What is the symptom that the camera behind the mobile phone is broken? Why does the definition of the camera get worse after enlargement?

Excuse me, is your SLR or card machine? The larger the aperture, the longer the focal length or the farther the background is from the subject, the more blurred it is. In photography, this is called background blur. After enlarging the aperture, the subject is clear, but the background becomes blurred. If you want the background of the subject to be as clear as the head, you can achieve this effect by narrowing the aperture. Magnifying aperture is usually used to shoot portraits and sugary portraits, which can make people clear and clear behind them. So is my mobile phone camera. It's all like this