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03-21-2008, 05:48 PM   #16
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This is a patent filed in 2006. Obviously, Pentax abandonned this route and teamed up with Samsung soon after.


QuoteOriginally posted by Matjazz Quote
It is an area of photography where sensors still fall behind film considerably.
Ever heard of the Schwarzschild effect? Films are very bad for long-time exposures.

03-21-2008, 07:55 PM   #17
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QuoteOriginally posted by falconeye Quote
This is a patent filed in 2006. Obviously, Pentax abandonned this route and teamed up with Samsung soon after.
I wouldn't be too sure. A patent is just an idea. Getting it to work in real life can take time.

Busiko, please forgive us our skepticism. I think we're all a little wary after seeing so many "patents" for the new technology in the K20
03-21-2008, 08:10 PM   #18
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QuoteOriginally posted by Busiko Quote
(46)....therefore, exposure to light for a long time becomes possible. For example, it is also possible to take an image of a night view beautifully by conducting exposure to light for a long time.
36 pages of diagrams and construction specs dealing w/ angles of incidence and warp specifications and , as far as I found, ONLY that one statement regarding exposure time increases. will admit I didn't read it word for word but found nothing beside that one statement.
Any cooling will improve long exposures... doubt if a passive heatsink or thinner substrate or better air flow would change the properities much. At best this effect is secondary to the real benefit of a curved fields sensor....
03-22-2008, 08:06 AM   #19
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QuoteOriginally posted by jeffkrol Quote
36 pages of diagrams and construction specs dealing w/ angles of incidence and warp specifications and , as far as I found, ONLY that one statement regarding exposure time increases. will admit I didn't read it word for word but found nothing beside that one statement.
Any cooling will improve long exposures... doubt if a passive heatsink or thinner substrate or better air flow would change the properities much. At best this effect is secondary to the real benefit of a curved fields sensor....
I've been called stupid so many a time. Sometimes I deserved it, surely, but you don't expect me to believe that a 36 page document which deals with the description AND method of producing a sensor will need to refer the long exposure quality of it more than once.
It also says on the document that due to the warping compensation effect the peripheral areas of the sensor will gain in image quality, the use of fewer components will make it cheaper to produce, which is a great, great benefit, and also implicit there is the gain over thermal noise produced in the chip which will allow for more signal gain maintaining the signal+noise/noise ratio well controlled permitting higher quality ISO settings to be used. Now if you say that this sensor, Pentax/Hitachi developed, is the very same that Samsung manufactures and is in the K20D body, is a completely different matter and I buy it. Otherwise expect to see, soon, a new DSLR with a much better IQ than the K20D.

Best regards
Rui

03-22-2008, 10:45 AM   #20
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QuoteOriginally posted by Busiko Quote
I've been called stupid so many a time. Sometimes I deserved it, surely, but you don't expect me to believe that a 36 page document which deals with the description AND method of producing a sensor will need to refer the long exposure quality of it more than once.
It also says on the document that due to the warping compensation effect the peripheral areas of the sensor will gain in image quality, the use of fewer components will make it cheaper to produce, which is a great, great benefit, and also implicit there is the gain over thermal noise produced in the chip which will allow for more signal gain maintaining the signal+noise/noise ratio well controlled permitting higher quality ISO settings to be used. Now if you say that this sensor, Pentax/Hitachi developed, is the very same that Samsung manufactures and is in the K20D body, is a completely different matter and I buy it. Otherwise expect to see, soon, a new DSLR with a much better IQ than the K20D.

Best regards
Rui
Not stupid at all.
Now to get an idea of what it means I just need someone to translate this so I can see what the big whoop-de-doo is about:
Since the solid-state image pickup element is bonded to the substrate formed of silicon nitride having a favorable thermal conduction property (having a thermal conductivity of 90 W/mK), heat generated in the solid-state image pickup element can be radiated to the outside via the substrate quickly. When the solid-state image pickup device is used in a camera, therefore, exposure to light for a long time becomes possible. For example, it is also possible to take an image of a night view beautifully by conducting exposure to light for a long time.
90 W/mK vs Pure SI thermal conductivity 1.3 W cm-1°C-1
so we have 90 Watts/Meter Degree K vs 1.3W/Centimeter Degree Celsius
03-22-2008, 02:06 PM   #21
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QuoteOriginally posted by Busiko Quote
Acho que tem de ler novamente...
Rui, sem ofensa, mas tu está sendo um pouco cabeça dura. A parte sobre exposições longas é só uma descrição de como o sensor CMOS funciona.

I read the paper again, and the two parts where it mentions night photography are identical. As far as I know (not much), CMOS sensors already have a silicon nitride or silicon dioxide layer beneath the photodiodes to radiate the heat. The part you mention, which I will copy one more time:

Since the solid-state image pickup element is bonded to the substrate formed of silicon nitride having a favorable thermal conduction property (having a thermal conductivity of 90 W/mK), heat generated in the solid-state image pickup element can be radiated to the outside via the substrate quickly. When the solid-state image pickup device is used in a camera, therefore, exposure to light for a long time becomes possible. For example, it is also possible to take an image of a night view beautifully by conducting exposure to light for a long time.

looks like a description of the way the sensor works, right now, the present ones. Long exposures ARE a possibility in the current sensors, that is not a new feature. Of course improvements are due, I see you're excited at the possibility of longer exposures with less noise/hot pixels, but this document is not about that...

