Using the Quick Mask in Photoshop

Sometimes the background is just to much in focus

one way of softening the background is by using the quick mask option.

Click on the quick mask with black on top.  You will be making a mask, so black applies,

and white removes.

So just paint with black at 100%, which paints as red. Paint the parts you DO NOT

want selected.  In this case the family and foreground.

Switch the masking button back to normal and you will have a selection.

Choose Filter>Gaussian Blur, and choose the amount of  focus.   

This is over done to illustrate the effect.

You could also apply a layer mask, and with black on top, run a gradient from bottom to top to

get a varied focus.