{"id":5670,"date":"2016-04-21T15:18:17","date_gmt":"2016-04-21T14:18:17","guid":{"rendered":"https:\/\/www.fotolab.cz\/blog\/?p=5670"},"modified":"2016-04-22T09:59:16","modified_gmt":"2016-04-22T08:59:16","slug":"jak-na-video","status":"publish","type":"post","link":"https:\/\/www.fotolab.cz\/blog\/jak-na-video\/","title":{"rendered":"Jak na video?\u00a0Videokamera nebo fotoapar\u00e1t?"},"content":{"rendered":"

Dne\u0161n\u00ed doba nab\u00edz\u00ed velice \u0161irok\u00e9 spektrum p\u0159\u00edstroj\u016f, kter\u00fdmi lze po\u0159\u00eddit velice zaj\u00edmav\u00e9 a kvalitn\u00ed videoz\u00e1znamy. Jak\u00e9 jsou v\u0161ak v\u00fdhody r\u016fzn\u00fdch p\u0159\u00edstroj\u016f a \u010d\u00edm se od sebe li\u0161\u00ed?<\/strong><\/p>\n

Ohl\u00e9dneme-li se n\u011bkolik let zp\u00e1tky, v\u00fdb\u011br byl daleko jednodu\u0161\u0161\u00ed.\u00a0 V minulosti\u00a0 z\u00e1kazn\u00edci vyb\u00edrali na z\u00e1klad\u011b typu kazet, kter\u00e9 se vkl\u00e1dali do videokamery<\/strong>, v\u00fddr\u017ee baterie<\/strong> nebo dle hmotnosti kamery.<\/strong><\/p>\n

Sou\u010dasn\u00e1 situace na trhu, kter\u00fd nab\u00edz\u00ed t\u00e9m\u011b\u0159 v\u0161e,<\/strong> co si \u010dlov\u011bk m\u016f\u017ee p\u0159\u00e1t a v\u00a0r\u016fzn\u00fdch cenov\u00fdch relac\u00edch, je pro z\u00e1kazn\u00edka mnohem zr\u00e1dn\u011bj\u0161\u00ed. Parametry p\u0159\u00edstroj\u016f jsou daleko vysp\u011blej\u0161\u00ed<\/strong>, ne\u017e v\u00a0d\u0159\u00edv\u011bj\u0161\u00edch letech a proto je nutn\u00e9 v\u00edce studovat a zaj\u00edmat se, co vlastn\u011b kter\u00e1 funkce um\u00ed, znamen\u00e1 a pro\u010d tomu tak vlastn\u011b je. Neopom\u00ednejme software, tak i hardware v\u00fdbavu.<\/p>\n

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Zam\u011b\u0159me se na v\u00fdb\u011br apar\u00e1t\u016f podle pot\u0159eb z\u00e1kazn\u00edka<\/strong> a po\u017eadavk\u016f na videoz\u00e1znam. Jedn\u00edm z hlavn\u00edch parametr\u016f je velikost a typ sn\u00edma\u010de (\u010dipu).<\/strong><\/p>\n

P\u0159i v\u00fdb\u011bru p\u0159\u00edstroje je nutn\u00e9 zohlednit velikost obrazov\u00e9ho sn\u00edma\u010de<\/strong>, jeliko\u017e ta rovn\u011b\u017e ovliv\u0148uje fin\u00e1ln\u00ed v\u00fdsledky obrazu. Rozm\u011br \u010dipu op\u011bt pozitivn\u011b ovliv\u0148uje hladinu \u0161umu a sou\u010dasn\u011b tak\u00e9 ovliv\u0148uje pom\u011br a m\u00edru hloubky ostrosti.<\/p>\n

