Amateur Photographer - UK (2019-08-23)

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LENS TEST Testbench

Resolution

OurImageEngineeringMTFtestswerecarriedout

withthelenscoupledtoCanon’s50-million-pixel

DSLR,theEOS5DSR.Thesolidredlineshowsthat

there’sanimprovementwhenyoustopdownfrom

f/1.4,withcentresharpnesspeakingaroundf/4.

Cornersharpnesspeakslaterin theaperturerange,

withthesweetspotbeingfoundaroundf/5.6.Push

beyondf/8tof/11andf/16andyou’ll start to notice

softening from diffraction.

28mm centre 28mm corner

Sigma 28mm

F1.4 DG HSM Art

Curvilineardistortion

Theresultsfromourdistortiontestsrevealthatthe

lensexhibitsminorbarreldistortion;howeverit’s

wellcontrolledandcruciallydoesn’tdropbelow

-1.0%TVSMIA.Therecordedfigure(-0.9%TVSMIA)

isn’tquiteasimpressiveaswhatwerecorded for the

24mm F1.4 DG HSM Art (-0.7% TV SMIA).

Shading

Shootwideopenatf/1.4andyou’llbeabletomake

outgradualvignettingattheedge,whichmeasures

approximately1.7EVdarkerthanthecentre.Stop

downtof/2andyou’llfindit reducesconsiderably,

andbyf/2.8it’sbarelyvisible.If thevignetting

disturbsyouorif youplantoshootregularlyat

f/1.4, it’s easy to remove during post processing.

28mm f/1.4 28mm f/2.8

28mm

SMIA TV = -0.9%

Ifyou’reaftera fast28mmprimelens,the

numberof optionsavailablearequitelimited.

CanonoffersthesmallandlightweightEF

28mmf/1.8USMandEF28mmf/2.8IS

USM,butlacksa 28mmf/1.4in itsL series.

NikonhastheNikkorAF-S28mmf/1.4E

ED,butit’sverycostly(£1,749).There’sthe

sensationallysharpZeissOtus1.4/28and

compactSummilux-M28mmf/1,4ASPH

fromLeica,butagainyouneeddeep

pocketsandbothof thesearemanualfocus

only.Basedonthisselectionyoucansee

whySigmawaskeentomakeitsownlens

andofferit in allthemajorlensmounts.

Optically,thelensis verygood. I expected

it tobea touchsharper

at f/1.4,butit is quickto

sharpenupwhenyou

stopdown.I can’tsee

it beingin demandas

muchasSigma’s24mm

f/1.4and35mmf/1.4

primes,whicharelighter

and£470and£450

cheaper,respectively,

butit fulfils a gapin the

rangeandis yetanother

superb Sigma release.

Verdict

Anexampleofthebokehyoucanachievewideopen at f/1.4.Canon EOS 5D Mark III, 1/1600sec at f/1.4, ISO 400

Price£1,099

Filterdiameter77mm

Lenselements 17

Groups 12

Apertureblades 9

Aperturef/1.4-f/16

Minimumfocus

distance28cm

Dimensions

8 2. 8 x 10 7. 7m m

Weight865g

LensmountCanon,

Nikon,Sigma,Sony

E mount,Panasonic/

LeicaL mount

AccessoriesLens

cap, lens pouch

Data file

versionofthelensonthePanasonicLumix
S1R,butwe’retoldthisisn’tduetoarriveuntil
December.InsteadI testedit withthe50MP
CanonEOS5DSR.
A wideanglelensmightnotbethefirston
yourradarforshallowdepth-of-fieldwork,
butshootclosetosubjectswideopenatf/1.4
andit cancreatea pleasingseparationwith
lovelyblurredbackgrounds.Youdon’tneedto
shootquiteascloseasyoudowitha 24mm
f/1.4primeforbackgroundblurtobeobvious,
butyoudoneedtobewatchfulofyour
focusingtechniquewhenshootingwideopen.
It’snobadthingtofireoffa fewframesto
ensureyoubagonethat’spin-sharp,asany
smallshiftin movementis enoughtothrow
thefocusoff.
Nailthefocusat f/1.4andyou’llgetsatisfying
resultsthatstandapartfromwideangleshots
takenat thesamefocallengthona standard
f/4zoomlens.I wouldn’tgoasfarassaying
thatit’smesmerisinglysharpin thecentreat
f/1.4,andit is perceptiblysofterin thecorners
thanthecentre,butstopdownandyouwill
starttonoticeit sharpeningup.Whilethe
centreof theframeis sharpestat f/4,users
willwanttouseanapertureof f/5.6tolocate
thesweetspotfromedgetoedge.Stopdown
tof/11andf/16andtheimagestartstosoften
becauseof diffraction.It makessensethatf/16
is limitedastheminimumaperture.
I noticeda hintof greenandpurplefringing
alonghigh-contrastedgesat wideapertures
wheninspectingimagesat closemagnification,
butthiswasquicklyresolvedbyincreasingthe
purpleandgreenamountDefringeslidersto
a valueof +5in AdobeCameraRaw.
Barreldistortionis lowwitha slightbendof
straightlinestowardstheedgesof theframe,
butagainit’snotimmediatelyobviousin
real-worldimages.Asforvignetting,there’san
obviousfall-offin brightnesstowardstheedge
at f/1.4.Stoppingdowntof/2seesa big
improvementandbyf/2.8corner
shading is virtually eliminated.

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