In this video I’m going to show you how to create a blurry background in Photoshop (the shallow depth of field focus). We’re going to apply the blur by using the Lens Blur Filter which allows you to apply the narrow depth of field so that some objects in the image are in focus while others are blurred. Photoshop tips. Nordic360.
To be comfortable shooting manual you will need to know what your necessary adjustments are. Though these settings are all numeric, there isn't some insane math equation that you need to do to find out what to dial