3 of the really important new features of Vray are covered in this tutorial. All of these really add to Vray's toolset (especially the camera in my opinion). This camera acts just like an actual camera and can therefore create depth of field and motion blur effects by adjusting the aperture and shutter speed. This tutorial shows examples of the basic settings of the camera, but for more understanding of it I would suggest learning about photography. However, these setting examples provide an important resource and good starting point.
For the sun and sky in Vray, this tutorial is a great resource. I have tried these features and achieved some amazing results, so make sure to check it out. The tutorial is HERE.