If the scene was uniform, why would the photon distribution not be uniform. What is the reason for this?
@chrisamez I'm guessing photons are modeled as individual particles that hitting a sensor according to a random process. Given enough light, the number of photons hitting the sensors should all be very close to the mean and not result in much visible noise. I think there might be more variance and noise due to this effect in low light scenarios?
The poisson distribution is used to model discrete events that take place in a chunk of time (e.g, the number of cars passed by a location at a certain time). I guess that's why it's used to model photons arriving during a particular exposure at a particular pixel, even if the scene is completely uniform.
I'm having trouble actually finding a good image demonstrating the effect of high vs low photon shot noise. Is this actually a problem that matters in practice?