Digital Camera - Ken Gilbert

our controlled test environment enables us to benchmark cameras and lenses
under controlled conditions. We
conduct four separate tests for
cameras and three for lenses, all
of which involve shooting a test
chart in a specially configured
room. Full details about the tests
we perform can be found in the
panel on the right of this page.
to minimise the variables
when testing slRs, we use sigma’s
50mm f/1.4 ex dG HsM prime
lens, which is available forevery
camera system.
next, we perform an analysis
of the test images using imatest’s
imatest Master software (www.
imatest.com) and generate a
benchmark figure for each test,
which is then plotted on a graph
against rival products to enable
you to make a direct comparison
scores out of five in one or
more sub-categories and
then applies an overall mark
out of five, enabling youto
tell the wheatfromthe chaff.
Five scores, five meanings:
Forget it
Below average
Good for the money
Very good in all areas
a truly exceptional,
best-in-class product
of which product performs better
under different criteria.
RaW files of all our test results
are available to download from
our website, photoRadar, at
www.photoradar.com/testing.
Benchmarks should not be
seen as a replacement for (or
even a better version of) real
world testing – they won’t tell you
which camera handles best in
the field or is easiest to use, for
example. But they do enable us to
sense-check our real world image
test results and you to make an
accurate comparison of a
product’s capabilities.
no other magazine goes this
far to deliver test results you
can really trust.
awarded to
anyproduct
thatcomes top
in a group test
awarded to any
product that
receives five
stars in a test
awarded to
products that
offerexceptional
value for money
innovative or
breakthrough
products receive
this special award
tHe
appliance
oF science
Digital Camera runs a series of
objective tests under controlled
conditions on both camera
bodies and lenses. we run three
tests in total for lenses and four
tests for cameras. each test
uses imatest’s imatest Master
software to analyse shots of
test cards – here’s how each
test works…
lens tests
distortion
1this test measures the
distortion caused by the lens
and we shoot the simple lined
distortion chart pictured above
and then output an accuracy
percentage in imatest,with 0%
being the most accurate.
cHroMatic aBerration
2this test measures the
appearance of chromatic
aberration and we shoot the
chart pictured. the results
are analysed by imatest and
expressed in pixels, with lower
numbers being better.
sHarpness
3Here we measure sharpness
at different apertures from
the centre to the outer edge.
We shoot the chart pictured and
imatest outputs a figure based
on line width divided by picture
height – high numbers are better.
kitzone
OUR tests explained
camera tests
exposure accuracY
1this measures how accurate
a camera’s exposure system
is and involves shooting the
greyscale step chart pictured.
We focus and spot meter for
grey block M and measure the
deviation from 0 eV in imatest.
dYnaMic ranGe
2this measures the ability of
a camera to capture detail in
the highlights and shadows and
we shoot three images (at -3
f-stops, 0 and +3 f-stops) of the
greyscale step chart pictured.
imatest measures results in eV.
colour accuracY
3this measures colour
reproduction and we shoot
the x-Rite ColorChecker chart
pictured above and output an
accuracy percentage from
imatest, with 100% being the
most accurate result possible.
noise
4this measures colour and
luminance noise and we
shoot the greyscale step chart
pictured, focusing and spot
metering on grey block M. We
then measure the deviation from
0% in imatest.
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