The occurance of this symptom is due to the characteristic of the camera that is built in to this machine.
The PCG-C1VM series adopts an ultra-compact CCD camera.
Due to the lighting conditions at the time of recording, the image recorded with this camera may look sharper in the center part than at the border sometimes. This is the characteristic of the notebook and is not a failure.
The improvement of the overall resolution permits more light to the center part than to the borders. This differentiates the sharpness between these 2 areas and gives an impression that the four corners are slightly darker.