Solution
In this camera, whenever you turn the power to on or off, the Self Cleaning Sensor Unit is activated to automatically shake off the dust on the front of the sensor (CMOS).
Normally, you need not pay attention to this operation. However, you can run the sensor cleaning at any time by following the procedures below.
1. Set the power to ⋖ON⋗.
2. Press the ⋖MENU⋗ button to bring up the menu display.
3. Under the [ ] (Set-up 3) tab, select [Sensor cleaning], then press the ⋖ ⋗ button.
4. The screen below will appear. Select [Clean now], then press the ⋖ ⋗ button.
5. Select [OK], then press the ⋖ ⋗ button.
The screen will indicate that the sensor is being cleaned. Although there will be a shutter sound, a picture is not taken.
Caution
If there is dirt or dust that cannot be removed by following the procedure above, please see Manual Sensor Cleaning (EOS 5D Mark III).
Caution
*If the abovementioned items (Digital Photo Professional software/Instruction Manuals) were not included with you camera, please download them from the Canon homepage.