{"id":1449,"date":"2017-11-20T16:43:47","date_gmt":"2017-11-20T14:43:47","guid":{"rendered":"https:\/\/lempea.fi\/vkperus\/?p=1449"},"modified":"2026-01-19T16:43:23","modified_gmt":"2026-01-19T14:43:23","slug":"kohinatesti","status":"publish","type":"post","link":"https:\/\/lempea.fi\/vkperus\/kohinatesti\/","title":{"rendered":"Kohinatesti"},"content":{"rendered":"<ul>\n<li>\n<h1 data-start=\"208\" data-end=\"248\">Kohinatesti (JPEG)<\/h1>\n<p data-start=\"250\" data-end=\"485\">T\u00e4ll\u00e4 testill\u00e4 selvit\u00e4t, milt\u00e4 kamerasi <strong data-start=\"290\" data-end=\"304\">JPEG-j\u00e4lki<\/strong> n\u00e4ytt\u00e4\u00e4 eri ISO-arvoilla. T\u00e4m\u00e4 on k\u00e4yt\u00e4nn\u00f6nl\u00e4heinen testi, koska JPEG-kuvaajana lopputulos syntyy kamerassa: kohina, ter\u00e4v\u00f6itys ja kohinanpoisto vaikuttavat kaikki kuvan ilmeeseen.<\/p>\n<h2 data-start=\"487\" data-end=\"497\">Tavoite<\/h2>\n<p data-start=\"498\" data-end=\"567\">Pid\u00e4 kuvaustilanne ja kuvan kirkkaus mahdollisimman samana, ja katso:<\/p>\n<ul data-start=\"568\" data-end=\"649\">\n<li data-start=\"568\" data-end=\"598\">\n<p data-start=\"570\" data-end=\"598\">milloin kohina alkaa h\u00e4irit\u00e4<\/p>\n<\/li>\n<li data-start=\"599\" data-end=\"649\">\n<p data-start=\"601\" data-end=\"649\">milloin kohinanpoisto alkaa sy\u00f6d\u00e4 yksityiskohtia<\/p>\n<\/li>\n<\/ul>\n<h2 data-start=\"651\" data-end=\"663\">Tarvitset<\/h2>\n<ul data-start=\"664\" data-end=\"851\">\n<li data-start=\"664\" data-end=\"686\">\n<p data-start=\"666\" data-end=\"686\">Kamera ja objektiivi<\/p>\n<\/li>\n<li data-start=\"687\" data-end=\"707\">\n<p data-start=\"689\" data-end=\"707\">Jalusta (suositus)<\/p>\n<\/li>\n<li data-start=\"708\" data-end=\"748\">\n<p data-start=\"710\" data-end=\"748\">Tasainen valaistus (mieluiten sis\u00e4ll\u00e4)<\/p>\n<\/li>\n<li data-start=\"749\" data-end=\"851\">\n<p data-start=\"751\" data-end=\"851\">Kohde, jossa on sek\u00e4 tummia alueita ett\u00e4 yksityiskohtia (esim. kirjahylly, kangas, puupinta + varjo)<\/p>\n<\/li>\n<\/ul>\n<hr data-start=\"853\" data-end=\"856\" \/>\n<h2 data-start=\"858\" data-end=\"896\">1) Vakioi asetukset (t\u00e4rkein vaihe)<\/h2>\n<p data-start=\"897\" data-end=\"931\">Pid\u00e4 n\u00e4m\u00e4 samana koko testin ajan:<\/p>\n<ul data-start=\"933\" data-end=\"1279\">\n<li data-start=\"933\" data-end=\"956\">\n<p data-start=\"935\" data-end=\"956\"><strong data-start=\"935\" data-end=\"951\">Kuvausmuoto:<\/strong> JPEG<\/p>\n<\/li>\n<li data-start=\"957\" data-end=\"1035\">\n<p data-start=\"959\" data-end=\"1035\"><strong data-start=\"959\" data-end=\"974\">Kuvaustila:<\/strong> suositus <strong data-start=\"984\" data-end=\"989\">M<\/strong> (manuaali). Av\/A k\u00e4y, jos M tuntuu vaikealta.