{"id":227,"date":"2019-04-08T13:59:18","date_gmt":"2019-04-08T11:59:18","guid":{"rendered":"https:\/\/koustrup.com\/?page_id=227"},"modified":"2021-10-09T17:22:38","modified_gmt":"2021-10-09T15:22:38","slug":"optisk-forvraengning-optical-distortion","status":"publish","type":"page","link":"https:\/\/foto-video.dk\/?page_id=227","title":{"rendered":"2.1.6: Optisk forvr\u00e6ngning (optical distortion)"},"content":{"rendered":"<nav aria-label=\"breadcrumbs\">\n            <div class=\"breadcrumb-container theme1\">\n                <ol>\n                    <li><a title=\"Du er her\" href=\"#\"><span>Du er her<\/span><\/a><span class=\"separator\">&gt;&gt;<\/span><\/li>\n                    <\/ol>\n            <\/div>\n        <\/nav>    <script type=\"application\/ld+json\">\n        {\n            \"@context\": \"http:\/\/schema.org\",\n            \"@type\": \"BreadcrumbList\",\n            \"itemListElement\": [\n                 {\n                            \"@type\": \"ListItem\",\n                            \"position\": 1,\n                            \"item\": {\n                                \"@id\": \"#\",\n                                \"name\": \"Du er her\"\n                            }\n                        }\n                                                    ]\n        }\n    <\/script>\n   \n    <script>\n            <\/script>\n\n<hr \/>\n<p><!-- Hoved Tabel --><\/p>\n<table style=\"width: 99%; float: center; border: 0px; padding: 5px; margin-right: auto; margin-left: auto;\">\n<tbody>\n<tr>\n<td style=\"text-align: left; vertical-align: top; border: 0px; padding: 2px; width: 102%;\" colspan=\"3\"><strong>Optisk forvr\u00e6ngning<\/strong> er, n\u00e5r rette linjer bliver krummet af objektivet (linsen) eller n\u00e5r de fotograferes igennem et transparent emne (fx vinglas).<\/td>\n<\/tr>\n<tr>\n<td style=\"text-align: left; vertical-align: top; width: 35%; border: 0px; padding: 5px;\"><img decoding=\"async\" class=\"alignnone size-full wp-image-2738\" src=\"https:\/\/foto-video.dk\/wp-content\/uploads\/2021\/10\/optisk-forvraengning-1.jpg\" alt=\"\" width=\"419\" height=\"278\" srcset=\"https:\/\/foto-video.dk\/wp-content\/uploads\/2021\/10\/optisk-forvraengning-1.jpg 419w, https:\/\/foto-video.dk\/wp-content\/uploads\/2021\/10\/optisk-forvraengning-1-300x199.jpg 300w\" sizes=\"(max-width: 419px) 100vw, 419px\" \/><\/td>\n<td style=\"text-align: left; vertical-align: top; width: 67%; border: 0px; padding: 2px;\" colspan=\"2\">Man taler om tre former for optisk forvr\u00e6ngning &#8211;<\/p>\n<ul>\n<li><strong><span style=\"background-color: transparent;\">T\u00f8nde<\/span><\/strong><span style=\"background-color: transparent;\"><strong>forvr\u00e6ngning<\/strong> (barrel distortion)<\/span><\/li>\n<li><strong>N\u00e5lepude<\/strong> (Pincushion distortion)<\/li>\n<li><strong>Bump<\/strong> (Mustache distortion)<\/li>\n<\/ul>\n<\/td>\n<\/tr>\n<tr>\n<td style=\"text-align: left; vertical-align: middle; border: 0px; padding: 2px;\" colspan=\"3\">\n<hr \/>\n<\/td>\n<\/tr>\n<tr>\n<td style=\"text-align: left; vertical-align: top; width: 65%; border: 0px; padding: 2px;\" colspan=\"2\">Ved <strong>t\u00f8ndeforvr\u00e6ngning<\/strong> bliver forst\u00f8rrelsesgraden mindre efterh\u00e5nden, som man bev\u00e6ger sig bort fra det optiske centrum.<br \/>\nEffekten er som billedet er afsat p\u00e5 en kugle eller t\u00f8nde.<br \/>\nFiske\u00f8je objektiver bruger dette til at afbilde det krumme motiv p\u00e5 en \u2018flad\u2019 sensor, og alle fiske\u00f8je motiver har denne forvr\u00e6ngning i mere eller mindre grad (afh\u00e6ngig af br\u00e6ndvidde).<br \/>\nI zoom objektiver vil denne forvr\u00e6ngning starte med at optr\u00e6de i den midterste del af zoom br\u00e6ndvidden, og er v\u00e6rst i den mindste br\u00e6ndvidde.<br \/>\nVidvinkel objektiver har denne forvr\u00e6ngning i mere eller mindre grad (afh\u00e6ngig af br\u00e6ndvidde).