What do you mean by photographic noise? What do you mean by photographic noise?

1. Simply put, it is the "graininess" in the photo. There are colors and monochrome, and that is noise. So why do photos sometimes have a lot of noise?

2, related to photosensitive elements. The photosensitive element, namely cmos, is the "heart" of the camera and determines the imaging quality. It will also affect the image quality and noise. Generally speaking, the larger the area of cmos, the less noise, which explains that the photos of mobile phones generally look more noisy, but the SLR is less. It is also a SLR, and a full-frame camera has less noise than an APS-C camera. It has something to do with sensitivity. Sensitivity is iso, which is a well-known and familiar truth. The basic knowledge of photography has long told everyone that the higher the iso, the more noise there will be, and with the improvement of iso, the more obvious the noise will be. It's related to exposure time. If you don't use the slow door very much, you may not even notice this problem. If the camera is exposed for a long time, generally more than 20 or 30 seconds, or when the camera is exposed together with the B door, it is easy to cause more noise due to the heat dissipation problem of the fuselage itself. However, unless you shoot a specific subject, such as the starry sky, you rarely use a particularly long exposure. It's related to the later period. It mainly includes two situations. One is that you took underexposed photos in the early stage, and there will be a lot of noise when you need to brighten them up to normal exposure value in the later stage. On the other hand, after many times of color matching, the picture also produces unnecessary noise.