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CCD, the larger they are, more SPDs or larger?


Guest Daniel J. Ashley-Smith

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Guest Daniel J. Ashley-Smith

I?ve just bought a book by Michael Freeman, on digital photography.

 

Looking at the CCD section, he states that in order to get a higher res, you need more or larger CCD's. Why not just have one big CCD? When cameras have 3, is there 1 CCD dedicated for each colour or something? :unsure:

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Guest Daniel J. Ashley-Smith

And I suppose colour fringing is when the spd's are not separated properly and mix?

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You got it, when a camera has 3 CCD's, each one is dedicated to a single color. Rather than using multiple frequency CCD's, you have instead higher-sensitivity B&W CCD's with a color filter in front of them, much like how Technicolor film worked. B&W CCD's mind you have more sensitivity than color ones. The end result is a more detailed color image.

 

New CCD's have more unusual concepts, like multiple-layer of color information. Each layer of the board has sensors designed for different frequencys of light. A 3CCD for cheaper. This takes advantage of the fact that different light wavelengths penetrate silicon differently. Only 1 company I know of uses this technology, and only for still cameras. 3CCD's still have a huge leap in terms of quality and performance over single-chip CCD's.

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Guest Daniel J. Ashley-Smith

Silicon photo diodes, which were used as light meters through the lens but now their job is to actually capture the light.

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  • Premium Member

Hi,

 

Okay, but they do generally detect a lot more than one photon!

 

And yes, there's one for every pixel. Yes, that's a lot. They lose a lot in manufacturing due to defects - and it's accepted that most CCDs have defects which are mapped out in the electronics.

 

You may have encountered the irritating dead pixel situation with LCD monitors.

 

Phil

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