What is the noise when Nikon D90 is turned on?

In your case, the automatic dust removal function of the camera is to dust the CMOS chip, which is normal. But if you can hear the sound, I will ask. It is said that the camera can't hear the sound when it is dusted. I suggest you send it to customer service for testing to see if there is any problem with the dust removal system. The dust removal system prompts that the dust can be removed when it is used up. No dust removal is needed for startup and shutdown!

Introduction to CMOS

CMOS, known as complementary metal oxide semiconductor in Chinese, is an important chip in computer system, which holds the most basic data of system startup. The manufacturing technology of CMOS is no different from that of general computer chips, mainly using semiconductors made of silicon and germanium, so that semiconductors with N (charged) and P (charged) energy levels are stored on CMOS, and the currents generated by these two complementary effects can be recorded and interpreted as images by processing chips. Later, it was found that CMOS can also be used as an image sensor in digital photography after processing, and CMOS sensors can be subdivided into passive pixel sensors and active pixel sensors.

Cmos chip

Landlord, you must adjust the settings when taking pictures, otherwise sometimes you can't adjust the sensitivity. I suggest you have a good check to see if there is anything wrong with the settings.

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