What Is a Depth Of Field

1. Small Depth of field is when one part of the image is in focus and the background is not its is blurry 

2.  The diffident is when the small depth field when a part of the image is in focus, A large depth of field is when the image is when the image is in full focus.

3.  My image shows depth of field because some of the image shows focused and some or not in focus .