You can use Levels, Filters, and Layer Blending to give your images a soft focus look. The effect works best on images that have lighter image tones.

I started with a round of capture sharpening. In this case, I used the Highpass Filter Capture Sharpening action in my TLR Sharpening Toolkit. Then I added a Levels adjustment layer to brighten the image.

The next step was to create a new layer by pressing the "Create a new layer" icon at the bottom of the Layers Palette and then merge all of the underlying layers into the new layer by pressing alt-ctrl-shift-e on the PC (option-cmd-shift-e on the Mac). This committed the changes to the image. I renamed the layer to "Merged Layer" to remind myself what I did, if I edit the image at a later date.

You need to duplicate this merged layer. The easiest way is to press Ctrl-J. You want to apply a Gaussian Blur to the layer that is strong enough to make the edges diffuse. I used 25 pixels and named the layer "Gaussian Blur 25 pixel."

The trick to this technique is to use a Lighten blend mode for the Gaussian Blur layer. The pixels in the topmost layer are compared with the underlying layer and only lighter pixels receive the blurred effect. You can adjust the strength of the effect with the Opacity slider. I set it to 35% in this case.

The Lighten blend mode softened the "eye" of this Black-Eyed Susan a bit. A quick Blend If adjustment insured that darker details from the underlying image punched through. The black Blend If slider for "Underlying Layer" was set to 80.

Adjusting the Blend If slider lke this was optional. It is not part of the soft focus effect, per se. But sometimes you may find there are details you want to punch through unaffected by the blur, and using the Blend If sliders is one way of doing it (and a heck of a lot easier in this case than using something like a selection and a layer mask).

Here is the result, with a snazzy gallery frame effect:

Enjoy!