产品详细描述：HyperStandardPro-VideoLensYJ20x8.5BIRSYJ20x8.5BKRSCanonisproudtointroducetheYJ20x8.5B,whichhasemergedfromCanon'stopsellingYJ19x9B,alsoknownasthePro-VideoIndustryStandardLens.TheYJ20x8.5BtopsmanyPro-Videostandardlensesbyofferingthewidestfocallength(8.5mm),thehighestzoomratio(20x),andthefastestzoomspeed(1.2secfromwideendtoteleend).Inadditiontoh***ingCanon'sinnovativeInternalFocus(IF)TechnologyandexclusiveShuttleShotFunction,itsnewergonomicallydesigneddriveunitaccountsforitsidealbalanceandcomfort.IFTechnologyPro-VideocamerapeoplecantakeadvantageofCanon'sbreakthroughtechnologythatbroadcastersh***eenjoyedforyears-InternalFocus(IF).InternalFocustechnologywaspioneeredbyCanonandfirstintroducedintotheirBroadcastENGlenses.Ithassincebecometheindustry-standard.InternalFocusisasystemwherethefrontendofthelensremainsstationaryanddoesnotrotate.Onlyinternalelementsmovewhenfocusing.InternalFocusenhancesopticalperformanceandprovidesseveraluserbenefits:-IFimproveschromaticaberrati***,thusincreasingresolution.-IFisnotsensitivetochangeinobjectdistances.-IFdecreasesflarebyuseofsquarefood.-IFenablesahigherlevelofcreativefilterwork.-Evenhe***yopticalaccessoriesattachedattheendoftheLensdoesnotaffectthefocusingoperation.NewErgonomicDriveUnitThenewergonomicallydesignedDriveUnitachievesanidealbalanceandcomfortbyh***ingittilttoanangle.Inaddition,thesizeoftheunithasbeenminimizedtocomfortablyfitinthepalmofthehand.Overall,itimprovesthefeelingofunitybetweentheuserandthelens.ShuttleShotSwitchTheShuttleShotfunctionON/OFFswitchcanalsobeallocatedtoeithertheVTRorRETswitchesbymeansofaDIPswitch.RibbedSurfaceTheribbedsurfaceonthebottomoftheDriveUnitprovidesbetterhandlingcontrol.GripSupportAllowsausertosecurelygriptheDriveUnitwithoutpressingontheVTRorShuttleShotbutt***.LensModelNumberYJ20x8.5BIRSZoomRatio20xBuilt-inExtender2.0xRangeofFocalLength(withExtender)8.5~170mm17~340mmMaximumRelativeAperture(withextender)1:1.8at8.5~113.3mm1:2.7at170mm1:3.6at17~226.7mm(2.0x)1:5.4at340mm(2.0x)Angularfieldofview(withExtender)4:3AspectRatio(8.8x6.6mm)54.7°x42.4°at8.5mm3.0°x2.2°at170mm29.0°x22.0°at17mm(2.0x)1.5°x1.1°at340mm(2.0x)MinimumObjectDistance(M.O.D.)0.9m(10mmwithMacro)ObjectDimensi***atM.O.D.(withExtender)4:3AspectRatio(8.8x6.6mm)85.2x63.9cmat8.5mm4.4x3.3cmat170mm42.6x32.0cmat17.0mm(2.0x)2.2x1.7cmat340mm(2.0x)ze(WxHxL)163.3x103.0x195.4mmApprox.Mass1.39kg(3.06lbs)MacroYesYesLensModelNumberYJ20x8.5BKRSZoomRatio20xBuilt-inExtender-RangeofFocalLength(withExtender)8.5~170mmMaximumRelativeAperture(withextender)1:1.8at8.5~113.3mm1:2.7at170mmAngularfieldofview(withExtender)4:3AspectRatio(8.8x6.6mm)54.7°x42.4°at8.5mm3.0°x2.2°at170mmMinimumObjectDistance(M.O.D.)0.9m(10mmwithMacro)ObjectDimensi***atM.O.D.(withExtender)4:3AspectRatio(8.8x6.6mm)85.2x63.9cmat8.5mm4.4x3.3cmat170mmze(WxHxL)163.3x103x170.4mmApprox.Mass1.17kg(2.58lbs)MacroYesYes)