For fun I dug an old lens that is seldom used out of the camera bag. I wondered how the old Canon EF 135mm f/2.8 Soft Focus would work on the 70D. It creates an effect you just can't replicate in Photoshop.
The switch rotates lens elements in 135mm f/2.8 Soft focus to add some spherical aberration which kind of gives a glow to things and softens the image while still being in sharp focus. I've tried filters with vaseline smeared, nylon stockings as a diffuser and various blur types with Photoshop. All resulted in a soft image but not in the same way the 135mm Soft focus lens does. It is a great lens for portraits. With just a hint of effect dialed in (you can stop the dial between the numbers and at apertures in the f/5.6 to f/8 range it does wonderful things to smooth skin without going overboard on the glow. Think of those cream smooth 1930 Hollywood starlet portraits.