Amateur Photographer (2019-04-13)

LENS TEST Testbench

Resolution

Thelensdeliversa strongsetofMTFresultsfrom

ourImageEngineeringtests.Centresharpness

improvesatallfocallengthsbystoppingthelens

downfromitsmaximumaperturetof/4andf/5.6.

Sharpnessholdsupwellatf/8andf/11,butstarts

todropoffbeyondthispoint.Thesweetspotof

sharpnessis foundaroundf/5.6,withthesolid

anddottedredlinesindicatingcentralandcorner

sharpness is superior at wider focal lengths.

70mmcentre

135mmcentre

200mm centre

70mmcorner

135mmcorner

200mm corner

Sigma70-200mmF2.8

DG OS HSM Sports

Curvilineardistortion

Shading

There’sa dropin illuminationofaround1.4stopsin

thecornerswideopenat200mm,butthisquickly

reducesto0.6stopsbystoppingdowntof/4.Users

willfindthefall-offmoregradualandlessabrupt

at200mm.At70mm,cornersarea stopdarkerthan

the centre at f/2.8, reducing to 0.5 stops at f/4.

70mm f/2.8 200mm f/2.8

70mm 200mm

SMIA TV = -0.7% SMIA TV = 1.5%

We’relookingat a lensthatimprovesonits

predecessorin somekeyareas.Serious

enthusiastsandprofessionalswilllovethe

factit’snowa weather-sealedopticforwhen

outdoorconditionsareagainstthem,and

thethreeAFfunctionbuttonsaroundthe

barrelgiveit anadvantageoverTamron’sSP

70-200mmF/2.8DiVCUSDG2– a lens

thatofferssomebenefits of itsownbeing

some300glighterand£60cheaper.Outof

thetwothough,I mustsaythebuildquality

of thisSigmazoomtrumpsitsTamronrival,

withmoreof a premium,pro-specfeeltoit.

Theeffectiveimagestabilisation,fast

autofocusandexcellentimagequality,not

forgettingitsimpressivesharpnessat wide

aperturesandexcellentcontrol of chromatic

aberrations,allcombine

tomakeit anextremely

appealingfasttele-zoom.

Lighteralternativesare

outthere,butif youcan

putupwithcarryinga bit

moreweightyou’llgeta

trustyperformeroffering

excellent value in return.

Ve r d i c t

Price£1,349

Filterdiameter82mm

Lenselements 24

Groups 22

Aperturef/2.8-f/22

Minimumfocus

distance120cm

Dimensions

94.2x202.9mm

Weight1.8kg

LensmountCanon,

Nikon,Sigma

Included

accessoriesLens

cap,rearcap,lens

hood, lens case

Data file

GOLD

restcomfortablyin thepalmof yourhand
duringlongspellsof handheld shooting.

Imagequality
Inspectingreal-worldimagesconfirmedwhat
I wasseeingonthebackof thecamera.It’s
a lensthatproducesimpressivelysharpand
attractiveresults.Oneof itskeystrengthsis
thewayit controlschromaticaberrations.
Colourfringingis verywellhandledalong
high-contrastedges,andat thecornersyou
won’tfindyourselfrushingtoplacea tickin the
‘Removechromaticaberration’boxoradjust
thedefringeslidersduringrawprocessing.The
fairlyfastfall-offin focuswhenshootingat the
lens’smaximumapertureat itsmaximumfocal
lengthalsorequiresyoutobewatchfulof your
focuspointpositioning.Nailit andyou’llbe
rewardedwitha wonderfuldepthtoimages.
StudyingourImageEngineeringresultstells
usthatthelensresolvesitssharpestresultsat
thewidestendof itsfocalrange.Stoppingthe
aperturedowntof/4andf/5.6seescentre
sharpnessimproveat allfocallengths.Edge
sharpnessnevermatchesthatwhichis
resolvedin thecentre,andthedottedlines
onourMTFgraphrevealsthatcorner
sharpness,likecentresharpness,is best
at thewiderendof thezoomrange.
Vignettingis evidentwhenthelensis usedat
itsmaximumaperture,bothat thelongand
shortendsof thezoom.It’smoregradualat
200mmthanit is at 70mmanduserswillfind
thatthecornershadingcanbealleviatedfairly
quicklybyclosingtheaperturebya couple
of stops.Thelensdisplaysmildbarreldistortion
at thewideend,whichturnstopincushion
distortionat telephotolengths,butthisisn’ta
majorconcernandcanbeeasilyfixedasand
whenlensprofilesstarttobecomeavailable.
Thelenswastestedovera three-week
periodwithmultipleCanonfull-frameDSLRs,
butit’simportantto notethatit canalsobe
usedwithcrop-sensor(APS-C/DX)modelsand
is equivalentto a 105-300mmtelephoto
zoom on a camera with a 1.5x crop factor.

Asis typicaloftelephotozooms,thelensexhibits

barreldistortionat70mm,turningtopincushion

distortionaround100mm.Thelevelofdistortion

isn’ta majorconcernandis unlikelytobeanissue

forthemajorityofsubjectsit’llbeusedfor.If you’d

liketoproducedistortion-freeimages,shootin raw

and take advantage of lens profile corrections.

Animagecapturedatthe

sweetspotofsharpness

CanonEOS5DSR,70mm,

1/1250sec at f/4, ISO 400

subscribe 0330 333 1113I http://www.amateurphotographer.co.ukI 13 April 2019 49