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About Joe...
Joe Farace is a Colorado based writer and photographer who photographs a wide
variety of subjects.
Dear Diary: The first thing your eyes see when looking at
an image is sharpness, then brightness, and finally warmth, but there are varying
degrees of sharpness. Some photographs are what might be called “acceptably”
sharp, while others might be termed “critically” sharp. It’s
been my experience that, depending upon how they are captured, some images are
sharper than others.
Unsharp Masking
One of the biggest advantages digital imaging has over traditional techniques
is the ability to sharpen images. Many image-editing programs include a Sharpen
command that works by raising the contrast of adjacent pixels; sometimes this
increases apparent sharpness at the expense of overall contrast. Some photographs
can handle additional contrast before losing highlight detail, while others
can’t. A better solution is to use the unlikely named and wonderfully
practical Unsharp Mask (Filter>Sharpen>Unsharp Mask) command that’s
found in Photoshop and other enhancement software.
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Unsharp Mask’s preview window allows you to see the sharpness
of the finished image before it’s sharpened. The dialog
box movable “hand” you can use to choose a particular
portion of an image to see the effect of your sharpening efforts.
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Unsharp Mask’s dialog box provides three sliders for controlling sharpness.
The Amount slider displays the percentage of sharpening that will be applied.
The Radius slider determines the number of pixels surrounding the edge pixels
for sharpening. Lower values sharpen the edge pixels, while higher values sharpen
a wider range. The Threshold slider determines how different sharpened pixels
must be from the surrounding area in order to be considered edge pixels.
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Smart Sharpen’s Fade Amount softens the amount of sharpening
applied in the first tab but only for shadow or highlight areas.
There’s also a Radius command and a Tonal Width slider that
determines the amount of shadow or highlight area that will be
modified.
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Photoshop CS2 adds a new Smart Sharpen command (Filter>Sharpen>Smart
Sharpen) to the Sharpen menu. Similar to Unsharp Mask, it includes an Advanced
mode with three tabs, including Shadow and Highlight. The first two sliders
under the Sharpen tab are Amount and Radius as in Unsharp Mask, but in place
of Threshold there’s a menu that lets you control sharpness for a specific
problem, including Gaussian, Motion, and Lens Blur.
INTENTIONAL Blur
One of the best ways to capture soft, blurry images with style is with a Lensbaby
(www.lensbabies.com).
This flexible camera lens creates an image with an area of sharp focus surrounded
by a graduated blur. When using a Lensbaby, you shift the in-focus area by bending
the flexible lens tube. As you move the lens up, down, left or right, the area
of sharpness shifts, producing blurring and prismatic color distortions in the
rest of the image. You can control the size of the sharpest area and the overall
level of blur by using one of four apertures.
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This photograph was made with a Canon EOS-20D and an EF 28-105mm
zoom lens that was set at about 100mm (approximately the focal
length of a Lensbaby).
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Replacing the Canon zoom with a Lensbaby 2.0 and using its flexible
design to find an area of sharp focus near the center while allowing
the rest of the image to go soft focus is one of the joys of using
this flexible lens.
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