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Technique
Angela Nicholson
Photographer and journalist Angela Nicholson started
reviewing cameras for Amateur Photographer in 2004 and
was our Technical Editor before leaving for new pastures in- Last year she founded SheClicks, a community for
female photographers. squeezymedia.com.
St ron g
and
stable
Who needs tripods when image
stabilisation systems in cameras and
lenses are now so good? Angela
Nicholson explains everything you
need to know to beat the shakes
W
hen image
stabilisation
(IS) first arrived
in photography
in the 1990s it was lens-based
and designed to help us get
better results with telephoto
lenses. It was about avoiding
having to use very fast shutter
speeds in low light. These days
we have lens- and sensor-based
image stabilisation systems,
with some cameras making
use of both, and they’ve
developed to such an extent
that they can even help with
long exposures. But which is
the best system and how do you
get the most from it?
Lens-based stabilisation
Inside a stabilised lens there’s a
gyro that detects the direction,
speed and magnitude of any
accidental movement when the
camera is handheld. This data
is processed and information
about the required
compensation movement is
relayed to a motor that shifts a
floating element (or group of
elements). This compensating
movement is designed to keep
the image that exits the lens on
the same part of the film or
sensor, hence enabling the
image to be made sharp. Of
course this all has to take place
very quickly to be eective.
A key benefit of lens-based
stabilisation is that it’s
specifically designed to suit
that focal length, however, it
means that the lens has to be a
bit bigger, heavier and more
expensive than an unstabilised
lens. It’s especially useful with
long telephoto lenses when the
range of moment required to
compensate for camera shake
can be too large for a sensor-
based system.Sensor-based
stabilisation
Digital photography enables
an alternative form of
stabilisation that takes place
inside the camera. Often
referred to as in-body
image stabilisation (IBIS), this
also uses gyros to detect
accidental camera movement,
but it’s the sensor that ismoved to compensate and
keep the image sharp.
While early IBIS units used
mechanical parts to shift the
sensor, modern ones tend to
use electromagnetic control
which enables faster,
smoother compensation
movements. It also means that
rotational adjustments can be
made as well as up-and-down