho_mas
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« Reply #3 on: August 03, 2008, 05:03:21 AM »
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what is backside allumination on the chip and why is it important, what does it do?
click on the first link in my posting above  

http://www.dalsa.com/markets/ccd_vs_cmos.asp
->
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In a CMOS sensor, each pixel has its own charge-to-voltage conversion, and the sensor often also includes amplifiers, noise-correction, and digitization circuits, so that the chip outputs digital bits. These other functions increase the design complexity and reduce the area available for light capture. With each pixel doing its own conversion, uniformity is lower.

http://www.dalsa.com/shared/content/Photon...S_Litwiller.pdf
http://www.dalsa.com/shared/content/pdfs/C...willer_2005.pdf
« Last Edit: August 03, 2008, 05:07:18 AM by tho_mas » Logged
Khun_K
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« Reply #4 on: August 03, 2008, 09:43:10 AM »
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I thought years ago Leaf offered the C-Most back, not sure it is still available but it is using CMOS sensor.
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BJL
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« Reply #5 on: August 06, 2008, 04:40:42 PM »
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I thought years ago Leaf offered the C-Most back, not sure it is still available but it is using CMOS sensor.
[a href=\"index.php?act=findpost&pid=212772\"][{POST_SNAPBACK}][/a]
Yes, but that sensor was only of the 24x36mm format of 35mm, and 6.6MP. What is more, the sensor design was by Fill Factory, so it was probably a cousin of the FillFactory CMOS sensor of the Kodak 14/N several years later. If so, not a promising solution for low noise at high ISO speeds in MF.

It seems that the DMF sensor market is too small for any other sensor producer to get involved. But Kodak is promoting its custom CMOS sensor capabilities including large stitched sensors ...
« Last Edit: August 06, 2008, 04:41:08 PM by BJL » Logged
shutay
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« Reply #6 on: August 11, 2008, 02:35:59 AM »
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and i havent heard anything on the 12MP canon chip and iso 25000, any further reading you can suggest? the only thing i have heard of at this point is a 12mp rebel but i cant imagine that going that high and IQ wouldnt be great with the 1.6x chip.
[a href=\"index.php?act=findpost&pid=212693\"][{POST_SNAPBACK}][/a]

If you read Denis' post again, he was referring not to Canon, but to the new Nikon 12mp 35mm full frame sensor in their D3 and D700 models which can shoot a very respectable ISO 25,600. I don't know if you are referring to whether there has been any response from Canon from Nikon's ISO 25,600 challenge.

To me, 2008 seems to be the year of the full frame sensor, for both 35mm and medium format. Hasselblad, PhaseOne, Leaf all announcing wider than 48mm sensors, Canon went full frame years ago, Nikon has gone full frame, Sony will be going full frame as well this year and Leica with rumours of a larger than 35mm sensor. I wonder if this means that manufacturers' ability to make large chips has radically improved? I.e., improved yield, even if the volume has not increased much? That would still improve their cost and profitability.
« Last Edit: August 11, 2008, 02:37:29 AM by shutay » Logged
Panopeeper
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« Reply #7 on: August 11, 2008, 10:03:01 AM »
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The Nikon D3 is a great camera; however, some of the above references to it are misguided.

1. the high ISO capability is due primarilly to the large sensels. Those, who are expecting the successor with twice as many pixels but the same "pixel quality" will have some sobering moments,

2. the D3 does not have ISO 25,600, not even 12,800. The highest ISO is 6400; the rest is "pushing the exposure", useful only for JPEG shooters.
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Gabor
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« Reply #8 on: August 11, 2008, 05:55:51 PM »
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1. the high ISO capability is due primarilly to the large sensels. Those, who are expecting the successor with twice as many pixels but the same "pixel quality" will have some sobering moments,
[a href=\"index.php?act=findpost&pid=214415\"][{POST_SNAPBACK}][/a]

The only hope being that Nikon has made significant progress in the one year period of time that ellapsed between the D3 and D3x developements.

Although I would personnally have preferred a total focus on low ISO image quality, my gess is that the d3x will be very decent up to at least ISO1600. I would expect it to be better than the D3 between ISO 100 and 800, and less that 1/3 stop behind the D3 at ISO 1600 a given print size in terms of actual image detail. The gap is likely to widen at ISO3200, but this is not an area where MF shooters would go anyway.

This is what the 1ds3/d3 comparison tend to show, and the d3x will be more than one year newer than the 1ds3, which means that Nikon will have pushed the bar again.

Cheers,
Bernard
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A few images online here!
Panopeeper
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« Reply #9 on: August 11, 2008, 07:45:01 PM »
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This is what the 1ds3/d3 comparison tend to show, and the d3x will be more than one year newer than the 1ds3, which means that Nikon will have pushed the bar again

Long live the competition!
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Gabor
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