subscribe 0330 333 1113 I http://www.amateurphotographer.co.uk I 8 June 2019 17
9
DoFscaleswork
regardlessof
sensorsize
Thisis a mistakemanyphotographers
willfallintowithouteventhinking.If you
usea lenswithdistanceanddepth-of-
field(DoF)scalesona crop-sensor
camera,it seemsobvioustoemploy
themtosetthefocusdistanceand
aperture.ButDoFscalesarecalculated
forthelens’snativeformat– usually
fullframe– andwithanygivenlens,
yougetshallowerdepthof fieldwith
smallersensors.Thismeansthattoget
therequiredfront-to-backsharpness,
youneedtoclosetheaperturebya
furtherstoponAPS-Cortwostops
onMicroFourThirds.11
Use a tripod at shutter
speeds below 1/15sec
Conventionally this is pretty good advice,
as even with ultra-wide lenses, rotation
around the lens axis and low-frequency,
large-amplitude shake movements can
cause blur when shooting handheld. But
with the latest image-stabilisation (IS)
systems that use 5-axis in-body
stabilisation, the rules have changed,
and you can get sharp results handheld
at really slow shutter speeds –
sometimes longer than 1 second.7
Always use a UV fi lter
There’s a long-running school of
thought that it’s best to use UV fi lters
all the time to protect your lenses. But
with the latest coatings shrugging off
water and grease and being highly
resistant to scratches, lenses are now
more robust than before. I prefer to go
without a protective fi lter unless there’s
a serious risk from water or sand, using
a lens hood to protect against knocks.
10
Turn off IS when
using a tripod
Early lens-based stabilisation
systems didn’t like being used
on tripods; indeed with some
older design IS lenses, you can
actually see the image ‘swim’
across the viewfi nder. So users
were advised to turn IS off to
avoid introducing unwanted
blur. However, newer systems
are much improved and
there’s often no need to
turn them off.6
Focusandrecompose
Backwhenwewereshootingfilm
cameraswithjusta single,centralfocus
area,it wasnaturaltofocusona
subjectthenrecomposetoplaceit
off-centre.It’stemptingtodothesame
now,asit’squickandeasy,butthe
problemis thatit introducesfocus
errorswhenshootingat large
apertures.Nowthatpracticallyall
camerashavemultiplefocuspoints,
makea habitof usingtheoneclosestto
yoursubjecttogetthesharpestresults.
8
In-lensISis
betterthan
in-bodyIS
Withthevarious
cameracompanies
usingeitherin-lens
opticalstabilisation
orin-body
mechanicalsystems,
therehavelongbeen
argumentsabout
whichis better.
Thefactis thatthey
simplyhavedifferent
strengths:opticalIS
is muchmore
effectivewith
telephotolenses,but
in-body systems can
correct for more
forms of shake and
work with lens types
that are diffi cult to
stabilise. With these
advantages being
complementary to
each other, the most
effective systems
now combine both
in-lens and in-body
IS, as we’ve seen
over the past few
years from the likes
of Sony, Panasonic
and Olympus.ThelatestdualISsystems
allowlongshutterspeeds
tobeusedhandheld
Sony Alpha 7 II, 24-70mm f/4,
1sec at f/10, ISO 50A hood will protect your
lens’s front elementDoF scales
assume a
specific
film or
sensor
format