Digital Tilt-Shift Photos
Have you ever looked out of an airplane and thought the cars and people
looked like toys? Have you ever wanted to build a scale model of
anything? Me neither. But I have been on hikes and thought the town
below was cute.
The true advantage of an old time view camera was the ability to
correct for parallax by adjusting the relative angles of the lens and
film plane. Buildings could be straightened, fields of flowers more
easily kept in focus through movement of the lens board towards
parallel with the subject. Doing the opposite created a minimized
effect, with low depth of field, much like that experienced in macro
photography. While the digital equivalents of perspective control and
increasing depth of field (ie making things straight and sharp) are
complex, making pictures blurry is a bit easier.
The basic steps are as follows:
- Find a suitable shot. (Anything, even your living room will
work
if the perspective is looking downward and it has some contrast in the
lighting.) - Do some preprocessing to emphasize the possibilities.
(Eliminate
foreground objects, highlight prominent features, increase contrast and
saturation, over-sharpen a little) - Create a narrow band of focus using PhotoShop (or
equivalents) - Create the final crop.
1. Taking the Shot
I decided during a recent hike to take
some shots for a miniature effect. It was a hazy day, but there was
enough contrast. I like street scenes because the cars and buildings
look especially cute. Since I was shooting for an artificial look
anyway, this rather bland shot was fine.
2. Preprocessing in PhotoShop
Using Adobe Raw, I tweaked the color balance, exposure and
saturation.
In this case the tint was lowered (more blue) by 13, the saturation
increased by 13, and the contrast increased by 25. Performing these
steps after blurring may help achieve the best effect, but when
shooting Raw format, it is better to adjust at this stage to get in the
ballpark.
After you open the image in PhotoShop proper, sharpen heavily using an
unsharp mask. (filter>sharpen> unsharp mask.) In this
case, I
used a radius of 5.1 pixels, at 70%. You can see the result in the next
phase – creating a gradient for the blur.
3. Creating the Gradient in an Alpha Channel
Now we need
to create a narrow band of focus to create the shift tilt miniature
effect. In Photoshop, a slick way to accomplish this is by using a
gradient to create a band of decreasing focus. Then the lens blur
filter uses this gradient as a mask.
First the gradient.
1. Set up the new channel.
Open the channels window – under window in the menu bar, if
it’s not visible. Create a new channel. The new channel
(Alpha 1)
should be selected. If not, click on it. Now click the eye to make RGB
visible so your image shows through the channel.
2. Select the gradient tool on the Toolbox
(keyboard shortcut g) (If it
is not visible, right click the Paint Bucket tool and select Gradient
Tool or type SHIFT+g)
3. Select a reflected gradient
4. Set your colors to default (black to
your foreground color, and white to your background color) by clicking
on the tools palette or using the keyboard shortcut (d).
5. Draw the gradient.
It took a couple of tries to get the
gradient I wanted.
Just keep dragging perpendicular to the gradient until you are
satisfied. You want a narrow band of focus that highlights interesting
details in the photo. Once you get the hang of it you can repeat the
steps to generate additional channels, each with a different gradient,
and then use each one for blurring.