UV lim yog lim ultraviolet. Nws lub hom phiaj tseem ceeb yog los tiv thaiv lub lens optical los ntawm kev puas tsuaj, plua plav thiab av (tag nrho cov no ua rau lub lens sai sai). Tsis tas li ntawd, cov khoom siv kho qhov muag no ncua sijhawm ultraviolet hluav taws xob thaum tua cov khoom nyob deb. Tom qab tag nrho, ib qho digital matrix thiab zaj duab xis, tsis zoo li tib neeg lub qhov muag, muaj kev nkag siab ntau dua rau hom hluav taws xob no. UV lim yog qhov muaj txiaj ntsig zoo thaum tua hauv toj roob hauv pes, nws pab kom tsis txhob xiav cam hauv cov duab.
Tag nrho cheeb tsam ntawm ultraviolet spectrum tuaj yeem muab faib ua 3 thaj tsam: deb - 280 nm thiab luv dua (UV-C); nruab nrab - 320-280 nm (UV-B); thiab ze - 400-320 nm (UV-A). Lub rhiab heev ntawm cov thev naus laus zis thev naus laus zis yog qis dua li cov thev naus laus zis thev naus laus zis, yog li nws lees txais qhov ze ze, thiab cov yeeb yaj kiab tuaj yeem kho tag nrho thaj tsam ntawm ultraviolet ntau yam (tab sis tib neeg lub qhov muag tsis tuaj yeem pom hauv ib qho ntawm cov kab no). Txawm li cas losQhov muaj peev xwm ntawm cov koob yees duab zaj duab xis yog txwv los ntawm qhov ua tau ntawm cov lo ntsiab muag kho qhov muag. UV lim txiav cov hluav taws xob xws li 320 nm (nruab nrab thiab nyob deb).
Thaum xaiv cov khoom lag luam zoo li no, nws yog qhov tsim nyog los tsim cov kab ntawm lub lens. Ntawd yog, txhawm rau txheeb xyuas seb lub lim dej twg haum rau koj lub koob yees duab, koj yuav tsum paub txog txoj kab uas hla ntawm lub lens xov (nws tau qhia ntawm lub hau ntawm sab hauv). Tus nqi ntawm ib yam khoom nyob ntawm nws qhov loj. Yog li 52 mm UV lim raug nqi $ 10-15, thiab 77 mm lim raug nqi $ 30-40.
Nws yog txoj cai los faib cov lim UV ua plaub pawg:
- Neutral - nruab nrab tsis muaj xim;
- SkyLight - liab, tsim los muab cov duab sov tones;
- ncaj UV - ultraviolet;
- Haze - tawm tsam haze.
Txawm hais tias muaj qhov sib txawv ntawm sab nraud, lub hom phiaj ntawm pab pawg no yog tib yam - los tiv thaiv lub lens los ntawm kev cuam tshuam sab nraud, cov xim ultraviolet thiab haze. Qhov nrov tshaj plaws yog UV lim thiab Skylight.
Feem ntau cov neeg muag khoom tam sim no Skylight yog qhov zoo tshaj plaws thiab, raws li, kim, tab sis cov nyhuv ntawm cov suab nrov sov hauv daim duab yog npaj rau cov koob yees duab yeeb yaj kiab nkaus xwb, ntawm cov digital nws raug txo kom xoom los ntawm qhov muaj qhov sib npaug dawb..
Thaum xaiv cov khoom lag luam zoo li no, tsis txhob hnov qab tias lub luag haujlwm tseem ceeb yog los tiv thaiv lub qhov muag ntawm lub lens los ntawm kev cuam tshuam ntawm cov khoom, thiab kev tiv thaiv UV thiab lwm yam yog qhov thib ob. Ntau tus kws yees duab nyiam ua yeeb yam tsis ntseeg lub peev xwm los lim cov hluav taws xob ultraviolet, vim tias hauv daim duab nws yogxyaum tsis cuam tshuam (raws li cov tuam ntxhab, lub lim tiv thaiv cov matrix digital). Raws li cov kws yees duab zoo li no, cov tuam txhab kev yees duab optics tsuas yog them nyiaj rau cov kws yees duab amateur. Yog li ntawd, nws feem ntau pom zoo tias thaum xaiv ib lossis lwm lub lim UV, nws yog raws li cov khoom ntawm kev tiv thaiv txhua yam. Txawm hais tias cov lo ntsiab muag tiv thaiv tau suav tias yog qhov pheej yig tshaj plaws, tsis txhob hnov qab tias txhua lub lens yog, ua ntej ntawm tag nrho cov, ib qho kev cuam tshuam rau kev nkag mus ntawm lub teeb, yog li nws yog qhov zoo dua los yuav cov khoom zoo li no los ntawm cov chaw tsim khoom txhim khu kev qha, ua los ntawm cov ntaub ntawv zoo nrog lub zog. Lub teeb kis tau tus mob.
Kev siv cov ntxaij lim dej UV lossis tsis yog nyob ntawm tus kws yees duab amateur txiav txim siab, tab sis nws yuav tsum tau ntsuas los tiv thaiv lub lens, vim tias tus nqi ntawm lub tshuab kho qhov muag zoo tuaj yeem siab dua tus nqi ntawm lub koob yees duab nws tus kheej..
