Depth-of-Field and Blurring
Depth-of-field, in traditional photography terms, is the range of the focus on a lens. And, technically, in every photo it's always physically there, but could either be a narrow or a wide depth-of-field. A close-up of a flower usually has a narrow depth-of-field. A huge landscape shot from far away usually has a wide depth-of-field.
In the 3d world, the term is used to really only to describe the close-up effect. While you should always make some effort to blur out less-important parts a little, using depth-of-field effects can really make your main focus obvious.
Nowadays most 3d Packages come equipped with a depth-of-field filter or effect already, but here's one easy way to fake it.
Here's where we left off:
When thinking about depth-of-field you need to think about focus, this is the target area that I want to remain focused, everything in red needs to be blurred at least a little, if not drastically.
To start off the blurring we need to duplicate our work copy layer (name the duplicate "blur copy") and then turn off every other layer except the "blur copy" layer and the "work copy" layers.
Select the "blur copy" layer and use Filter>Gaussian Blur on it. I used a radius of about 6.7.Yes, this Gaussian Blur does blur everything. But we're going to use masks to minimize the effect in our focus areas.
After clicking OK then apply a mask to the "blur copy" layer.
By painting black on the mask, we can hide the effects of the blur and allow the crisp "work copy" layer to show through. This really is a matter of preference but its important to keep in mind the distance areas are from your focal point. I started by using the airbrush at 40% to reveal my focus area.
At this point you need to visualize your 3d scene.Things that are either really in front or really behind the focal point will become blurred out, here's how I visualized the image.
After I finished painting the mask, here's how it looked, it's OK if yours doesn't look exactly the same, just remember, when working on the mask in this case, what is white will be completely focused (from the layer underneath) and what's black will be completely blurred. Anything grayish will be a mix somewhere in-between.
Use the bracket keys "[" and "]" to change brush sizes. Use Shift+brackets to change between harder and softer brushes. Use the numpad (0-9) to change the brush opacity.
You can see that I didn't follow my "visualization" exactly, but it's pretty close. I focused or blurred additionally for design purposes too.
Here's what the mask would look like in the actual image. There are plenty of other ways to blur parts of your image, but this way maintains a focused version underneath it all too.
After unhiding all the other layers, we can see our picture is starting to get that "Photoshop't to death" feel. That's OK, this is the "Dante's Peak" of examples: something we're using to shove as many different possibilities as we can imagine into it at once. We're now ready to move on to the next step, Noise!