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10
Break the rules
Although photographers like to
impose ‘rules’ about aperture, for
example landscapes need to be sharp
and portraits should blur the background,
it’s good to break the rules at times.
Landscapes that use shallow apertures
can look very effective and dreamy, and
an environmental portrait needs to have
both the model and background in focus
to understand the bigger picture about
your sitter. Play around with aperture.14
Sweet spot
Every lens has a sweet spot, which is where the
depth of fi eld is at its crispest and fi nest. To fi nd your
lens’s sweet spot, attach your camera to a tripod and
under a consistent light source frame a sheet of text a
few metres back. Ensure the paper is fl at. Take a picture
at each full aperture setting. Note your aperture system
is split into thirds of stops so for example only shoot at
f/2, f/2.8, f/4, f/5.6, f/8, f/11, f/16, f/22. Settings like
f/3.5 and f/6.3 are thirds of a stop. Review the images
on a computer checking for contrast and sharpness
and decide on your winning sweet-spot setting.13
Pinchofsalt
It’simportanttotakewitha pinchof saltsome
of thecontentyouseein reviewsof fastprimelenses.
Youmightbegettingsharpeningfallofftowards
cornersof theframeat thewideraperturesettingsbut
is thisreallya bigproblemwhentakingwedding
portraits?Andif youareshootingwitha 24mmf/2you
areprobablytryingtoshoota landscape,soit’svery
subjectdependent,andwhatyourcreativeintentis too!12
Chromatic aberration
When you use wider aperture settings,
you run the risk of longitudinal chromatic
aberration. Strong colour fringes appear as an
outline around the edges of objects, and are
especially noticeable in high-contrast situations.
This happens when the lens is unable to focus all
the wavelengths of visible light to the same focal
plane, leaving different colours focused at slightly
different distances. To avoid colour fringing try
stopping your aperture down to a narrower setting.
You can also suppress this colour fringing to a
degree post shoot in image-editing software. The
fl aw is more noticeable with cheaper lenses, so
investing in glass is worthwhile. A different effect
known as lateral chromatic aberration gives colour
fringing towards the corners of the frame. This
can’t be fi xed by stopping down, but is a simple
one-click fi x in raw processing.11
Keep
experimenting
You can have all the scientifi c
knowledge in the world about
aperture (there is a lot), and it still
won’t give you a great image unless
you get shooting. When it comes to
aperture the best way to get to
grips with it is to use it, experiment,
review and keep shooting. Learn
from your mistakes and you’ll
become a far better photographer
and an aperture expert.At wide aperture
settings your image is
more susceptible to
chromatic aberration.
Try closing the aperture
down to remove itYou don’t always need to follow the
rules. Take for example this
landscape that has been shot at f/2.