Still trying to turn things around. The sensor is simply a photocell. The brighter the light hitting it the higher the voltage output. Visualize analog as curves, digital as steps. Don't get them crossed in your mind if you want to understand what is going on. All the talk about sensors like they are photon counters is pretty counter-productive also, as they definitely are not. It is not like they have a capacity of x photons, but that at a certain point the out put voltage cannot go any higher even if the light is brighter. If you have ever used an old fashioned light meter with a swinging needle, think of a sensor as an super tiny array of them. The ADC converts the voltage into a digital signal with the voltage as a binary number. At this point we are still dealing with the output of a single pixel, the next step is integrating all those signals that is where it gets complicated.
-- graywolf http://www.graywolfphoto.com http://webpages.charter.net/graywolf "Idiot Proof" <==> "Expert Proof" ----------------------------------- Jim King wrote: >> Lets back up a bit here. You have a sensor that has an analog out put. >> You send that output to an analog to digital converter. The converter >> produces an 8, or 10, or 12, or in this case 22 bit digital >> representation of the analog signal. Then that digital >> representation is >> processed digitally. Note that the analog signal does not change. The >> only difference is that the higher bit rates produce a more accurate >> representation of the analog signal. There is no magic here, just >> technology. >> >> Rephrasing that, the analog signal is simply broken up into more >> digital >> pieces, nothing is added to it. > > But the analog signal output is not a smooth curve; it is a stepped > voltage representing the capture of from 0 to about 50,000 > electrons. Sampling at 22 bits will simply give a number of similar > outputs for each step where the voltage is the same. The benefit > will come from averaging these to reduce noise. At least that is how > I envision it... > > Regards, Jim > -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net
