- Jan 16, 2017
any physics majors on here?
not here but what I understand is that photons quanta on dark parts of scenes are way scarcer than on the bright parts so the noise is inherent in nature (think of geiger meter random sounds away from a radiation source vs constant white noise hum when close, as in the movies) and not affected much more by all the other noise sources of the camera’s imaging systemany physics majors on here?
To avoid giving somebody the idea that "some photons are noise and some aren't", might be better to emphasize that the "noise" is simply the random variation between adjacent collection sites, which tend to average out as predicted by the distribution model... this means not only over the duration of one continuous collection, but even if you average the pixels from two images taken at completely different times (given an equivalent signal). This is why you can stack shots for noise reduction.They capture a Poisson distribution and the variation or noise is proportional to the square root of the captured number. So in this 10 photon case 3.1 of the 10 photons are noise which is about 1/3rd. Capturing 100 photons 10 or 1/10th would be noise.
You are correct. I was confused thinking more photons captured at the top end increased dynamic range while they are actually captured at the same illumination level. Only at the bottom end is two stops less illumination required to capture the same number of photons and give the same signal to noise ratio.
Machi has touched on it, and it is explained further about 30 minutes into the video link I posted, should you not want to view the whole presentation, in the "Shot noise" portion.Mark73, What is this "Buckets of Rain" thingy? Am learning and very naive re digital stuff.
I mentioned the reflection as I recently experienced a blue area on a "night moon grab." Only time I noticed and not sure what it was. Maybe a bucket of rain?
Keep it simple, which I know is not so easily done!