Ib qho teeb meem tsis meej pem thaum kho dua tshiab rau DSLR yog nkag siab qhov sib txawv ntawm tag nrho cov ncej thiab cov koob yees duab cropped. Qhov no tsis yog ib yam uas koj xav tau tiag tiag thaum siv lub koob yees duab compact, vim tias cov lo ntsiab muag built-in tau tsim los ua kom qhov sib txawv tsis pom. Tab sis, thaum koj pib saib mus rau hauv kev yuav lub DSLR, kev nkag siab tag nrho cov ncej piv nrog cov qoob loo sensor sib piv tuaj yeem pab koj zoo heev.
Lub Koob Yees Duab Tag Nrho yog dab tsi?
Rov qab rau hnub ntawm kev yees duab yees duab, tsuas muaj ib lub sensor loj hauv 35mm kev yees duab: 24mm x 36mm. Yog li, thaum tib neeg xa mus rau "tag nrho cov duab" lub koob yees duab hauv digital photography, lawv tab tom tham txog 24x36 sensor loj.
Hmoov tsis zoo, cov koob yees duab puv puv kuj zoo li tuaj nrog tus nqi siab heev. Qhov pheej yig tshaj tag nrho lub koob yees duab Canon, piv txwv li, yog ob peb txhiab daus las. Cov kws yees duab tshaj lij siv lub koob yees duab puv puv, vim tias lawv xav tau cov yam ntxwv ntxiv. Cov kev xaiv yog "cropped thav duab" koob yees duab, los yog "crop sensor" koob yees duab. Cov no muaj tus nqi pheej yig dua, uas ua rau lawv nyiam ntau dua rau cov uas pib nrog DSLRs.
Lub koob yees duab Cropped yog dab tsi?
Ib kab lus hlais lossis sensor zoo ib yam li kev noj nruab nrab ntawm daim duab thiab muab cov npoo sab nraud pov tseg. Koj nyob nraum tseem tshuav nrog cov duab me ntsis thinner dua li qub-zoo ib yam li cov qauv APS zaj duab xis luv luv. Qhov tseeb, Canon, Pentax, thiab Sony feem ntau xa mus rau lawv cov qoob loo sensors li "APS-C" koob yees duab. Tsuas yog kom tsis meej pem qhov teeb meem, txawm li cas los xij, Nikon ua tej yam txawv. Nws cov koob yees duab tag nrho mus nyob rau hauv lub moniker ntawm "FX," thaum nws cov koob yees duab cropped yog hu ua "DX." Thaum kawg, Olympus thiab Panasonic / Leica siv cov hom qoob loo sib txawv me ntsis hu ua Four Thirds system.
Cov qoob loo ntawm lub sensor sib txawv me ntsis ntawm cov tuam ntxhab thiab. Feem ntau cov neeg tsim khoom cog qoob loo me dua qhov ntsuas tag nrho los ntawm 1.6 piv. Tab sis, Nikon tus piv yog 1.5 thiab Olympus tus piv yog 2.
Yuav ua li cas Cropping cuam tshuam Lenses
Ntawm no yog qhov sib txawv ntawm daim duab puv thiab cov kab lus txiav tawm tiag tiag los ua si. Nrog rau kev yuav lub koob yees duab DSLR tuaj txog lub sijhawm los yuav tag nrho cov lo ntsiab muag (muab koj cov peev nyiaj). Yog tias koj tuaj ntawm lub koob yees duab yees duab keeb kwm yav dhau, koj yuav twb muaj ib lub tswv yim ntawm cov lo ntsiab muag sib hloov tau tso. Tab sis, thaum siv lub koob yees duab cropped sensor, koj yuav tsum nco ntsoov lub focal ntev ntawm cov lo ntsiab muag txawv. Piv txwv li, nrog Canon koob yees duab koj yuav tsum tau muab qhov ntev focal ntev los ntawm 1.6, raws li tau hais los saum no. Yog li, 50mm tus qauv lens dhau los ua 80mm. Qhov no yog ib qho txiaj ntsig zoo rau teleptons, raws li koj tau txais sab dawb millimeters, tab sis sab flip yog qhov lens-lub lenses ua qauv.
