MTF (Modulation Transfer Function) nkhaus daim duab ua haujlwm tseem ceeb hauv kev tshuaj ntsuam xyuas qhov ua tau zoo ntawm cov lo ntsiab muag. Los ntawm kev txheeb xyuas lub lens lub peev xwm los khaws qhov sib txawv ntawm qhov sib txawv ntawm qhov sib txawv, nws pom pom cov yam ntxwv tseem ceeb xws li kev daws teeb meem, qhov sib txawv ntawm kev ncaj ncees, thiab ntug-rau-ntug sib xws. Hauv qab no yog cov lus piav qhia ntxaws:
I. Kev txhais ntawm Coordinate Axes thiab Curves
Kab rov tav Axis (Nyob deb ntawm Center)
Qhov axis no sawv cev qhov kev ncua deb ntawm qhov nruab nrab ntawm daim duab (pib ntawm 0 hli ntawm sab laug) mus rau ntug (kawg taw tes rau sab xis), ntsuas hauv millimeters (mm). Rau tag nrho-ncej lo ntsiab muag, tshwj xeeb yuav tsum tau them rau qhov ntau ntawm 0 mus rau 21 hli, uas sib haum mus rau ib nrab ntawm kab pheeb ces kaum ntawm lub sensor (43 hli). Rau APS-C hom lo ntsiab muag, qhov cuam tshuam feem ntau yog txwv rau 0 txog 13 hli, sawv cev rau qhov nruab nrab ntawm lub voj voog duab.
Vertical Axis (MTF Tus Nqi)
Lub axis ntsug qhia txog qib uas lub lens khaws qhov sib txawv, xws li 0 (tsis muaj qhov sib txawv tshwj xeeb) mus rau 1 (kev txuag zoo meej). Tus nqi ntawm 1 sawv cev rau qhov zoo tshaj plaws theoretical scenario uas tsis tuaj yeem ua tiav hauv kev xyaum, thaum qhov tseem ceeb ze rau 1 qhia tau hais tias ua tau zoo dua.
Key Curve Hom
Spatial zaus (Unit: kab khub ib millimeter, lp/mm):
- Lub 10 lp / mm nkhaus (sawv cev los ntawm ib txoj kab tuab) qhia txog lub lens tag nrho qhov sib txawv ntawm kev tsim muaj peev xwm. Ib qho MTF tus nqi siab dua 0.8 feem ntau suav hais tias zoo heev.
- Lub 30 lp / mm nkhaus ( sawv cev los ntawm ib txoj kab nyias) qhia tias lub lens daws lub zog thiab qhov ntse. Tus nqi MTF tshaj 0.6 yog suav tias yog qhov zoo.
Kab lus qhia:
- Cov Kab Khoom (S / Sagittal lossis Radial): Sawv cev cov kab xeem txuas mus rau sab nraud ntawm qhov chaw (piv txwv li, zoo li cov lus ntawm lub log).
- Dotted Line (M / Meridional lossis Tangential): Sawv cev cov kab xeem uas tau teem rau hauv cov voj voog concentric (piv txwv li, cov qauv zoo li lub nplhaib).
II. Kev ntsuas kev ua tau zoo
Curve Qhov siab
Central Region (Sab laug ntawm kab rov tav axis): siab dua MTF qhov tseem ceeb rau ob qho tib si 10 lp / mm thiab 30 lp / mm curves qhia sharper central imaging. High-end lo ntsiab muag feem ntau ua tiav nruab nrab MTF qhov tseem ceeb tshaj 0.9.
Ntug cheeb tsam (Sab xis ntawm kab rov tav axis): Kev txo qis ntawm MTF qhov tseem ceeb rau cov npoo qhia qhov kev ua tau zoo ntawm ntug. Piv txwv li, ntug MTF tus nqi ntawm 30 lp / mm ntau dua 0.4 yog qhov tau, thaum tshaj 0.6 yog suav tias yog zoo heev.
Curve Smoothness
Ib qho kev hloov pauv ntawm qhov nruab nrab thiab ntug pom zoo ua kom pom kev ua tau zoo nyob thoob plaws tus ncej. Ib qho kev poob qis qhia tias qhov kev poob qis hauv cov duab zoo ntawm cov npoo.
Closeness ntawm S thiab M Curves
Qhov sib thooj ntawm sagittal (khoom khov) thiab meridional (dashed kab) nkhaus qhia txog lub lens astigmatism tswj. Kev sib raug zoo dua ua rau muaj ntau yam bokeh thiab txo qis aberrations. Kev sib cais tseem ceeb tuaj yeem ua rau muaj teeb meem xws li ua pa kom pom tseeb lossis ob kab khoom cuav.
III. Ntxiv qhov cuam tshuam
Aperture Loj
Qhov siab tshaj plaws Aperture (piv txwv li, f / 1.4): Tej zaum yuav ua rau siab dua hauv nruab nrab MTF tab sis tuaj yeem ua rau ntug degradation vim qhov pom qhov txawv txav.
Optimal Aperture (piv txwv li, f / 8): Feem ntau muaj qhov sib npaug ntawm MTF kev ua tau zoo thoob plaws tus ncej thiab feem ntau tseem ceeb hauv xiav ntawm MTF daim duab.
Zoom Lens Variability
Rau qhov zoom lo ntsiab muag, MTF curves yuav tsum tau soj ntsuam nyias ntawm lub dav-lub kaum sab xis thiab telephoto xaus, vim hais tias kev ua tau zoo yuav txawv nrog focal ntev.
IV. Kev txiav txim siab tseem ceeb
Kev txwv ntawm MTF Analysis
Thaum MTF muab kev nkag siab zoo rau kev daws teeb meem thiab qhov sib txawv, nws tsis suav rau lwm qhov tsis zoo ntawm qhov muag xws li distortion, chromatic aberration, lossis flare. Cov yam no xav tau kev ntsuam xyuas ntxiv uas siv cov ntsuas kev sib txuas.
Hla-Brand sib piv
Vim muaj kev hloov pauv hauv kev sim cov txheej txheem thiab cov qauv ntawm cov tuam txhab, kev sib piv ncaj qha ntawm MTF nkhaus hla ntau hom yuav tsum zam.
Curve Stability thiab Symmetry
Kev hloov pauv tsis tu ncua lossis asymmetry hauv MTF nkhaus tuaj yeem qhia txog kev tsim khoom tsis sib xws lossis teeb meem kev tswj kom zoo.
Cov ntsiab lus ceev:
Cov yam ntxwv ntawm High-Performance Lenses:
- Tag nrho 10 lp / mm nkhaus tseem nyob saum 0.8
- Central 30 lp / mm siab tshaj 0.6
- Ntug 30 lp / mm siab tshaj 0.4
- Sagittal thiab meridional nkhaus yog zoo sib xws
- Smooth thiab maj mam MTF lwj los ntawm nruab nrab mus rau ntug
Kev Ntsuam Xyuas Qhov Tseem Ceeb:
- Central 30 lp / mm tus nqi
- Qib ntawm ntug MTF attenuation
- Qhov sib thooj ntawm S thiab M nkhaus
Kev tuav tau zoo nyob rau hauv tag nrho peb qhov chaw qhia tau hais tias superior kho qhov muag tsim thiab tsim kom zoo.
Lub sij hawm xa tuaj: Plaub Hlis-09-2025