FIGHTING YOUR CORNER
The Canon Magazine 81
EOS S.O.S
riginally introduced
in the 5D Mark II and
50D, peripheral
illumination correction is
now the most common lens
aberration correction,
available across the EOS
range – from the beginner-
friendly 1300D to the
top-end mirrorless EOS R.
This feature is designed to
correct light fall-off, which is
where the corners of an image
can look darker than its centre.
This is something that can
occur even when the lighting is
consistent across the scene,
and is most noticeable when
shorter focal lengths are
combined with large aperture
settings, such as f/1.8 and
f/1.4. With longer focal lengths
the darkening effect can be
quite subtle, to the point that
many people looking at your
picture wouldn’t notice it.
In fact, although evening out
the exposure might give you
technically improved results, it
doesn’t automatically make for
a better picture. Stylistically,
it’s an effect that can suit some
images – portraits can often
benefit from darker edges to
help frame the person and add
interest, for instance. There’s a
reason why popular photo-
editing software includes a
‘vignette’ slider that allows
you to increase the effect.
If you do opt to correct it,
bear in mind that in-camera
correction isn’t as strong as
the correction that can be
applied to Raws in DPP. The
correction effect is also weaker
at higher ISOs, as there’s a risk
of noise appearing at the edges
of the image when darker
areas are brightened up.ens quality can be
measured in a
number of ways,
and the degree to which
distortions are suppressed
is one of them. Wide-angle
lenses suffer to some
degree from what’s known
as barrel distortion – where
the centre of the image
appears to bow outwards,
as if it’s wrapped around a
barrel, hence the name.
It becomes glaringly obvious
when the subject of your photo
includes (what should be)
straight lines, such as
architecture, interiors, or the
horizon in a landscape or
seascape image.
An image taken with a
telephoto lens can exhibit the
opposite effect, with the centre
of the image appearing to be
pinched inwards; this is known
as pincushion distortion. It’s far
less distracting than barrel
distortion, but both can still be
detrimental. Thankfully, both of
these effects can be remedied
by enabling the distortion
correction option.Correcting distortion
involves a certain amount of
pushing and pulling of pixels to
make lines straighter, and this
results in part of the image
being cropped off during the
process. This crop is more
noticeable with wide-angle
shots, as these tend to require
more significant adjustments.
As such, it’s worth leaving a
little room at the edges when
you originally frame your shot.Correction^ off^
Before
After^
Correction^ on^
Dealing with dark corners
Fix distortion in your images
Use peripheral illumination correction to even out brightness across an image
Distortion correction brings back natural shape to wide-angle and telephoto shots
SOFTWARE OPTION
You can also brighten the
corners manually in Digital
Photo Professional, where
a series of sliders gives you
greater control over lens
corrections.O
L
You’ll lose a little around the edges
of the picture with this correction