I purchased a Nikon D5500 from a popular online retailer and it arrived yesterday. I'm still getting used to it. However, I noticed when preforming the built in sensor cleaning operation the camera makes no noise what so ever it is completely silent and there is no vibration. Is this camera defective or is that normal for this model. I can't understand how it works without making some noise or at least feeling a vibration. My Sony A77II makes a buzzing sound and you can feel it shake.