Canon EOS Rebel T6i EF-S 18-55mm IS STM Lens Kit Instruction Manual - Page 271

f Automatic Sensor Cleaning Whenever you set the power switch to or , the Self Cleaning Sensor Unit operates to automatically shake off the dust on the front of the sensor. Normally, you need not pay attention to this operation. However, you can choose to perform sensor cleaning manually, or disable it. Cleaning the Sensor Now 1 Select [Sensor cleaning].  Under the [53] tab, select [Sensor cleaning], then press . 2 Select [Clean nowf].  Select [Clean nowf], then press .  Select [OK], then press .  The screen will indicate that the sensor is being cleaned. (A small sound may be heard.) Although there will be a shutter sound, no picture is taken.  For best results, perform the sensor cleaning with the camera placed upright and stable on a table or other flat surface.  Even if you repeat the sensor cleaning, the result will not improve much. Immediately after the sensor cleaning is finished, the [Clean nowf] option remains disabled temporarily. Disabling Automatic Sensor Cleaning  In step 2, select [Auto cleaningf] and set it to [Disable].  The sensor cleaning will no longer be executed when you set the power switch to or . 271