Polarizer.QUOTE
There are two types of polarizing filters. A linear polarizer filter transmits one of two states of linearly polarized light. A circular polarizer (sometimes called a CPL filter) similarly selects a linear state but then converts it to circularly polarized light, by adding a birefringent layer (typically a quarter-wave plate) to the filter after the linear polarizer.
The metering and auto-focus sensors in certain cameras, including virtually all SLRs, will not work properly with linear polarizers, both because of the mirror and because of the beam-splitters used to split off the light for focusing and metering. Circular polarizers will work with all types of cameras.
Deci practic, un polarizator circular este in esenta un polarizator liniar la care i se adauga dupa filtrare un strat sfert-de-unda pentru schimbarea polarizarii in "circulara". De fapt asta insemna "distrugerea" polarizarii lumini dupa filtrare (si-a facut treaba, a filtrat lumina polarizata incidenta, la iesire nu mai este nevoie sa ramana polarizata dupa un anume plan) pentru a nu afecta sistemele de focus si masura din camerele SRL (digitale sau cele cu film si AE si/sau AF ca cele din seria Maxxum Minolta).
La camere P&S care nu au oglinzi sau beam-splittere nu conteaza daca filtrul este liniar sau circular.
Acest mesaj a fost modificat de SuperDuper: 8th July 2007, 21:21