Cov neeg tsim khoom tau los daws cov teeb meem no. Rau Canon thiab Nikon, uas ob leeg tsim cov koob yees duab tag nrho, cov lus teb yog los tsim ntau hom lo ntsiab muag tshwj xeeb tsim los rau cov koob yees duab digital-qhov EF-S ntau yam rau Canon thiab DX ntau rau Nikon. Cov lo ntsiab muag no suav nrog ntau lub kaum sab xis dav uas, thaum nthuav dav, tseem tso cai rau qhov dav ntawm qhov pom. Ob lub tuam txhab tsim lub lens zoom uas pib ntawm 10mm, yog li muab qhov tseeb focal ntev ntawm 16mm, piv txwv li, uas tseem yog lub lens wide-angle. Thiab cov lo ntsiab muag no kuj tau tsim los txo qis distortion thiab vignetting ntawm cov npoo ntawm daim duab. Nws yog tib zaj dab neeg nrog cov neeg tsim khoom tsim tshwj xeeb cov koob yees duab cropped sensor, vim tias lawv cov lo ntsiab muag tau tsim los ua haujlwm nrog cov koob yees duab no.
Puas Muaj Qhov Sib Txawv Ntawm Hom Lens?
Muaj qhov sib txawv ntawm lo ntsiab muag, tshwj xeeb yog tias koj yuav mus rau hauv Canon lossis Nikon systems. Thiab ob lub tuam txhab tsim khoom no muaj ntau yam ntawm cov koob yees duab thiab lo ntsiab muag, yog li nws muaj peev xwm koj yuav nqis peev rau ib qho ntawm lawv. Thaum cov lo ntsiab muag digital yog tus nqi sib tw heev, qhov zoo ntawm optics tsuas yog tsis zoo ib yam li thawj zaj duab xis lo ntsiab muag. Yog tias koj tab tom nrhiav siv koj lub koob yees duab rau kev yees duab yooj yim, ces tej zaum koj yuav tsis pom qhov txawv. Tab sis, yog tias koj tab tom nrhiav kom mob siab rau koj qhov kev yees duab, ces nws tsim nyog nqis peev rau qhov qub ntawm lo ntsiab muag.
Canon's EF-S lo ntsiab muag yuav tsis ua haujlwm ntawm lub tuam txhab lub koob yees duab puv npo. Nikon DX lo ntsiab muag ua haujlwm ntawm nws lub koob yees duab tag nrho, tab sis ua li ntawd ua rau poob hauv kev daws teeb meem.
Hom ntawv twg tsim nyog rau koj?
Cov koob yees duab puv puv pom tseeb muab rau koj siv cov lo ntsiab muag ntawm lawv qhov ntev focal ntev, thiab lawv tshwj xeeb ci hauv lawv lub peev xwm los tiv thaiv kev tua ntawm ISOs siab dua. Yog tias koj tua ntau heev nyob rau hauv ntuj thiab tsis tshua muaj teeb, koj yuav undoubtedly pom qhov no pab tau. Cov neeg uas tua toj roob hauv pes thiab architectural photography kuj yuav xav mus saib tag nrho cov kev xaiv thav duab, raws li cov duab zoo thiab wide-angle lens zoo tseem nyob deb ua ntej.
Rau qhov xwm txheej, tsiaj qus, thiab cov neeg nyiam ua kis las, cov khoom siv qoob loo ua rau muaj kev nkag siab ntau dua. Koj tuaj yeem ua kom zoo dua ntawm qhov ntev focal ntev uas muaj los ntawm ntau qhov kev nthuav dav, thiab cov koob yees duab no feem ntau muaj qhov nrawm nrawm nrawm. Thaum koj yuav tau xam cov focal lengths, koj yuav tuav tus thawj aperture ntawm lub lens. Yog li, yog tias koj muaj lub lens 50mm ruaj khov, uas yog f2.8, nws yuav tuav qhov aperture txawm tias qhov loj dua mus txog 80mm.
Ob hom ntawv muaj lawv qhov zoo. Cov koob yees duab puv puv loj dua, hnyav dua, thiab kim dua. Lawv muaj ntau yam txiaj ntsig rau cov kws tshaj lij, tab sis feem ntau cov neeg yuav tsis xav tau cov yam ntxwv no tiag tiag. Tsis txhob dag los ntawm tus neeg muag khoom uas qhia koj tias koj xav tau lub koob yees duab kim heev. Tsuav koj dais ob peb lub tswv yim yooj yooj yim hauv siab, koj yuav tsum paub zoo kom xaiv qhov zoo rau koj cov kev xav tau.
