Digital Photography Hacks [Electronic resources] نسخه متنی

Hack 93 Photograph Zoo Animals Without Bars

With a little photographic wizardry, you can
take pictures of your favorite animals at the zoo and eliminate the
bars that stand between you.

Zoos and animal parks present great
opportunities for wildlife shots that many of us would be unable to
get otherwise. The problem is that we have to contend with those
troublesome bars. Or do we? This hack shows how to set your images
free; you can get great animal shots and eliminate the bars that cage
them.

You can get rid of the bars, or minimize their impact on the photo,
by taking advantage of the same shallow depth of field you use to
blur the background in portrait shots [Hack #27] . However, in this case you
want to blur the foreground. You need to open
the aperture wide to make the depth of field shallow, with only the
subject in focus, not the bars. Figure 8-20 shows
the difference that changing the aperture can make.

Figure 8-20. Same shot at different aperturesf-4.5 and f-36

The easiest way to shoot with the
aperture wide open is to put the camera
in AV (Aperture Value
or, as we refer to it, Aperture
Priority) mode so that you set the aperture while
the camera picks the best shutter speed to obtain a good exposure.
Once you're in AV mode, just set the aperture to as
low a number as possible, such as f-2.8, f-3.5, f-4.5, or f-5.6. If
your camera doesn't have an AV mode, give Portrait
mode a try. This setting usually makes the camera favor a larger
aperture.

The next thing to think about is your position in relation to the
animal and the bars. The ideal situation is for you to be as close as
(safely) possible to the bars while the animal is as far away from
the bars as possible.

You also want to shoot perpendicular to the bars. The greater the
angle you shoot at, the more of an impact the bars will have on the
final photo, because their apparent spacing will become closer. Your
camera's autofocus might not behave well, because it
doesn't know if you want it to focus on the bars or
the distant subject. If this happens, give manual focus a try.

For most photography, I tend to advocate taking the shot a little
wider than you need to and then cropping it later. This allows for
different printing aspect ratios and lets you adjust for crooked
shots. Shooting through an obstruction such as bars at the zoo is an
exception to this rule. You want to zoom in as close as you can; a
focal length of 200mm is better than 100mm. The longer zoom also
helps to blur the bars in the foreground. If you want to see how much
of an impact this makes, take a shot of the entire animal and then
take a shot zoomed in on the animal's face under the
same conditions. You'll see that the bars interfere
much less with the composition when you're zoomed in
tighter on the subject.

One last factor to think about for this type of shot is sunlight on
the bars. Although you can apply this hack under any conditions, the
bars tend to disappear easier when there isn't any
direct sunlight on them. If you are having problems, you might want
to try changing your position and shooting from another angle. If you
can, find a place where a tree is shading a section of the bars. Or,
if you're really patient, wait for a cloud to come
by.

Figure 8-21 summarizes the key factors involved in
hiding bars in your shot. The box on the left shows the ideal
conditions, and the box on the right shows the conditions to avoid.

Figure 8-21. Ideal conditions for eliminating bars

So why does your photo look a little flat? Because
you're not magically making the bars disappear;
you're just blurring them heavily. So, although you
don't see them as bars anymore, they still have an
impact on the photo. The blurring effect casts a gray film over the
image and lowers the contrast of the shot. This effect is more
apparent with thicker, narrowly spaced bars than with wire-thin,
widely spaced bars.

You can compensate for this side effect during
postprocessing in Photoshop. Applying
the Auto Levels command (ImageAuto Levels) should brighten
things right up.

As mentioned earlier, you can use this technique with any camera that
lets you control the aperture, but as a rule of thumb, SLRs (digital
or film) tend to create a narrower depth of field than
point-and-shoot digicams. This narrow depth of field is what
eliminates the bars. So this ability, along with the potential to
choose a lens with wider aperture settings, gives the digital SLR a
bit of an advantage here.

And rememberalthough you can free them from their bars, please
don't feed the animals.

David Goldwasser