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http://www.magazinesdirect.com.Tech TalkofessorNewmanon...BobNewmanis currentlyProfessorof ComputerScienceat theUniversityof Wolverhampton.Hehasbeenworkingwiththedesignanddevelopmentof
high-technology equipment for 35 years and two of his products have won innovation awards. Bob is also a camera nut and a keen amateur photographer
terchangeableamera lensesI
t’saninterestingfactthata
modernmirrorlessdigital
camerais cheaperto
manufacturethana lens.A
cameracomprisesassemblyitems
thataremassproducedusing
lithography(printing)processes.
Comparedwitha filmcamera,the
mechanicalfilmmovementhas
beenreplacedbya semiconductor
sensor,theopto-mechanical
viewfinderassemblyis replacedby
anLCDorOLEDdisplay,produced
usingessentiallythesame
processesassemiconductors.Only
themechanicalshutterremainsas
a componentrequiringprecision
assemblyfromvariousmechanical
parts– andthere’sa slowtransition
frommechanicalto electronic
occurringwithrespectto shutters.
Bycontrast,lensesstillconsistof
numerousopticalandmechanical
parts,requiringprecisionhand
assembly.Asa result,thecost
equationbetweencamerasand
lenseshassteadilychanged,with
lensesbecomingrelativelymore
expensivethancameras.It might
beexpectedthatthiswouldcause
a progressivereconfigurationof
camerasystems,andin a sense
thishashappened.Threeof the
majorcameramakershave
compatiblecamera
systemswith
differentsensor
sizesavailable.
Thisallowsa
photographer
tochangethe
functionof the
lensbyswapping
thecamerabody
attachedtoit.
Butthisapproach
onlygoessofar.A
lensis notonly,orevenprimarily,
definedbyitsfocallength.Lenses
aredesignedforanangleof view,
rather than a focal length. Thus, a
35mmlensis likelytobequite
differentif designedforanAPS-C
camera,forwhichit wouldbea
‘standard’lens,anda full-frame
camera,whereit wouldprovidea
moderatewideanglecapability.TheGXRconcept
Fromthis,a morethoroughgoing
approachtoredesigninga camera
systemaroundtoday’scamera/
sensoreconomicswouldbeto
providea systembasedonsensor/
lenspairs:a lensdesignand
sensorwouldbepairedtogive
anoptimumsolutionforeach
photographicsituation.Thistype
of systemwasproduced,justonce,
in 2009in theshapeof Ricoh’s
GXR.The‘camera’wasessentially
a bracketwitha batteryholder
anduserinterface(includingrear
screenandprovisionfora plug-in
electronicviewfinder).Intothis
couldbeslottedlens/sensorunits.
Whileinnovative,theGXRwasn’t
a rip-roaringsuccess.Thereare
severalcontributoryfactorstothis.
Firstly,it wassomewhatahead
of itstime,in termsof whatthe
marketwasreadyfor.Atthetime,
therewasanobsessionwith
sensorsize(toanextent,therestill
is) without recognition that it is thecombinationof lensandsensor
asanintegratedsystemthatis
important.Secondly,thechoiceof
lens/sensorunitsdidn’t,in myview,
showmuchclarityof thinking.For
example,thereweretwo‘standard
zooms’,oneusinganAPS-C
sensorandtheothera 1/1.7”
sensor.Thecropfactorbetween
thesetwosensorsis 3.Thelarger
sensorlenshadanf-number
rangeof 3.5-5.6,whilethe
smallerranfrom2.5-4.4,
equivalentto7.5-13onthelarger
sensor.Bythestandardsof 1/1.7”
sensorsthiswasa veryslowlens,
lenseswithf/1.8at theshortend
beingquitecommon.Sucha lens
wouldhaveprovidedmuchthe
sameperformanceastheAPS-C
lens/sensor;thereforethe
complexityandexpenseandsize
of theGXRbroughtnoadvantages
overa compactcamera.
However,thesameideahas
beenresurrectedin anotherform.
Severalnewphonesincludingfor
instancetheiPhone11,sportan
arrayof camerasthatoffer
differentanglesof view.Theseare
designedasoptimisedlens/sensor
systemsandcombinetogetherto
givethephoneitselfanextended
photographic capability.TheRicohGXRwasinnovativeyetnotasuccess– has
the time now come to re-evaluate the idea behind it?Inonesensethe
oddballGXRwas
theforebearofthe
modernmulti-
camera phone