产品详细描述：TheoveralldemandforHDproductioncoupledwiththegrowingdiversityofproductionapplicati***hascalledforanexpansionintherangeofHDlenses.TheHJ21ex7.5Bwasspecificallydevelopedtosupporthigh-endHDproductionwhereminimizationoffocusbreathing(unwantedalterationtoangleofviewthataccompaniesmanipulationofthefocuscontrol),highimagingperformance,extendedfocalrangeandamodestlywideanglec***titutecoreproductionrequirementsfordramaanddocumentaryprogramorigination.Withtheadditionofthenewdigitaldriveunittheshootingversatilityisfurtherenhanced.The7.5mmwideanglesettingandthe21xzoomratioofferaformidableoperationalcombinationforsuchhigh-endproductionwork.(Newdriveisloadedwiththelensthathas‘A’attheendofitsmodelnamesuchas‘IRSEA’,‘IASEA’.)MainFeaturesSpecificallyDesignedforHigh-endHDProductionFocusbreathingandvariati***inpictureperformancewithrefocusingatdifferentobjectdistancesh***ebeentraditionalimagingchallengestohigh-endproductioncallingforhighpicturequality.Byadoptingthenovel3-groupinnerfocussystemandsettingaproperpowerforthefrontlensfixedgroupaswellasthefocusmovinggroup,theHJ21ex7.5Bsucceededinminimizingsuchunwantedphenomenatoanexceedinglylowlevel.Alsothelensisdesignedtomaintainhighopticalperformanceacrosstheentire16:9imageplane,especiallyatthetelephotosideofthefocallength.WithinthestandardBCTVlenslineupsc***istedofWide,StandardandTelephotolenses,theadditionoftheHJ21ex7.5Bestablishesitsownimportantcategorysupportingthespecialimagingrequirementsofthehigh-endHDproductionmarket.HighImagingPerformancewithSpecialOpticalElementsandExclusiveOpticalLayoutWiththegoalofminimizingvariousaberrati***inordertomeettheimagingstanda***ofhigh-endproduction,theHJ21ex7.5Badoptsspecialopticalelementsthatincludetheartificiallyre-crystallized“Fluorite”featuringextraordinarydispersioncharacteristicsandthenewlydevelopedhighindexultralowdispersionglass,“Hi-UD”glass.Theselenselementsarescientificallyexploitedbythedesignofanopticallayoutexclusivetothisparticularlens.Theimagingachievementcanbeseeninitshighopticalspecificati***andextraordinaryperformance.Featuringabroadfocallengthrangeof7.5mmto158mmandamaximumrelativeapertureofF1.9,thelensmaintainsitshighopticalperformancethroughouttheentirezoomrange.NewErgonomicDriveUnitBesidestheexceptionalopticalperformance,anotherremarkablecharacterofthisnewlensisit’snewlydesigneddriveunit.Withthegoalofpursuingeaseofoperation,Canonhasreachedanewdesignbasedonhumanergonomics,refinedbyalongtermresearchandtesting.Ofcourse,alltheadvantagesfromthecurrente-HDxsDigitalDriveUnitsuchas"InformationDisplayforusercustomizesetting","RotaryEncoderforvirtualstudiointegrationandprecisecontrol"and"EnhancedDigitalFuncti***"areinheritedtothenewdriveunit.SeemoreinformationfromourFAQLensHJ21ex7.5BIRSEA/IASEAZoomRatio21xBuilt-inExtender2.0xRangeofFocalLength(withExtender)7.5~158mm15~316mm(2.0x)MaximumRelativeAperture(withextender)1:1.9at7.5~116mm1:2.6at158mm1:3.8at15~232mm1:5.2at316mm(2.0x)AngularFieldofView(withExtender)4:3AspectRatio(8.8x6.6mm)60.8°x47.5°at7.5mm3.2°x2.4°at158mm32.7°x24.8°at15mm1.6°x1.2°at316mm(2.0x)16:9AspectRatio(9.6x5.4mm)65.2°x39.6°at7.5mm3.5°x2.0°at158mm35.5°x20.4°at15mm1.7°x1.0°at316mm(2.0x)MinimumObjectDistance(M.O.D.)0.85m(10mmwithMacro)ObjectDimensi***atM.O.D.(withExtender)4:3AspectRatio(8.8x6.6mm)110.1x82.6cmat7.5mm5.1x3.8cmat158mm55.1x41.3cmat15mm2.6x1.9cmat316mm(2.0x)16:9AspectRatio(9.6x5.4mm)120.4x67.7cmat7.5mm5.6x3.2cmat158mm60.2x33.9cmat15mm2.8x1.6cmat316mm(2.0x)MacroYesSize(WxHxL)175.2x122.5x260.1mmWeight(Approx)IRSEA2.61kg(5.76lbs)IASEA2.69kg(5.94lbs)OperationalAccessoriesFullservo:SS-41-IASD/SS-41-DSemiservo:MS-210D)