<\/p>\n<\/li>\n<li data-start=\"1036\" data-end=\"1088\">\n<p data-start=\"1038\" data-end=\"1088\"><strong data-start=\"1038\" data-end=\"1048\">Aukko:<\/strong> esim. f\/5.6\u2013f\/8 (sama koko sarjan ajan)<\/p>\n<\/li>\n<li data-start=\"1089\" data-end=\"1159\">\n<p data-start=\"1091\" data-end=\"1159\"><strong data-start=\"1091\" data-end=\"1110\">Valkotasapaino:<\/strong> kiinte\u00e4 (ei AWB), esim. P\u00e4iv\u00e4nvalo \/ Hehkulamppu<\/p>\n<\/li>\n<li data-start=\"1160\" data-end=\"1233\">\n<p data-start=\"1162\" data-end=\"1233\"><strong data-start=\"1162\" data-end=\"1176\">Tarkennus:<\/strong> tarkenna kerran ja vaihda <strong data-start=\"1203\" data-end=\"1209\">MF<\/strong> (ettei tarkennus muutu)<\/p>\n<\/li>\n<li data-start=\"1234\" data-end=\"1279\">\n<p data-start=\"1236\" data-end=\"1279\"><strong data-start=\"1236\" data-end=\"1252\">Kuvanvakain:<\/strong> pois jalustalla (OIS\/IBIS)<\/p>\n<\/li>\n<\/ul>\n<h3 data-start=\"1281\" data-end=\"1343\">JPEG-kuvaajille erityisen t\u00e4rke\u00e4\u00e4: kytke varjokorjaus pois<\/h3>\n<p data-start=\"1344\" data-end=\"1430\">Monissa kameroissa on automatiikka, joka nostaa varjoja ja muuttaa kohinan n\u00e4kyvyytt\u00e4:<\/p>\n<ul data-start=\"1431\" data-end=\"1583\">\n<li data-start=\"1431\" data-end=\"1463\">\n<p data-start=\"1433\" data-end=\"1463\">Canon: Auto Lighting Optimizer<\/p>\n<\/li>\n<li data-start=\"1464\" data-end=\"1490\">\n<p data-start=\"1466\" data-end=\"1490\">Nikon: Active D-Lighting<\/p>\n<\/li>\n<li data-start=\"1491\" data-end=\"1502\">\n<p data-start=\"1493\" data-end=\"1502\">Sony: DRO<\/p>\n<\/li>\n<li data-start=\"1503\" data-end=\"1583\">\n<p data-start=\"1505\" data-end=\"1583\">Panasonic: i.Dynamic<br data-start=\"1525\" data-end=\"1528\" \/>Aseta n\u00e4m\u00e4 <strong data-start=\"1539\" data-end=\"1546\">Off<\/strong>, jotta kuvat ovat vertailukelpoisia.<\/p>\n<\/li>\n<\/ul>\n<h3 data-start=\"1585\" data-end=\"1613\">Pid\u00e4 kuvaprofiili samana<\/h3>\n<ul data-start=\"1614\" data-end=\"1763\">\n<li data-start=\"1614\" data-end=\"1700\">\n<p data-start=\"1616\" data-end=\"1700\"><strong data-start=\"1616\" data-end=\"1669\">Picture Style \/ Creative Style \/ Film Simulation:<\/strong> valitse yksi ja pid\u00e4 se samana<\/p>\n<\/li>\n<li data-start=\"1701\" data-end=\"1763\">\n<p data-start=\"1703\" data-end=\"1763\">\u00c4l\u00e4 s\u00e4\u00e4d\u00e4 ter\u00e4v\u00f6ityst\u00e4\/kontrastia\/saturaatiota kesken testin<\/p>\n<\/li>\n<\/ul>\n<hr data-start=\"1765\" data-end=\"1768\" \/>\n<h2 data-start=\"1770\" data-end=\"1819\">2) ISO-sarja (ilman valmista sekuntitaulukkoa)<\/h2>\n<p data-start=\"1820\" data-end=\"1949\">Kuvaa samasta kohtauksesta ISO-arvoilla:<br \/>\n<strong data-start=\"1861\" data-end=\"1907\">100 \u2013 200 \u2013 400 \u2013 800 \u2013 1600 \u2013 3200 \u2013 6400<\/strong><br data-start=\"1907\" data-end=\"1910\" \/>(ja 12800, jos k\u00e4yt\u00e4t sit\u00e4 k\u00e4yt\u00e4nn\u00f6ss\u00e4) tai kamerasi suurimmasta ISO arvosta<\/p>\n<\/li>\n<li>\n<p data-start=\"1820\" data-end=\"1949\">Suositus: M-tila (helppo logiikka)<\/p>\n<ol data-start=\"1990\" data-end=\"2172\">\n<li data-start=\"1990\" data-end=\"2066\">\n<p data-start=\"1993\" data-end=\"2066\">Aseta ISO 400 tai ISO 800 ja s\u00e4\u00e4d\u00e4 suljinaika niin, ett\u00e4 valotus on hyv\u00e4.