{"id":67373,"date":"2020-01-28T11:49:06","date_gmt":"2020-01-28T10:49:06","guid":{"rendered":"https:\/\/tipyjakfotit.cz\/?p=67373"},"modified":"2020-01-28T12:05:48","modified_gmt":"2020-01-28T11:05:48","slug":"front-back-focus","status":"publish","type":"post","link":"https:\/\/tipyjakfotit.cz\/front-back-focus\/","title":{"rendered":"Tipy jak zjistit vadu objektivu – front a back focus"},"content":{"rendered":"

Napadlo v\u00e1s n\u011bkdy, \u017ee to, pro\u010d jsou va\u0161e fotografie neostr\u00e9, m\u016f\u017ee b\u00fdt ve skute\u010dnosti kv\u016fli va\u0161emu objektivu?\u00a0<\/span><\/p>\n

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Neexistuje nic v\u00edc frustruj\u00edc\u00edho, ne\u017e kdy\u017e tr\u00e1v\u00edte \u010das nad focen\u00edm skv\u011bl\u00e9 fotografie, ale vyleze z toho n\u011bco, co nen\u00ed v\u016fbec ostr\u00e9. Tak\u017ee pokud m\u00e1te pocit, \u017ee to m\u016f\u017ee b\u00fdt va\u0161im objektivem, m\u016f\u017eete n\u011bco zkusit: otestujte si sv\u00e9 objektivy, aby jste zjistili, jestli ost\u0159\u00ed na to m\u00edsto, na kter\u00e9 by ost\u0159it m\u011bly.\u00a0<\/span><\/p>\n

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Tento test v\u00e1m uk\u00e1\u017ee, \u017ee v\u0161e funguje spr\u00e1vn\u011b. V nejhor\u0161\u00edm p\u0159\u00edpad\u011b v\u00e1s upozorn\u00ed na probl\u00e9m, kter\u00fd je na \u010dase vy\u0159e\u0161it!<\/span><\/p>\n

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Tak\u017ee a\u017e budete p\u0159ipraveni, pus\u0165te se do toho!:)<\/span><\/p>\n

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\"lens\"<\/p>\n

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\n

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Co je back \/ front focus?<\/span><\/h2>\n

Je to jednoduch\u00e9: Pokud je sn\u00edmek ostr\u00fd P\u0158ED, neboli pod m\u00edstem, kam jste ost\u0159ili, jedn\u00e1 se o vadu front focus. Pokud je ale sn\u00edmek zaost\u0159en\u00fd ZA \/ nad m\u00edstem, kam jste ost\u0159ili, \u0159\u00edk\u00e1 se tomu back focus. V obou p\u0159\u00edpadech je m\u00edsto, na kter\u00e9 jste ost\u0159ili, lehce neostr\u00e9, ale m\u00edsto nad nebo pod je ostr\u00e9.<\/p>\n

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Tak\u017ee, te\u010f v\u00e1m spr\u00e1vn\u011b do\u0161lo, \u017ee ve v\u011bt\u0161in\u011b p\u0159\u00edpad\u016f se st\u00e1le jedn\u00e1 o chybu u\u017eivatele.<\/strong><\/p>\n

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Pokud fot\u00edte na otev\u0159enou clonu a dr\u017e\u00edte fo\u0165\u00e1k v rukou a nem\u00e1te ho na stativu, i va\u0161e d\u00fdch\u00e1n\u00ed m\u016f\u017ee\u00a0m\u00edt dopad na front nebo back focus. Ale i p\u0159i vy\u0161\u0161\u00edch clonov\u00fdch \u010d\u00edslech v\u011bt\u0161ina lid\u00ed pou\u017e\u00edv\u00e1 \u0161patn\u00e9 zaost\u0159ovac\u00ed techniky nebo re\u017eimy\u00a0na to, co pr\u00e1v\u011b fot\u00ed. Pr\u00e1v\u011b to zp\u016fsobuje, \u017ee va\u0161e fotografie nejsou tak ostr\u00e9, jak byste si p\u0159\u00e1li.\u00a0<\/p>\n

