MTF (Modulation Transfer Action) jadawali mai lankwasa yana aiki azaman kayan aiki mai mahimmanci don kimanta aikin gani na ruwan tabarau. Ta hanyar ƙididdige ikon ruwan tabarau don adana bambanci a tsakanin mitoci daban-daban, yana gani yana kwatanta mahimman halaye na hoto kamar ƙuduri, daidaiton aminci, da daidaiton gefen-zuwa-banga. A ƙasa akwai cikakken bayani:
I. Fassarar Haɗa Gatura da Lanƙwasa
Horizontal Axis (Nisa Daga Cibiyar)
Wannan axis yana wakiltar nisa daga tsakiyar hoton (farawa daga 0 mm a hagu) zuwa gefen (ma'anar ƙarewa a dama), wanda aka auna a millimeters (mm). Domin cikakken-frame ruwan tabarau ya kamata a biya musamman hankali ga kewayon daga 0 zuwa 21 mm, wanda yayi daidai da rabin diagonal na firikwensin (43 mm). Don ruwan tabarau na tsarin APS-C, kewayon da ya dace yawanci ana iyakance shi zuwa 0 zuwa 13 mm, yana wakiltar tsakiyar ɓangaren hoton.
A tsaye Axis (Matsalar MTF)
Axis na tsaye yana nuna matakin da ruwan tabarau ke adana bambanci, jere daga 0 (ba a kiyaye bambanci) zuwa 1 (cikakkiyar kiyaye bambanci). Ƙimar 1 tana wakiltar kyakkyawan yanayin ka'idar da ba za a iya samu a aikace ba, yayin da ƙididdiga mafi kusa da 1 suna nuna kyakkyawan aiki.
Nau'in Maɓalli Maɓalli
Mitar sararin samaniya (Raka'a: nau'i-nau'i a kowace millimeter, lp/mm):
- Madaidaicin 10 lp/mm (wanda ke wakilta ta layin kauri) yana nuna ƙarfin haifuwa gaba ɗaya na ruwan tabarau. Ƙimar MTF sama da 0.8 ana ɗaukarta gabaɗaya tana da kyau.
- Madaidaicin 30 lp / mm (wanda ke wakilta ta layin bakin ciki) yana nuna ikon warwarewar ruwan tabarau da kaifi. Ana ɗaukar ƙimar MTF da ta wuce 0.6 a matsayin mai kyau.
Hanyar Layi:
- Layi mai ƙarfi (S / Sagittal ko Radial): Yana wakiltar layin gwaji waɗanda ke shimfiɗa radially waje daga tsakiya (misali, kama da magana akan dabaran).
- Layin Dige-dige (M / Meridional ko Tangential): Yana wakiltar layin gwaji da aka tsara a cikin da'irori (misali, alamu masu kama da zobe).
II. Ma'auni na Aiki
Tsawon Lanƙwasa
Yankin Tsakiya (Side Hagu na Horizontal Axis): Maɗaukakin ƙimar MTF don duka 10 lp / mm da 30 lp / mm masu lankwasa suna nuna mafi girman hoto na tsakiya. Babban ruwan tabarau sau da yawa cimma matsakaicin ƙimar MTF sama da 0.9.
Yankin Edge (Gefen Dama na Axis Horizontal): Ƙarƙashin ƙimar ƙimar MTF zuwa gefuna yana nuna kyakkyawan aiki na gefen. Alal misali, ƙimar MTF na gefen 30 lp / mm mafi girma fiye da 0.4 abu ne mai karɓa, yayin da fiye da 0.6 ana la'akari da kyau.
Launuka Mai Lanƙwasa
Canjin sassauƙa mai santsi tsakanin tsakiya da gefen yana ba da ƙarin daidaiton aikin hoto a cikin firam ɗin. Rage raguwar ƙima yana nuna gagarumin raguwar ingancin hoto zuwa gefuna.
Makusancin S da M Curves
Matsakaicin sagittal (layi mai ƙarfi) da meridional (layin dashe) masu lanƙwasa suna nuna kulawar astigmatism na ruwan tabarau. Matsakaicin kusanci yana haifar da ƙarin bokeh na halitta da raguwar ɓarna. Rabuwa mai mahimmanci na iya haifar da al'amura kamar numfashi mai da hankali ko kayan aikin layi biyu.
III. Ƙarin Abubuwan Tasiri
Girman Budawa
Matsakaicin Buɗawa (misali, f/1.4): Zai iya haifar da mafi girman MTF na tsakiya amma yana iya haifar da lalacewa ta gefe saboda ɓarnawar gani.
Mafi kyawun buɗewa (misali, f/8): Yawanci yana ba da ƙarin daidaiton aikin MTF a duk faɗin firam ɗin kuma galibi ana haskaka shi cikin shuɗi akan jadawali na MTF.
Canjin Lens na Zuƙowa
Don zuƙowa ruwan tabarau, MTF masu lankwasa ya kamata a kimanta daban a cikin fadi-angle da telephoto iyakar, kamar yadda yi na iya bambanta da mai da hankali tsawon.
IV. Muhimman La'akari
Iyaka na MTF Analysis
Yayin da MTF ke ba da fahimi masu mahimmanci game da ƙuduri da bambanci, ba ya lissafin wasu lahani na gani kamar murdiya, ɓarna chromatic, ko walƙiya. Waɗannan abubuwan suna buƙatar ƙarin kimantawa ta amfani da ma'auni masu dacewa.
Kwatanta Alamar Giciye
Saboda bambance-bambancen hanyoyin gwaji da ƙa'idodi a tsakanin masana'antun, ya kamata a guji kwatance kai tsaye na masu lankwasa MTF a kowane iri daban-daban.
Kwanciyar Kwanciyar Hankali da Sirri
Sauye-sauye marasa tsari ko asymmetry a cikin madaidaicin MTF na iya nuna rashin daidaiton masana'anta ko batutuwan sarrafa inganci.
Takaitacciyar Takaitawa:
Halayen Lens masu Hakuri:
- Duk 10 lp / mm kwana ya kasance sama da 0.8
- Tsakiyar 30 lp/mm ya wuce 0.6
- Edge 30 lp/mm ya wuce 0.4
– Sagittal da meridional masu lankwasa suna daidaitawa sosai
- MTF mai laushi da lalacewa a hankali daga tsakiya zuwa gefe
Mayar da hankali na Farko:
- Ƙimar 30 lp / mm ta tsakiya
- Degree na gefen MTF attenuation
- Kusanci na S da M masu lankwasa
Tsayar da kyawawa a duk fagage uku yana nuna ƙaƙƙarfan ƙira na gani da haɓaka inganci.
Lokacin aikawa: Jul-09-2025