<\/p>\n<\/li>\n<li data-start=\"2067\" data-end=\"2119\">\n<p data-start=\"2070\" data-end=\"2119\">Kun ISO <strong data-start=\"2078\" data-end=\"2092\">tuplaantuu<\/strong>, suljinaika <strong data-start=\"2105\" data-end=\"2118\">puolittuu<\/strong>.<\/p>\n<\/li>\n<li data-start=\"2120\" data-end=\"2172\">\n<p data-start=\"2123\" data-end=\"2172\">Kun ISO <strong data-start=\"2131\" data-end=\"2144\">puolittuu<\/strong>, suljinaika <strong data-start=\"2157\" data-end=\"2171\">tuplaantuu<\/strong>.<\/p>\n<\/li>\n<\/ol>\n<h3 data-start=\"2174\" data-end=\"2206\">Av\/A-tila (jos M on hankala)<\/h3>\n<ul data-start=\"2207\" data-end=\"2376\">\n<li data-start=\"2207\" data-end=\"2261\">\n<p data-start=\"2209\" data-end=\"2261\">Pid\u00e4 aukko samana ja anna kameran valita suljinaika.<\/p>\n<\/li>\n<li data-start=\"2262\" data-end=\"2376\">\n<p data-start=\"2264\" data-end=\"2376\">Tarkista, ett\u00e4 kuvan kirkkaus pysyy suunnilleen samana. Jos valotus heittelee, testist\u00e4 tulee vaikeampi tulkita.<\/p>\n<\/li>\n<\/ul>\n<hr data-start=\"2378\" data-end=\"2381\" \/>\n<h1 data-start=\"2383\" data-end=\"2438\">Testi 1: Nopea yhden sarjan testi (suositus kaikille)<\/h1>\n<p data-start=\"2439\" data-end=\"2491\">Tee yksi ISO-sarja kameran normaaleilla asetuksilla.<\/p>\n<ul data-start=\"2493\" data-end=\"2662\">\n<li data-start=\"2493\" data-end=\"2568\">\n<p data-start=\"2495\" data-end=\"2568\"><strong data-start=\"2495\" data-end=\"2527\">High ISO NR \/ kohinanpoisto:<\/strong> j\u00e4t\u00e4 oletukselle (esim. Normal\/Standard)<\/p>\n<\/li>\n<li data-start=\"2569\" data-end=\"2662\">\n<p data-start=\"2571\" data-end=\"2662\"><strong data-start=\"2571\" data-end=\"2592\">Long exposure NR:<\/strong> voit j\u00e4tt\u00e4\u00e4 oletukselle tai pois, mutta v\u00e4lt\u00e4 hyvin pitki\u00e4 valotuksia<\/p>\n<\/li>\n<\/ul>\n<p data-start=\"2664\" data-end=\"2707\">T\u00e4m\u00e4 kertoo, millaista j\u00e4lke\u00e4 saat arjessa.<\/p>\n<hr data-start=\"2709\" data-end=\"2712\" \/>\n<h1 data-start=\"2714\" data-end=\"2782\">Testi 2: Opetuksellinen vertailu (kohinanpoisto vs yksityiskohdat)<\/h1>\n<p data-start=\"2783\" data-end=\"2820\">Tee kaksi ISO-sarjaa ja vertaa niit\u00e4:<\/p>\n<p data-start=\"2822\" data-end=\"2833\"><strong data-start=\"2822\" data-end=\"2833\">Sarja A<\/strong><\/p>\n<ul data-start=\"2834\" data-end=\"2868\">\n<li data-start=\"2834\" data-end=\"2868\">\n<p data-start=\"2836\" data-end=\"2868\">High ISO NR: <strong data-start=\"2849\" data-end=\"2868\">Normal\/Standard<\/strong><\/p>\n<\/li>\n<\/ul>\n<p data-start=\"2870\" data-end=\"2881\"><strong data-start=\"2870\" data-end=\"2881\">Sarja B<\/strong><\/p>\n<ul data-start=\"2882\" data-end=\"2945\">\n<li data-start=\"2882\" data-end=\"2945\">\n<p data-start=\"2884\" data-end=\"2945\">High ISO NR: <strong data-start=\"2897\" data-end=\"2904\">Off<\/strong> (tai Low, jos Off n\u00e4ytt\u00e4\u00e4 liian rajulta)<\/p>\n<\/li>\n<\/ul>\n<p data-start=\"2947\" data-end=\"2998\">Molemmissa sarjoissa pid\u00e4 kaikki muu t\u00e4ysin samana.