Originally Posted by rowan

Of course you mean do a search and find the answer, right? That question is asked every second day and the answer rarely changes.

mkx: the dust is on the sensor, which is behind the mirror. You need to go into sensor cleaning mode to flip the mirror up. See your manual for details, it can be a bit fiddly and you need to be gentle. BTW, a blower may not be sufficient to clean it, you may find that it just ends up depositing more dust onto your sensor.