A blur or dark spot appears on the recorded images.

When you change the lens, even if you are very careful, tiny particles of dirt or dust may get inside the camera body and stick to the image sensor.
If all of your photos contain a blur or dark spot in the same location, there may be dirt on the image sensor.

WARNING! There is a risk of hardware damage. Do not use a dry cloth or commercial cleaning solution to remove dust particles from the surface of the image sensor. Doing so may cause the coating on the image sensor to peel off. Sony does not provide warranty for mishandling of the camera caused by commercial cleaning solutions, cleaning paper, or the like. For cameras with mirrors, be careful not to touch the surface of the mirror. Touching the surface of the mirror may cause malfunction.It is recommended that you do not perform cleaning using any method other than clearing away the dirt with a blower. 

IMPORTANT: For model-specific steps on how to perform the steps below, refer to the operating instructions supplied with the camera.

Follow the steps below to clean the image sensor.

1. If the camera is equipped with an automatic cleaning function, use the automatic cleaning function to remove dirt or dust from the image sensor.
2. If dirt or dust is not removed by automatic cleaning function (on models equipped with the function), clean with a commercially available blower.

NOTE: If cleaning fails to remove the dirt or you do not feel comfortable cleaning the image sensor by yourself, please use a cleaning service.