<\/p>\n<p data-start=\"3000\" data-end=\"3029\">T\u00e4m\u00e4 n\u00e4ytt\u00e4\u00e4 konkreettisesti:<\/p>\n<ul data-start=\"3030\" data-end=\"3112\">\n<li data-start=\"3030\" data-end=\"3068\">\n<p data-start=\"3032\" data-end=\"3068\">miten kohinanpoisto v\u00e4hent\u00e4\u00e4 kohinaa<\/p>\n<\/li>\n<li data-start=\"3069\" data-end=\"3112\">\n<p data-start=\"3071\" data-end=\"3112\">miten se samalla pehment\u00e4\u00e4 yksityiskohtia<\/p>\n<\/li>\n<\/ul>\n<hr data-start=\"3114\" data-end=\"3117\" \/>\n<h2 data-start=\"3119\" data-end=\"3173\">3) N\u00e4in arvioit tulokset (riitt\u00e4\u00e4 kameran n\u00e4yt\u00f6lt\u00e4)<\/h2>\n<p data-start=\"3174\" data-end=\"3229\">Katso jokaisesta ISO:sta sama kohta <strong data-start=\"3210\" data-end=\"3228\">100 % zoomilla<\/strong>:<\/p>\n<ol data-start=\"3231\" data-end=\"3247\">\n<li data-start=\"3231\" data-end=\"3247\">\n<p data-start=\"3234\" data-end=\"3247\"><strong data-start=\"3234\" data-end=\"3247\">Varjoissa<\/strong><\/p>\n<\/li>\n<\/ol>\n<ul data-start=\"3248\" data-end=\"3331\">\n<li data-start=\"3248\" data-end=\"3283\">\n<p data-start=\"3250\" data-end=\"3283\">n\u00e4kyyk\u00f6 v\u00e4ril\u00e4ikki\u00e4 (v\u00e4rikohinaa)<\/p>\n<\/li>\n<li data-start=\"3284\" data-end=\"3331\">\n<p data-start=\"3286\" data-end=\"3331\">muuttuuko varjo \u201clikaiseksi\u201d tai laikukkaaksi<\/p>\n<\/li>\n<\/ul>\n<ol start=\"2\" data-start=\"3333\" data-end=\"3360\">\n<li data-start=\"3333\" data-end=\"3360\">\n<p data-start=\"3336\" data-end=\"3360\"><strong data-start=\"3336\" data-end=\"3360\">Tasaisilla pinnoilla<\/strong><\/p>\n<\/li>\n<\/ol>\n<ul data-start=\"3361\" data-end=\"3456\">\n<li data-start=\"3361\" data-end=\"3402\">\n<p data-start=\"3363\" data-end=\"3402\">n\u00e4kyyk\u00f6 rakeisuutta (luminanssikohinaa)<\/p>\n<\/li>\n<li data-start=\"3403\" data-end=\"3456\">\n<p data-start=\"3405\" data-end=\"3456\">pysyyk\u00f6 pinta \u201csiistin\u00e4\u201d vai alkaako kohina h\u00e4irit\u00e4<\/p>\n<\/li>\n<\/ul>\n<ol start=\"3\" data-start=\"3458\" data-end=\"3481\">\n<li data-start=\"3458\" data-end=\"3481\">\n<p data-start=\"3461\" data-end=\"3481\"><strong data-start=\"3461\" data-end=\"3481\">Yksityiskohdissa<\/strong><\/p>\n<\/li>\n<\/ol>\n<ul data-start=\"3482\" data-end=\"3592\">\n<li data-start=\"3482\" data-end=\"3524\">\n<p data-start=\"3484\" data-end=\"3524\">pehmeneek\u00f6 tekstiili\/puunsyy\/hius\/teksti<\/p>\n<\/li>\n<li data-start=\"3525\" data-end=\"3592\">\n<p data-start=\"3527\" data-end=\"3592\">n\u00e4ytt\u00e4\u00e4k\u00f6 kuva \u201cvesiv\u00e4rim\u00e4iselt\u00e4\u201d (tyypillinen NR:n sivuvaikutus)<\/p>\n<\/li>\n<\/ul>\n<h3 data-start=\"3594\" data-end=\"3621\">Kirjaa oma k\u00e4ytt\u00f6rajasi<\/h3>\n<p