After opening the image in Photoshop, duplicate the
one and only Background layer. On this new layer, apply a Gaussian
blur filter (Filter | Blur | Gaussian Blur).
For a 8 megapixel photo with a resolution of 3456x2304, somewhere about
25 pixels of blur is ok. Modify the amount of blur according to your
photo's resolution.
Then, reduce the opacity of the new blurred layer to around 20-40%.
The amount is dependent on how much soft focus you want. |