When an image has out-of-focus, detail-less areas, there’s really no need to apply universal sharpening to these areas: all we end up doing is amplifying the image noise. As such, it ’s often better to apply selective sharpening to different areas. There are several ways to do this. You could use layers, selections and masks in Photoshop to zero in on different areas (we’ll explore a few techniques for this later on).
When an image has a shallow depth of field and blurred background like this, there’s no point sharpening the blurred areas, as it will only increase image noise.