Yini ukubheka lapho ekhetha lens? Imbobo - omunye nemingcele ebaluleke kakhulu

Imbobo - lokhu ingenye nemingcele main ofuna ukunaka lapho ekhetha lens. Imbobo kudivayisi optical kubonisa ezingeni attenuation ka yokucucuza ukukhanya.

Ngamanye amazwi, ipharamitha kubonisa ukuthi iyiphi ingxenye yokucucuza ukukhanya odlula ngokwawo umgomo lens uhlelo. Yokucucuza ukukhanya lapho sidlula idivayisi optical kancane ehlakazekele kuvezwa lens ngokwengxenye amuncwa impahla lens akhiqizwa (plastic optical, ingilazi). Ngenxa yalokho, kungaba kakhulu buthaka ngenxa lezi nezici zabo ezingokomzimba.

Nokho, lokhu akukhona wukuphela ukuthi inquma amandla ukukhanya-kubutsela, okuyilona elidingekayo ukuze banake lapho ekhetha lens. Imbobo kudivayisi optical incike beso esiphezulu evulekile. I evulekile kakhulu beso, ukukhanya okwengeziwe engena lens. Futhi njengoba i-beso lens okuyinto f / 1.8 noma 1: 1.8, kubhekwa kabanzi njengoba kuqhathaniswa nge ephezulu beso lens, f / 2.8 noma 1: 2.8. Ngokuvamile, ukuze kube lula, lo beso ratio idivayisi optical kunqunywa ezingeni esiphezulu beso evulekile, okuvumela ukuba adalule lens. Nokho, isilinganiso beso kuyinto izakhi esingokwemvelo isici kwesakhiwo kohlelo optical futhi ukubaluleka beso diaphragm wenza kuphela eminye imisebenzi ephathelene ne-sokunquma beso ratio zedivayisi. Nokho, kusukela iphuzu eliwusizo umbono othile, kuba lula ukuqhathanisa lens ka ipharamitha we esiphezulu ukubaluleka okungenzeka beso evulekile. Ngakho iziphi le miqondo emibili kungase kubhekwe njengokwelapha ezifanayo.

I beso ratio uhlelo optical njalo kukhonjisiwe ezibekiweko of the lens esifakiwe, kodwa futhi imakwe emzimbeni zedivayisi eduze phambi lens. Ngokwesibonelo, beso lens Canon 24-70 f / 2.8. Kuyaqondakala ukuthi onjalo sokudubula lens avumele ukuvulwa kwe-beso lungene 2.8. Lokhu kusho ukuthi kudivayisi ngeke sivumele diaphragm ahlolisise 2.0, 1.8 nokunye. D.

I-lens, yona beso ivumela ngokudubula ezingeni ukubaluleka beso f / 1.2 ukuze f / 2.8, kubhekwa a ephezulu beso. Amadivayisi nge ezingeni kusukela f / 3.5 f / 6.3, alisho ephezulu beso, esivame ukubizwa ngokuthi "amnyama" njengoba edlula inani elincane ecucuza ukukhanya. Abanye abaholi ukwenziwa izinhlelo optical (isib Leica noCarl Zeiss), amadivayisi ukukhululwa iphethini nge likhanya ngendlela efanayo ezingeni kusukela f / 0.7 ukuze f / 0,95. Okuvame kakhulu ephezulu beso lens phakathi bezithombe - zingamathuluzi nge value of f / 1.4 ukuze f / 2.8.

Manje cabanga ngalokho umphumela ukubeka isilinganiso beso. Zonke izinzuzo zalezi lens abahlangene value beso. Lokhu kungenxa yokuthi uma ngokudubula beso kuthinta inani Ukudlula ukukhanya ngokusebenzisa lens kanye ukudepha kwenkundla in the ifremu. Ngakho, i-digital ikhamera lens beso kuthinta ikhono ukwenza lolu cwaningo lokungena ekukhanyeni dim. I emikhulu ukubaluleka beso, ezincane ngeke le ukudepha kwenkundla ifremu, ukuthi unamandla razmoyut izinto ningaweli endaweni focus.