On 16/10/06, graywolf <[EMAIL PROTECTED]> wrote: > Well there is the fact that your analog signal from the sensor is for > one color pixel from the sensor. Then several pixels are analysed, > combined according to that analysis, and written out as 4 3-color > pixels. And that is just for a RAW image. It is not a simple convert one > pixel to x bits operation. Is 22 bits over kill for that? I do not know.
A RAW file remains in as a Bayer filter matrix recording of luminance under colour filtration and the sensor latitude can be practically wholly encompassed using a 12 bit data depth. RAW conversion utilizes these 12 bit per pixel values in combinations dependent on the complexity of the demosaicing algorithms. I don't know of any demosaicing algorithm currently that's written to address data files of more than 16bits/pixel. The precision of the ADC is excessive, why they settled on 22 bits I don't know, but in any case I guess it's always better to have more data than required as it's easier to discard unwanted information than to try to reclaim that which was not recorded :-) > I suspect that they are using a 22 bit ADC simply because that is what > was available. But if they are eventually planing 16 bits per pixel > output, a 22 bit ADC is not over kill at all. A point to consider is > that with modern IC's that ADC is not just an ADC it is most likely a > computer chip as well. The chip supposedly selected contains an ADC which incorporates timing generators for the clocking pulses required by the sensor as well as various types of digital level adjustment. 22 bits on the ADC is overkill as is 16 bits /colour channel RAW files as the characteristics of the sensor simply don't warrant it in the case of the K10D. > The point I am trying to make here is I think the analysis of this that > folks are making here on the list are way over simplified. That's always going to be the case (other than the designers of the chip) but the realities are indisputable. It's just completely over engineered. I guess an analogy could be putting a honking great 7L V8 in a standard mini chassis, yes I'm sure it can be done but obviously the full output of the motor could never effectively be transferred to the road. -- Rob Studdert HURSTVILLE AUSTRALIA Tel +61-2-9554-4110 UTC(GMT) +10 Hours [EMAIL PROTECTED] http://home.swiftdsl.com.au/~distudio//publications/ Pentax user since 1986, PDMLer since 1998 -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net
