Lub lens yog qhov sib cav tseem ceeb tshaj plaws ntawm lub koob yees duab digital. Yog tsis muaj lub lens zoo, koj cov duab tsis muaj caij nyoog kom ntse thiab ci. Kev txiav txim siab qhov sib txawv ntawm cov lo ntsiab muag yog txhua yam tab sis ua tsis tau tshwj tsis yog tias koj paub cov lus siv los piav qhia lawv.
Lens muaj lub hom phiaj tshwj xeeb, yog li paub tias koj tab tom sim ua dab tsi ua ntej koj mus yuav khoom. Puas yog koj tom qab muaj kev cuam tshuam tshwj xeeb? Puas yog koj tua nyob deb lossis ze heev? Koj cov ntsiab lus yuav yog dab tsi?
Useful Lens Terminology
Kev ua lag luam muaj ntau hom lo ntsiab muag thiab cov ntsiab lus kom phim. Nov yog ob peb nqe lus uas koj pom thaum koj tshawb nrhiav kev yuav khoom.
Zoom
Qee tus kws yees duab xav txog kev zoom raws li qhov loj ntawm daim duab, tso cai rau tus kws yees duab thaij duab ze ze yam tsis tas yuav txav mus ze rau qhov chaw. Txawm li cas los xij, qhov tseeb txhais ntawm kev zoom yog lub peev xwm ntawm lub lens tua ntawm ntau qhov focal ntev. Lub koob yees duab zoom tuaj yeem tua lub kaum sab xis dav, txhaj tshuaj telephoto, lossis ob qho tib si. Tsis yog txhua lub lo ntsiab muag muaj peev xwm zoom.
YOptical Zoom
Optical zoom tuaj yeem hloov qhov ntev ntawm lub lens siv kho vajtse, tsis zoo li digital zoom, uas siv software algorithms. Nws tau suav tias yog "qhov tseeb" zoom: Nws hloov qhov kev nthuav dav hauv cov txheej txheem kev siv tshuab uas tshwm sim ua ntej cov ntaub ntawv mus txog qhov ntsuas pom, siv lub iav kho qhov muag ntawm lub lens.
Nws tsim cov duab zoo dua li qhov zoom digital thiab yog ib qho ntawm cov koob yees duab ruaj khov.
Digital Zoom
Digital zoom siv software hauv lub koob yees duab los hloov lub focal ntev los ntawm kev nthuav cov duab. Vim tias digital zoom cuam tshuam qhov loj ntawm pixels, cov zoom digital tuaj yeem cuam tshuam cov duab sharpness tsis zoo. Thaum muas lub koob yees duab, tsis txhob saib lossis ntawm digital zoom; Feem ntau cov kws yees duab tuaj yeem luam tawm feem ntau ntawm cov zoom digital nrog cov software tom qab tsim khoom. Ua tib zoo saib tus naj npawb optical zoom xwb.
Hloov pauv Lenses
High-end DSLR thiab lub koob yees duab tsis muaj iav tuaj yeem siv cov lo ntsiab muag sib hloov tau los muab cov peev xwm sib txawv. Nrog ntau qhov sib hloov tau DSLR lo ntsiab muag thiab lub koob yees duab tsis muaj iav, cov duab stabilization yog tsim nyob rau hauv, txwv lub koob yees duab co thiab txhim kho cov duab zoo.
Focal Length
Lub focal ntev yog qhov kev ncua deb ntawm qhov nruab nrab ntawm lub lens mus rau qhov focal point (cov duab sensor hauv lub koob yees duab digital). Feem ntau cov koob yees duab digital lo ntsiab muag qhia tus lej no ua ntau yam, xws li 25 hli txog 125 hli. Lub focal length ntsuas ntsuas lub telephoto thiab wide-angle peev xwm ntawm ib lub lens ntau dua qhov kev ntsuas qhov muag pom, uas tsuas yog ib tug lej qhia qhov txawv ntawm qhov dav-angle thiab telephoto ntsuas. Qhov piv txwv 25 mm txog 125 mm yuav muaj 5X optical zoom ntsuas.
Lwm Cov Lus Nug: Pom Koj Cov Ntsiab Lus
Cov ntsiab lus hauv qab no tsis yog nruj me ntsis rau lub koob yees duab lo ntsiab muag, tab sis lawv tseem ceeb kom paub txawm li cas los xij thaum koj mus yuav cov koob yees duab.
NYIAJ LCD
Cov kua siv lead ua kua (LCD) nyob tom qab ntawm lub koob yees duab digital pab koj thav duab, zoo li lub qhov muag pom. Nco ntsoov tias lub LCD tsis tshua muaj 100% ntawm cov duab uas lub koob yees duab yuav tua. Cov kev pab cuam LCD yog qee zaum 95% lossis siab dua, thiab lub koob yees duab specs feem ntau sau cov feem pua ntawm no. Nws feem ntau sib phim qhov pom los ntawm lub lens, tab sis tsis yog raws nraim.
YOptical Viewfinder
Lub qhov muag pom qhov muag muab qhov tsis zoo, tsis yog digital saib ua ntej ntawm daim duab uas tus kws yees duab tab tom yuav tua. Ntawm qhov qis-kawg taw tes-thiab-tua cov koob yees duab, lub qhov muag pom qhov muag tsis khi rau lub lens optics; Hloov chaw, nws feem ntau yog saum lub lens, yog li nws tsis phim cov duab lub lens tua precisely. Nyob rau hauv qhov sib piv, high-end DSLR koob yees duab khi lub qhov muag pom kev rau lub lens optics, muab ib tug zoo meej saib ua ntej ntawm cov duab tom ntej.
Electronic Viewfinder (EVF)
Lub EVF hauv lub koob yees duab digital yog lub LCD me me uas muab sijhawm rau koj los teeb duab. EVF yog ib qho kev sawv cev digital ntawm daim duab. Hais txog kev ua raws li kev pom los ntawm lub lens ntawm daim duab kawg, EVF zoo sib xws rau LCD qhov tseeb.
