Cach chon may quay phim ky thuat so

Ong kinh la yeu to duoc xem xet dau tien

Hien nay tren thi truong co ban rat nhieu loai may quay phim ky thuat so (KTS). Tuy nhien ban can chu y mot so chi tiet ky thuat de co the chon cho minh mot chiec vua dat muc dich su dung va vua voi tui tien cua ban.

Ong kinh

He thong ong kinh la bo phan dau tien cua may quay tiep nhan anh sang va hinh anh. Chat luong ong kinh duoc quyet dinh boi cong nghe va truyen thong cua cac nha san xuat ong kinh tren the gioi, day la yeu to quan trong cho chat luong thu hinh.

Ngoai su phu thuoc vao cong nghe san xuat cac thau kinh, ong kinh may quay con phai dap ung mot so nhu cau sau:

- Kha nang dong mo va do ben co hoc cua man chap, khau do, tieu cu va kha nang tang sang dien tu (Gain) de co the thu hinh o ngay ca trong moi truong anh sang yeu.

- Kha nang cua do mo goc rong va do phong dai cua ong kinh co dap ung nhu cau khi thu hinh trong cong viec cua ban.

- Ngoai cac yeu to tren con mot van de nua khong kem phan quan trong do la cong nghe che tao he thong thau kinh chong rung (OIS) cua nha san xuat, giup cho nguoi su dung may quay KTS thu duoc nhung hinh anh do net cao.

Chip xu ly hinh anh

Neu co dieu kien ban nen mua loai may co 3 chip xu ly hinh anh

Kich thuoc cua chip xu ly anh sang duoc nhan biet qua cac chi so: 1-inch, 3/4-inch, 2/3-inch 1/2-inch, 1/3-inch, 1/4-inch va 1/6 inch (1-inch tuong duong 25mm). Khi kich thuoc cua chip cang lon kha nang xu ly anh sang cang chinh xac.

Cac may quay KTS chuyen dung cho cac phim truong va dai truyen hinh su dung chip tu 2/3-inch den 1-inch nhu DVCam cua Sony hay DVCPro cua Panasonic. Loai chip co kich thuoc 1/3 va 1/4-inch duoc trang bi cho cac may quay nhu: AG-DVC30, AG-DVC60 va AG-DVX100 cua Panasonic hay DCR-VX2100, DSR-PD170 cua Sony voi gia thanh tu 2.000 USD den 4.000USD. Con nhung CCD nho hon duoc trang bi cho cac dong may quay KTS gia dinh.

Thong so thu hai cung khong kem phan quan trong, do la xu ly anh sang bang 1 chip(1CCD) hay 3 chip (3CCD). May quay phim KTS phan tich anh sang thong qua ba mau co ban la: mau do, mau xanh la cay va xanh da troi. May quay phim 1CCD phan tich anh sang 3 mau sac tren chi bang 1 chip do do chat luong mau sac hinh anh chua cao.

Con dong san pham may quay 3CCD phan tich anh sang bang 3, voi moi chip xu ly rieng biet mot mau khac nhau. Nen cac dong san pham may quay phim 3CCD cho chat luong hinh anh ro, dep hon nhieu so voi dong may quay 1CCD.

Mot so may quay KTS duoc trang bi 3CCD (1/3-inch) the he moi loai progesssive 470.000 diem anh, giong nhu cac CCD trong cac may quay chuyen dung trong nganh truyen hinh. Nen rat nhay sang co the thu hinh ngay ca khi anh sang yeu duoi 3 Lux.

Rieng cac may quay KTS cua hang Panasonic con duoc trang bi bo xu ly RGB Gamma. Ky thuat nay giup chung ta de dang thu hinh khi quay nguoc sang va hinh anh thu duoc co tone mau giong phim nhua hon cac may quay cung loai.

Bo chuyen doi A/D (chuyen tin hieu tu Analog sang ky thuat so)

Sau khi anh sang duoc phan tich qua cac chip xu ly anh sang se duoc chip A/D xu ly, chuyen doi tu tin hieu tuong tu sang tin hieu so. Chi so bit cua chip A/D lon cho chat luong cua hinh anh duoc ghi hinh tren bang DV cang cao. Day la mot yeu to quan trong va can thiet khi chon mua may quay KTS.

Cac yeu to khac

- Can bang trang, can bang den, nhanh va chinh xac. Dieu nay giup may quay ghi lai hinh anh co mau sac dep va trung thuc hon.

- Xu ly anh sang, mau sac, do net nhanh giup cho thao tac de dang khi quay.

- Cac nut dieu khien, can bang trang, khau do, toc do, tieu cu… duoc thiet ke nhu the nao de nguoi cam may tien dung khi thao tac.

- Chat luong, do ben cua cac he thong co, dau tu cua may cung nhu thoi gian hoat dong cua pin se la mot yeu to kha quan trong khi chon mua may.

- Khong nen chon cac loai may co cung luc 2 chuc nang, vua quay phim vua chup anh. Vi khi lam song song hai nhiem vu, thi muc dich chinh la ghi hinh se bi giam chat luong.

- Nen chon mua cac san pham duoc cung cap boi nhung cong ty la nha phan phoi chinh thuc.

PHAM HOAI NAM