Yet this sensor warping to match the image field is very interesting, thanks for bringing that to light! I hope this becomes available in the near future - that would knock down most of the 4/3s sensor advantages.
03-26-2008, 04:54 PM   #22
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QuoteOriginally posted by clawhammer Quote
I wouldn't be too sure. A patent is just an idea. Getting it to work in real life can take time.
I don't want to be argumentative, but patents generally are far more than just ideas. Countries grant patents (i.e. a period of exclusive ownership and use of an invention) in exchange for what the "teachings" of a patent add to a country's technological information base. Consequently, most countries require clear evidence (via "examples") of reduction of the invention to practice.

You're absolutely right, however, in your comment ("getting it to work in real life") about making an invention a commercial success. An invention may be legally novel (i.e. worthy of a patent), but completely impractical, too costly to commercialize or of such narrow scope it lacks any value. Indeed, relatively few patents - for a host of reasons - are ever commercially exploited. So, the fact that Pentax (or anyone else) holds a patent doesn't mean the invention it represents is utilized commercially.

Has the patent case under discussion actually been granted or is it still a WO application that has been published but not yet issued?

Jer
03-27-2008, 04:39 PM   #23
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QuoteOriginally posted by Sailor Quote
I don't want to be argumentative, but patents generally are far more than just ideas. Countries grant patents (i.e. a period of exclusive ownership and use of an invention) in exchange for what the "teachings" of a patent add to a country's technological information base. Consequently, most countries require clear evidence (via "examples") of reduction of the invention to practice.

You're absolutely right, however, in your comment ("getting it to work in real life") about making an invention a commercial success. An invention may be legally novel (i.e. worthy of a patent), but completely impractical, too costly to commercialize or of such narrow scope it lacks any value. Indeed, relatively few patents - for a host of reasons - are ever commercially exploited. So, the fact that Pentax (or anyone else) holds a patent doesn't mean the invention it represents is utilized commercially.

Has the patent case under discussion actually been granted or is it still a WO application that has been published but not yet issued?

Jer
Thanks Jer for your comments. This has been started as a futuristic exercise regarding sensor technology and its applications.
On the paper Pentax says that peripheral image quality is improved and that the lower component count will make it cheaper to produce. From that it looks very feasible and desirable. So it's up to Pentax to produce it or not. Maybe it's already in the market and I simply ignore it.
It's a 2006 Japan patent for which an application was submitted in the USA last February. The status is:
Docketed New Case - Ready for Examination

Regards,
Rui

03-28-2008, 09:30 AM   #24
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QuoteOriginally posted by Busiko Quote
Sorry Chris. I don't own a K20D nor I've ever read the manual. So I stand corrected by the numbers.

Meanwhile I think someone should alert Pentax and Hitachi because maybe they are wasting their time on such a research and development.
Their document:
PreGrant Publication Database Search Results: AN/pentax AND AN/hitachi in PGPUB Production Database

points at that direction. Overall IQ should benefit from that.
Quote:

[0046](f) Since the solid-state image pickup element is bonded to the substrate formed of silicon nitride having a favorable thermal conduction property (having a thermal conductivity of 90 W/mK), heat generated in the solid-state image pickup element can be radiated to the outside via the substrate quickly. When the solid-state image pickup device is used in a camera, therefore, exposure to light for a long time becomes possible. For example, it is also possible to take an image of a night view beautifully by conducting exposure to light for a long time.

[0047](g) As described in (b), the warp of the light sensing face of the solid-state image pickup element can be made to coincide with or be approximate to the curvature of field. As for the light receiving quantity in the image peripheral part as well, the same light quantity as that in the image center part can be taken in, and a clear image can be obtained. In the color video image, therefore, it becomes possible to unify the color density in the image center and in the image peripheral part.
Unquote.

Sorry for taking your precious time.
Regards
Rui

I think that noise and warping from heat might be part of the reason for this development, but the part you quoted reads more like a development that helps to counter the COS4 light rolloff as you move towards the edges of the image.

I think (Contax?) made a film camera with a curved film plane and a vacuum device to suck the film down to it for the same reason.

I will have to read the entire claim when I have time, but it looks interesting, regardless of the reasons for the development.

Ray
03-28-2008, 09:43 AM   #25
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QuoteOriginally posted by Busiko Quote
With BULB mode the problem remains. Use it and abuse it then tell me.
What are you on about? I've taken 2 minute plus exposure with no problems.
03-28-2008, 02:49 PM   #26
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QuoteOriginally posted by Matjazz Quote
It's a known fact that during long exposures noise builds up because of heat. Leave a camera in bulb mode for long enough and you get a white frame. It is an area of photography where sensors still fall behind film considerably. Just try and make a night photo where stars rotate 15° and leave continuous trail (2h exposure)
15° = 1 hour.
03-28-2008, 02:54 PM   #27
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I happen to know someone who took a 3 hour exposure with his EOS 350D, and apart from the fact that you could tell he needed to clean the sensor, everything was fine and dandy.
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