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Jin\u00fdmi slovy se tato vada d\u00e1 opravit pouh\u00fdm u\u010den\u00edm se o t\u011bchto v\u011bcech, proto\u017ee (bohu\u017eel) probl\u00e9m m\u016f\u017ee b\u00fdt pr\u00e1v\u011b ve v\u00e1s a ne ve va\u0161em objektivu. To ale neplat\u00ed v ka\u017ed\u00e9m p\u0159\u00edpad\u011b.:)<\/p>\n

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\"objektiv\"<\/p>\n

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Pokud je chyba opravdu ve va\u0161em za\u0159\u00edzen\u00ed, d\u00e1 se to opravit.\u00a0<\/strong><\/p>\n

Je pot\u0159eba v\u00e1\u0161 fotoapar\u00e1t s objektivem „zkalibrovat“ – pot\u0159ebuj\u00ed se vz\u00e1jemn\u011b zarovnat na spr\u00e1vn\u00e9m zaost\u0159ovac\u00edm m\u00edst\u011b.<\/p>\n

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Pro\u010d se to v\u016fbec st\u00e1v\u00e1?<\/p>\n

Ka\u017ed\u00fd fotoapar\u00e1t i objektiv je vyroben\u00fd s ur\u010dit\u00fdm rozsahem p\u0159esnosti. Tak\u017ee nap\u0159\u00edklad, v\u00e1\u0161 fo\u0165\u00e1k m\u016f\u017ee m\u00edt back focus dost\u00a0nepatrn\u00fd, jen v p\u0159ijateln\u00e9m rozp\u011bt\u00ed. V p\u0159\u00edpad\u011b objektivu to m\u016f\u017ee b\u00fdt stejn\u00e9 – tak\u00e9 m\u016f\u017ee m\u00edt nepatrn\u00fd back nebo front focus, ale po\u0159\u00e1d by to m\u011blo b\u00fdt p\u0159ijateln\u00e9.\u00a0<\/p>\n

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Ale v\u011bt\u0161inou, kdy\u017e d\u00e1te tyto dv\u011b v\u011bci dohromady, m\u016f\u017ee to b\u00fdt i mimo hranice p\u0159ijateln\u00e9ho. Sp\u00ed\u0161 to m\u016f\u017ee b\u00fdt docela velk\u00fd probl\u00e9m. Kdy\u017e tyto dv\u011b v\u011bci nepou\u017e\u00edv\u00e1te dohromady, probl\u00e9m to samoz\u0159ejm\u011b nen\u00ed. Kdy\u017e ale objektiv nasad\u00edte na t\u011blo se stejn\u00fdm probl\u00e9mem, samoz\u0159ejm\u011b se tento probl\u00e9m zv\u011bt\u0161\u00ed.\u00a0<\/p>\n

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To je tak\u00e9 d\u016fvod, pro\u010d jeden objektiv m\u016f\u017ee b\u00fdt na jednom t\u011ble perfektn\u00ed a na jin\u00e9m „mimo“.\u00a0<\/p>\n

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Co pot\u0159ebujete na front \/ back focusing test?<\/span><\/h2>\n

Tak\u017ee te\u010f, kdy u\u017e v\u00edme, co to vlastn\u011b znamen\u00e1, jak zjist\u00edme, jestli je n\u00e1\u0161 objektiv i s t\u011blem „zdrav\u00fd“?<\/p>\n

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M\u016f\u017eete si ud\u011blat n\u011bkolik test\u016f, kter\u00e9 vy\u017eaduj\u00ed nakupov\u00e1n\u00ed nebo stahov\u00e1n\u00ed\u00a0graf\u016f. St\u00e1hnout si ho m\u016f\u017eete zde a nebo si na internetu m\u016f\u017eete naj\u00edt podobnou p\u0159edlohu.<\/p>\n

\"focus<\/p>\n

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Vytiskn\u011bte si ho na A4 a testujte. N\u00ed\u017ee najdete podrobn\u00fd popis jak postupovat v tomhle, i v dal\u0161\u00edm p\u0159\u00edpad\u011b.<\/p>\n

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Je tu je\u0161t\u011b jedna mo\u017enost bez stahov\u00e1n\u00ed a nakupov\u00e1n\u00ed. Je jednoduch\u00e1 a stejn\u011b tak v\u00e1m \u0159ekne, jestli je zde n\u011bjak\u00fd probl\u00e9m.\u00a0<\/p>\n

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Budete pot\u0159ebovat:<\/strong><\/p>\n

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