a) Try to set a high phone size or video quality: go to the “Camera” app->touch the settings icon at the top left of the corner on the screen->touch “Photo size”, select “4:3 - HIGH PIXEL”->touch “Video quality”->select high quality(4K>1080P>720P) . As for the choice of Frame rate, 60fps is better than 30fps, but requires more storage.
b) Photo quality is likely to be affected by poor light levels at night. If you shoot in low light situations, the photo favours the dark tones with small amount of image noise or shading. Because the camera will increase the ISO value to lift the shadow areas, image noise will also be amplified and consequently you will feel that the photo is fuzzy.
1) It is recommended that you find a well-lit view or environment to take a photo or have a video chat.
2) Turn your flash on when using rear camera.
c) Try to reset the camera settings: go to the “Camera” app->touch the settings icon at the top left corner of the screen->touch “Reset settings”->“RESET”