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Obecn\u011b sn\u00edma\u010d p\u0159ev\u00e1d\u00ed sv\u011btlo do digit\u00e1ln\u00edho sign\u00e1lu<\/strong>.\u00a0Typ<\/strong> sn\u00edma\u010de CCD<\/strong> najdeme sp\u00ed\u0161e u levn\u011bj\u0161\u00edch za\u0159\u00edzen\u00ed, zat\u00edmco typ CMOS<\/strong> je pou\u017e\u00edv\u00e1n ve vy\u0161\u0161\u00edch modelech apar\u00e1t\u016f s\u00a0vy\u0161\u0161\u00ed cenou. Tento typ je v\u00edce preferov\u00e1n z\u00e1kazn\u00edky z\u00a0d\u016fvodu vy\u0161\u0161\u00ed citlivosti v\u00a0hor\u0161\u00edch sv\u011bteln\u00fdch podm\u00ednk\u00e1ch, co\u017e sni\u017euje hladinu digit\u00e1ln\u00edho \u0161umu<\/strong>. Nav\u00edc CMOS<\/strong> technologie \u010dip\u016f umo\u017e\u0148uje nat\u00e1\u010det videosekvence ve FullHD rozli\u0161en\u00ed, co\u017e CCD sn\u00edma\u010de neumo\u017e\u0148uj\u00ed<\/strong>.<\/span><\/em><\/p>\n<\/blockquote>\n

Zejm\u00e9na pro z\u00e1znam videosekvenc\u00ed je dobr\u00e9 zohlednit p\u0159i v\u00fdb\u011bru typ stabilizace. V\u017edy je lep\u0161\u00ed zvolit mechanickou<\/strong>, nebo tak\u00e9 optickou<\/strong> stabilizaci<\/strong> p\u0159ed verz\u00ed digit\u00e1ln\u00ed<\/strong>.\u00a0<\/p>\n

Z\u00e1m\u011br nejen u fotografi\u00ed ale i u videoz\u00e1znamu je m\u00edt obraz zcela ostr\u00fd.<\/strong> U ost\u0159en\u00ed m\u016f\u017eeme pozorovat v\u00fdrazn\u00fd rozd\u00edl mezi b\u011b\u017en\u00fdmi fotoapar\u00e1ty a kamerami, kter\u00e9 se vyu\u017e\u00edvaj\u00ed v\u00fdhradn\u011b na z\u00e1znam videosekvenc\u00ed<\/strong>. Nicm\u00e9n\u011b nejen rychlost ost\u0159en\u00ed je d\u016fle\u017eit\u00e1. Mus\u00edme vz\u00edt v \u00favahu i p\u0159esnost ost\u0159en\u00ed<\/strong>.<\/p>\n

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\"posuv-snimace\"<\/div>\n<\/div>\n
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Jak to funguje? Princip digit\u00e1ln\u00ed stabilizace se zakl\u00e1d\u00e1 na o\u0159ez\u00e1v\u00e1n\u00ed obrazu<\/strong>, co\u017e dle m\u00e9ho m\u00edn\u011bn\u00ed ur\u010dit\u011b nen\u00ed \u017e\u00e1douc\u00ed v\u011bc, p\u0159edev\u0161\u00edm u nat\u00e1\u010den\u00ed videa. Mechanickou stabilizaci m\u00e1me ve dvou form\u00e1ch proveden\u00ed. Optick\u00e1 stabilizace stabilizuje optickou soustavu<\/strong> apar\u00e1tu. Druh\u00e1 mo\u017enost je stabilizace sn\u00edma\u010de<\/strong>. Zaj\u00edmav\u00fd typ stabilizace je 5-ti os\u00fd stabiliz\u00e1tor<\/strong> ve vybran\u00fdch p\u0159\u00edstroj\u00edch nap\u0159. zna\u010dky Olympus<\/strong> nebo tzv. BOS \u2013Balanced Optical Stabilization stabiliz\u00e1tor u zna\u010dky SONY<\/strong>.<\/em><\/span><\/p>\n<\/blockquote>\n

U videokamer je p\u0159eost\u0159ov\u00e1n\u00ed na r\u016fzn\u00e9 objekty nebo p\u0159i p\u0159ibli\u017eov\u00e1n\u00ed zcela b\u011b\u017en\u00e9<\/strong>. U fotoapar\u00e1t\u016f je to s p\u0159eost\u0159ov\u00e1n\u00edm mezi r\u016fzn\u00fdmi vzd\u00e1lenostmi nebo objekty v\u00fdrazn\u011b hor\u0161\u00ed. Fotoapar\u00e1ty jsou dimenzovan\u00e9 k\u00a0velmi rychl\u00e9mu jednor\u00e1zov\u00e9mu ost\u0159en\u00ed p\u0159i fotografov\u00e1n\u00ed, nikoli p\u0159i po\u0159izov\u00e1n\u00ed videoz\u00e1znamu<\/strong>.<\/p>\n