Adding a Photoshop Lens Blur

This is another one of those “notes to myself” posts – this time about how to add a lens blur to an image (simulating depth of field) in Photoshop CS4. This particular YouTube video did the trick – seems to be the simplest approach to an easy blur.

Here’s my distillation of the process:

1. Open the JPG file.
2. Use CMD-J to duplicate the layer.
3. Switch to Channels and add a mask.
4. Click on both the new Alpha Mask and RGB and then paint the area that you want sharp in the image.
5. Select the RGB channel, pull down Filters-Blur-Lens Blur and adjust the settings as appropriate. Click save.
6. Then go back to the Channels and hold down Cmd while clicking on the Alpha mask – this will re-select the original mask.
7. Pull down Filters-Sharpen-Unsharp Mask and adjust as appropriate. Deselect the selection and you’re ready to save.

Here’s the effect in action.

Before:

After:

Here’s a pretty comprehensive list of additional photography tips from Smashing Magazine.