data-start=\"3622\" data-end=\"3678\">Valitse itsellesi\u00a0 ISO-raja:<\/p>\n<ul data-start=\"3679\" data-end=\"3724\">\n<li data-start=\"3679\" data-end=\"3695\">\n<p data-start=\"3681\" data-end=\"3695\">some \/ puhelin<\/p>\n<\/li>\n<li data-start=\"3696\" data-end=\"3708\">\n<p data-start=\"3698\" data-end=\"3708\">A4-printti<\/p>\n<\/li>\n<li data-start=\"3709\" data-end=\"3724\">\n<p data-start=\"3711\" data-end=\"3724\">tiukka rajaus<\/p>\n<\/li>\n<\/ul>\n<hr data-start=\"3726\" data-end=\"3729\" \/>\n<h2 data-start=\"3731\" data-end=\"3741\">Lopuksi<\/h2>\n<p data-start=\"3742\" data-end=\"4003\">T\u00e4m\u00e4 on JPEG-testiss\u00e4 t\u00e4rkein havainto:<br \/>\nISO ei muuta vain kohinan m\u00e4\u00e4r\u00e4\u00e4, vaan my\u00f6s sit\u00e4, miten kamera k\u00e4sittelee kuvaa (kohinanpoisto ja ter\u00e4v\u00f6itys). Siksi \u201cparas ISO\u201d on k\u00e4yt\u00e4nn\u00f6ss\u00e4 se, jolla saat sinulle sopivan tasapainon kohinan ja yksityiskohtien v\u00e4lill\u00e4.<\/p>\n<\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"<p>Kohinatesti (JPEG) T\u00e4ll\u00e4 testill\u00e4 selvit\u00e4t, milt\u00e4 kamerasi JPEG-j\u00e4lki n\u00e4ytt\u00e4\u00e4 eri ISO-arvoilla. T\u00e4m\u00e4 on k\u00e4yt\u00e4nn\u00f6nl\u00e4heinen testi, koska JPEG-kuvaajana lopputulos syntyy kamerassa: kohina, ter\u00e4v\u00f6itys ja kohinanpoisto vaikuttavat kaikki kuvan ilmeeseen. Tavoite Pid\u00e4 kuvaustilanne ja kuvan kirkkaus mahdollisimman samana, ja katso: milloin kohina alkaa h\u00e4irit\u00e4 milloin kohinanpoisto alkaa sy\u00f6d\u00e4 yksityiskohtia Tarvitset Kamera ja objektiivi Jalusta (suositus) Tasainen valaistus [&hellip;]<\/p>\n","protected":false},"author":2,"featured_media":2487,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[6,1],"tags":[],"class_list":["post-1449","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-tehtavat","category-yleinen"],"_links":{"self":[{"href":"https:\/\/lempea.fi\/vkperus\/wp-json\/wp\/v2\/posts\/1449"}],"collection":[{"href":"https:\/\/lempea.fi\/vkperus\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/lempea.fi\/vkperus\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/lempea.fi\/vkperus\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/lempea.fi\/vkperus\/wp-json\/wp\/v2\/comments?post=1449"}],"version-history":[{"count":7,"href":"https:\/\/lempea.fi\/vkperus\/wp-json\/wp\/v2\/posts\/1449\/revisions"}],"predecessor-version":[{"id":2486,"href":"https:\/\/lempea.fi\/vkperus\/wp-json\/wp\/v2\/posts\/1449\/revisions\/2486"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/lempea.fi\/vkperus\/wp-json\/wp\/v2\/media\/2487"}],"wp:attachment":[{"href":"https:\/\/lempea.fi\/vkperus\/wp-json\/wp\/v2\/media?parent=1449"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/lempea.fi\/vkperus\/wp-json\/wp\/v2\/categories?post=1449"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/lempea.fi\/vkperus\/wp-json\/wp\/v2\/tags?post=1449"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}