It's fine to buy a second-hand camera, but don't let it end up running out, KEE friends, because there is a problem with the camera sensor. How do you check the camera sensor?
1. Look at the smoothness of the camera body
2. Turn on the camera power, open the rear cup cover on the camera body
3. Set to clean sensor manually, the shutter will open and the sensor can be seen clearly. This is a safe way to view the sensor directly without burning the sensor pixels.
4. Check the sensor is visible in bright light. If mold is present, it will look stained or stringy.
Source : https://rayalaptop.com/
5. Turn off the camera power and turn it on again. Deactivate manual sensor clean mode so that the shutter is closed.
6. Set the shutter speed to bulb mode, open the rear cup on the camera body, capture a white object such as a wall in bright light conditions. Press the shutter button for a long time to produce a full screen white image.
7. Check the results for black spots by zooming in
8. If there are black spots, you can be sure it's mold, but if there aren't any, congratulations, your camera sensor is clean.
9. This method is used for camera bodies without attaching a lens.