Bob Smith wrote: >> If you too can't grasp the principle that photons are converted to >> electrons >> proportionate to the intensity of light, then what can I say? > > That's true, but as I understand it, the analog to digital conversion > is not achieved by counting electrons or photons and that's the crux of > our disagreement. Well maybe I didn't express myself too well, however, you're absolutely correct. In a previous post I thought I had made it clear that the stored electrons were read out as voltages?
> If it we did simply count electrons or photons, then > there'd be no need for an a/d convertor. Correct. > This would simply be a purely > digital device and we'd be capturing numbers at the sensor. I don't > profess to be an expert in the intricacies of sensor workings but its > my understanding that we are measuring an analogue signal produced by > the sensors response to light. Yes! > The more electrons produced, the > stronger the signal, but we aren't literally counting electrons. No we're not, well not exactly. I believe the device creates a voltage on the basis of how many electrons it receives. More or less electrons represent subject brightness's and hence voltages proportionately and that is the message I have been trying to communicate! > I'd > be happy to be shown otherwise. I'm curious about how this stuff works > and its why I participate in threads like this. I assume the strength > of current produced by a given cell changes based on the amount of > light hitting it. Exactly. > In the a/d conversion the highest number available > it assigned to the maximum signal. Bit depth determines how big that > number is and thus how many potential definable steps there are between > the lowest and highest measurable signal. > As someone else suggested > its just the sampling rate. It doesn't change the endpoints of the > analog signal only the precision with which it's sampled. Yes I agree, however, there are definitely more brightness levels, as reflected from the subject, recorded more accurately in a higher, rather than lower, bit-depth device. Best regards, David Kay =============================================================== GO TO http://www.prodig.org for ~ GUIDELINES ~ un/SUBSCRIBING ~ ITEMS for SALE
