74 http://www.amateurphotographer.co.uk
The lens focused responsively
with no sign of hesitation under
bright sunny conditions Sony A7 III,
Sigma 100-400mm F5-6.3 DG DN OS Contemporary
@ 400mm, 1/2500sec at f/6.3, ISO 1600The lens operates at
a maximum of f/6.3
beyond 235mm Sony A7
III, Sigma 100-400mm F5-6.3 DG
DN OS Contemporary @ 400mm,
1/250sec at f/6.3, ISO 1600
as well as correction for
residual chromatic
aberration. Complementing the
construction are 9 rounded
diaphragm blades, but with a
variable maximum aperture of
f/5-6.3 users will nd themselves
using the lens at its long end to
accentuate shallow depth of eld.
As we’ve seen on other Sigma
DG DN lenses, a stepping motor
is used to drive autofocus and
provide fast, smooth and silent
operation. An autofocus lock
(AFL) button is added to the
barrel to which users can assign
different functions, plus there’s a
focus limit switch that allows
users to control the focus
distance range based on how
close or far they happen to be
working from their subject.
The optical stabilisation (OS)
that’s built into the lens is
effective to four stops on its own.
The great thing about it having OS
built-in is it offers compensation
with older mirrorless models like
the Sony A7 and A7R that don’t
have in-body image stabilisationand unwieldy, but that’s not the
case with this Sigma example.
The E-mount review sample I was
supplied with weighed 1,140g,
which presents a weight saving of
255g over Sony’s FE 100-400mm
f4.5-5.6 OSS G Master.
The t and nish of the lens is
excellent with careful thought to
what materials are used where.
The zoom ring is rubberised and
magnesium alloy is used around
the tripod socket attachment to
ensure this section of the lens is
as strong as it needs to be. To
help keep the weight down some
parts of the barrel are made from
polycarbonate, but these sections
uphold good quality. Carrying my
camera set-up over my shoulder
did highlight zoom creep whilst
walking, however Sigma has
added a zoom lock that can be
engaged at 100mm to prevent
this being a nagging concern. The
spacing and difference in feel
between the zoom ring and focus
ring is such that you can easily
tell the two apart. The former
operates across its range with a
quarter turn and Sigma has
designed the lens hood in such a
way it makes it possible to
operate the zoom by the push/
pull method if you’d prefer. Using(IBIS) as well as those that do.
When it’s paired with cameras
that feature 5-axis image
stabilisation the lens corrects for
pitch and yaw with rotation
around the lens axis and
side-to-side movement being
controlled by the camera. At the
side of the barrel there are two
stabiliser modes with the option
to turn it off when needed. Mode
1 is intended for motionless
subjects, while mode 2 detects
sweeping movements when
panning and switches the IS
correction off in the relevant
direction for sharper results.
The lens has a 67mm lter
thread at the front ready for the
attachment of lters, while
Sigma’s TC-1411 and TC-2011
teleconverters, which are
exclusively designed for L mount,
can be used to extend the focal
length up to 800mm. It has a
robust metal mount and is
compatible with Sigma’s USB
dock (UD-11), but like Sigma’s
teleconverters, this is only
available for the L-mount version.Build quality
Full-frame lenses that cover a
focal length of 100-400mm are
often associated with being heavy