I really need to take a picture...
I figured out why I was cleaning the image sensor when I took a picture of a clear sky. When I was correcting it, there was something strange in the picture, so I took out the filter and took out the lens.
There was dust on the image sensor...
I turned it on so that when I turn off the power, the shutter curtain comes down to prevent dust from entering, but this is not a good thing. As the shutter moves, it seems to be attracting dust to the image sensor... I guess I need to check it periodically... ㅠㅠㅠ
Still, I tried my best to take pictures. thank you