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As a photojournalist, I've always been partial
to my "normal" lens: the wide angle. Now, as a digital
photojournalist, my wide angle attachment stays on my camera
about 80 percent of the time, effectively cutting my zoom range
to 24-85mm (approximately 35mm equivalent).
With the Macro mode turned on permanently, I
find this is a setup that is ready for virtually any subject,
except wildlife.
But wide angles do present some problems with
image distortion. Point a wide angle up at a tall building and
the building will seem to fall away in altered perspective.
Here's a simple fix in Photoshop for that problem (it also works
for distorted perspective when the lens is pointed down).
Here's a shot of Singapore's skyline from Boat
Quay. Even from a distance, the downtown buildings were so tall
that I had to tilt the lens up to get them all in the image.
Note that they tend to be leaning in as if Singapore isn't built
on a firm foundation (which it isn't).
For purposes of the tutorial, I've sent the
image to its own new layer (Command/PC: Control-J) and unlocked
it. With the Move tool selected, I choose Free Transform
(Command/PC: Control-T).
Next, select the upper right corner handle and
click and hold down, then hold down Command-Option-Shift
(Control-Alt-Shift) and drag the handle to the right. As I do
so, the left corner moves out as well, correcting the tilting
perspective.
While this technique brings the perspective to a
normal view, it also has the effect of shortening the buildings.
To correct this, grab the center bottom handle and drag it down
until the buildings look their correct height.
When you click the Return key, the image will be
corrected and some portions of the image will be automatically
cropped.
Now, on to a second kind of distortion. My Nikon
WC-E24 lens (the older, smaller in diameter version) is
notorious for Barrel Distortion (perpendicular images bowing out
at the edges like the sides of a barrel).
For most images, I live with the effect. Also, I
can use Andromeda's Lens Doc plug-in for precise correction. But
here's a simple correction technique in Photoshop.
Note that the pillars on each edge of this
picture have a graceful bow to the outside. I've sent the image
to its own layer (Command/PC: Control-J) and erased the
background image to white, and finally increased the canvas size
to create a white border for this tutorial.
The image of Man Mo Temple in Hong Kong doesn't
have any vertical lines in its center and the distortion of the
rafters isn't as noticeable as the vertical pillars. This is an
ideal image for the Pinch filter.
Choose Filter>Distort>Pinch. For my 24mm lens,
I've found a factor of 9 pixels perfect. You may wish to
experiment with a lower number for your particular image but if
you go over 10, perhaps it's time to shop for a new lens.
Now you can see the effect of the Pinch filter
against the white background. Unless you like wavy edges, use
the Crop tool (C) and trim the image down to square edges.
Next week, we'll tackle a slightly more complex
variation of wide angle distortion. |