I am thinking do noise caused by ISO considered some sort of aliasing? If so, do noise increase in this case caused by reduction in sampling frequency or increasing in signal frequency? Also since the sampling / signal rate is affected by multiple things when taking a picture, does that also mean that the noise caused by ISO can be alleviated by other means like reducing shutter speed or open up aperture?
Staffjamesfong1
@geos98 Higher ISO comes with higher noise, but this kind of artifact is unrelated to aliasing. In a high-quality camera, the higher noise is only caused by photon shot noise.
jonathanlu31
For smartphones with night sight that can take images in the dark, do they employ higher ISOs with extra tricks to reduce noise, or do they use a separate mechanism altogether?
aceschen
@jonathanlu31 I think one trick that smartphone night mode cameras use is to take long exposures, ie significantly increase the shutter speed. By increasing the shutter speed, more light can be taken in without increasing the ISO as much, therefore reducing noise. (at least this is my best memory of what I learned in photo decal, reminded by the exposure triangle: https://photographypro.com/wp-content/uploads/2017/11/exposure-triangle-diagram2.png)
I am thinking do noise caused by ISO considered some sort of aliasing? If so, do noise increase in this case caused by reduction in sampling frequency or increasing in signal frequency? Also since the sampling / signal rate is affected by multiple things when taking a picture, does that also mean that the noise caused by ISO can be alleviated by other means like reducing shutter speed or open up aperture?
@geos98 Higher ISO comes with higher noise, but this kind of artifact is unrelated to aliasing. In a high-quality camera, the higher noise is only caused by photon shot noise.
For smartphones with night sight that can take images in the dark, do they employ higher ISOs with extra tricks to reduce noise, or do they use a separate mechanism altogether?
@jonathanlu31 I think one trick that smartphone night mode cameras use is to take long exposures, ie significantly increase the shutter speed. By increasing the shutter speed, more light can be taken in without increasing the ISO as much, therefore reducing noise. (at least this is my best memory of what I learned in photo decal, reminded by the exposure triangle: https://photographypro.com/wp-content/uploads/2017/11/exposure-triangle-diagram2.png)