The Iris Blur tool in Photoshop provides a number of options for selectively manipulating the focus within your images. While it can’t increase the focus on objects from poorly shot images, it can emphasize key areas of a photograph by blurring less important objects into the background to create a vignette effect.
This tutorial is adapted from our new 9-hour Photoshop CC For Photographers training course by Andy Anderson. You can order it as a DVD or download, or get it streaming online through our unlimited Learning Library.
Accessing the Tool
You can activate the Iris Blur tool once your image is open by going up to the Filter menu, going down to Blur and choosing Iris Blur.
This immediately brings up a crosshair interface with multiple points for configuration we’ll look at below.
Moving and Adjusting your Blur Strength
The flexibility of the Iris blur tool becomes apparent once you understand the adjustment and configuration options available. The first thing you should know is how to move your focus area. Simply click and hold your mouse over the smallest circle in the center of the crosshairs, and you can drag the focus area anywhere over your image. You can also click on any other part of your image to create new crosshairs, though with this effect, multiple vignettes are usually not desirable.
Once you’ve chosen the area you’d like to emphasize, you’ll want to increase or decrease the strength of the blur just outside of the focus area. Click and hold down your mouse over the ring around your center circle and drag clockwise or counterclockwise to adjust accordingly.
You can also use the Blur setting within the Blur Tools box on the right hand of your screen.
Setting Your Points
You can also adjust the level of blur at the edges of your focus area by clicking and dragging the four internal points available. These set the level of blur between the interior area of your selection and the outer edges, essentially the transition area of your vignette.
To move a single point independently, hold down the Alt key to click and drag a point.
The four smaller, outside points at the edges of your selection circle can be used to resize and rotate your selection area. Hold Shift to resize without rotation, and use the diamond icon if you’d like to adjust the overall shape of your focus area to make it more or less circular, as shown below.
Adjusting Focus within Your Selection area
Finally, if you’d like to add a degree of blur to the center of your focus selection, you can use the Focus setting in the toolbar above your image. By default, the Focus is set to 100 percent.
To see Andy demonstrate these features in realtime, here is a quick video from Chapter 11 of the Photoshop for Photographers tutorial series.