Tilt-shift photography seems to be getting a little more attention lately, thanks to digg. And so have the corresponding Photoshop tutorials on how to fake this effect in Photoshop. Keith Loutit also created a wonderful video version of a miniaturized monster truck rally sped up just the way Homer Simpson would like it! But creating a true tilt-shift setup can be expensive. Besides, do you really gonna void the warranty on that new digital SLR to build a real tilt-shift setup anyway?
While some pieces really pull it off well, others seem to fall short in one way or another. The prime reason for this failure is when items fall out of the focal range they should remain in. The extremely shortened depth of field makes can make scenes with high vantage points appear like toy miniatures. However, when you come closer to the horizon, elements that stand above that plane are irregularly blurred using the faux digital technique. The example below shows the untouched photo, a version created Robert Palmer (and who knows... maybe it's that Robert Palmer!)
The next example shows the tilt-shift effect applied.
The spherical structure clearly started in the main focal area, yet the top of the sphere is blurred enough that it loses realism. To be fair, Robert does acknowledge this and tries to sharpen the top of the sphere, but the effect isn't the same in the end.
Decidedly so, in the pursuit of realism, the original photo's alpha was adjusted to make sure the sphere stayed in focus. The next couple examples show the maximum limits of 'perfect focus' or 100% white. DOF begins to falloff as the gradient turns to black. Assuming the concrete ring at the base of the partially-sunken sphere goes all the way around in a circle, then the sphere itself is fully within the perfect focal range. In Photoshop, make a rough approximation of the sphere with the Circular Marque and fill with white directly in the Alpha channel - You can do this in a separate layer and paste it into a channel before applying the Lens Blur... There's many ways to skin the same cat in Photoshop all yielding the same results.
The modified alpha channel clearly shows the sphere is now in the same focal range from top to bottom.
Photoshop guides overlaying for comparison after Lens Blur was applied.
Of course, from what I could see, the end result was much more convincing. What do you think? A slight bump in contrast and some spot sharpening with a soft brush in certain spots and this scene begs for a toy train track to be built nearby.
"You don't stop playing because you get old... you get old because you stop playing" -Unknown