<\/td>\n<td style=\"text-align: left; vertical-align: top; width: 35%; border: 0px; padding: 2px;\"><img decoding=\"async\" class=\"alignright wp-image-2739 size-medium\" src=\"https:\/\/foto-video.dk\/wp-content\/uploads\/2021\/10\/optisk-forvraengning-2-300x300.png\" alt=\"\" width=\"300\" height=\"300\" srcset=\"https:\/\/foto-video.dk\/wp-content\/uploads\/2021\/10\/optisk-forvraengning-2-300x300.png 300w, https:\/\/foto-video.dk\/wp-content\/uploads\/2021\/10\/optisk-forvraengning-2-150x150.png 150w, https:\/\/foto-video.dk\/wp-content\/uploads\/2021\/10\/optisk-forvraengning-2.png 318w\" sizes=\"(max-width: 300px) 100vw, 300px\" \/><\/td>\n<\/tr>\n<tr>\n<td style=\"text-align: left; vertical-align: top; border: 0px; padding: 2px;\" colspan=\"3\">\u200b<\/p>\n<table style=\"width: 99%; float: center; border: 0; padding: 5px; margin-right: auto; margin-left: auto;\">\n<tbody>\n<tr>\n<td style=\"width: 20%; float: center; vertical-align: top; border: 0; padding: 5px;\">\n<p><div id=\"attachment_2741\" style=\"width: 210px\" class=\"wp-caption alignleft\"><img decoding=\"async\" aria-describedby=\"caption-attachment-2741\" class=\"wp-image-2741 size-medium\" src=\"https:\/\/foto-video.dk\/wp-content\/uploads\/2021\/10\/2019_D810_00676-200x300.jpg\" alt=\"\" width=\"200\" height=\"300\" srcset=\"https:\/\/foto-video.dk\/wp-content\/uploads\/2021\/10\/2019_D810_00676-200x300.jpg 200w, https:\/\/foto-video.dk\/wp-content\/uploads\/2021\/10\/2019_D810_00676-683x1024.jpg 683w, https:\/\/foto-video.dk\/wp-content\/uploads\/2021\/10\/2019_D810_00676-768x1151.jpg 768w, https:\/\/foto-video.dk\/wp-content\/uploads\/2021\/10\/2019_D810_00676-1025x1536.jpg 1025w, https:\/\/foto-video.dk\/wp-content\/uploads\/2021\/10\/2019_D810_00676.jpg 1281w\" sizes=\"(max-width: 200px) 100vw, 200px\" \/><p id=\"caption-attachment-2741\" class=\"wp-caption-text\">Zoom 24 &#8211; 70 mm \/ f2.8 br\u00e6ndvidde 24 mm<\/p><\/div><\/td>\n<td style=\"float: center; vertical-align: top; border: 0; padding: 5px;\">Billedet til venstre er taget med en br\u00e6ndvidde p\u00e5 24 mm (fuldformat) og billedet til h\u00f8jre er taget med en br\u00e6ndvidde p\u00e5 70 mm &#8211; af samme objektiv.<\/p>\n<p>Man kan tydeligt se t\u00f8ndeforvr\u00e6ngningen p\u00e5 venstre billede, hvor ansigtet er mere &#8216;rundt&#8217; og trukket ud. Desuden bliver n\u00e6sen mere markant &#8211; det ser ud som om hun har en k\u00e6mpestor n\u00e6se.<\/p>\n<p>L\u00e6g ogs\u00e5 m\u00e6rke til hvordan h\u00e5ret (parykken) er trukket ud mod siderne.<\/td>\n<td style=\"width: 20%; float: center; vertical-align: top; border: 0; padding: 5px;\">\n<p><div id=\"attachment_2742\" style=\"width: 210px\" class=\"wp-caption alignright\"><img decoding=\"async\" aria-describedby=\"caption-attachment-2742\" class=\"wp-image-2742 size-medium\" src=\"https:\/\/foto-video.dk\/wp-content\/uploads\/2021\/10\/2019_D810_00677-200x300.jpg\" alt=\"\" width=\"200\" height=\"300\" srcset=\"https:\/\/foto-video.dk\/wp-content\/uploads\/2021\/10\/2019_D810_00677-200x300.jpg 200w, https:\/\/foto-video.dk\/wp-content\/uploads\/2021\/10\/2019_D810_00677-683x1024.jpg 683w, https:\/\/foto-video.dk\/wp-content\/uploads\/2021\/10\/2019_D810_00677-768x1151.jpg 768w, https:\/\/foto-video.dk\/wp-content\/uploads\/2021\/10\/2019_D810_00677-1025x1536.jpg 1025w, https:\/\/foto-video.dk\/wp-content\/uploads\/2021\/10\/2019_D810_00677.jpg 1281w\" sizes=\"(max-width: 200px) 100vw, 200px\" \/><p id=\"caption-attachment-2742\" class=\"wp-caption-text\">Zoom 24 &#8211; 70 mm \/ f2.8 br\u00e6ndvidde 70 mm<\/p><\/div><\/td>\n<\/tr>\n<tr>\n<td style=\"text-align: left; vertical-align: middle; border: 0px; padding: 2px;\" colspan=\"3\">Specielt ved portr\u00e6tter er det vigtigt at undg\u00e5 t\u00f8ndeforvr\u00e6ngning, s\u00e5 derfor b\u00f8r man altid bruge en br\u00e6ndvidde p\u00e5 mindst 50 mm ved portr\u00e6tter; en br\u00e6ndvidde p\u00e5 70 mm og op er endnu bedre.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/td>\n<\/tr>\n<tr>\n<td style=\"text-align: left; vertical-align: middle; border: 0px; padding: 2px;\" colspan=\"3\">\n<hr \/>\n<\/td>\n<\/tr>\n<tr>\n<td style=\"text-align: left; vertical-align: top; width: 35%; border: 0px; padding: 2px;\"><img decoding=\"async\" class=\"alignleft size-full wp-image-2746\" src=\"https:\/\/foto-video.dk\/wp-content\/uploads\/2021\/10\/optisk-forvraengning-3.jpg\" alt=\"\" width=\"163\" height=\"165\" \/><\/td>\n<td style=\"text-align: left; vertical-align: top; width: 65%; border: 0px; padding: 2px;\" colspan=\"2\">Ved <strong>n\u00e5lepudeforvr\u00e6ngning<\/strong> bliver forst\u00f8rrelsen st\u00f8rre jo l\u00e6ngere v\u00e6k vi bev\u00e6ger os fra de optiske akser.<br \/>\nEffekten er at linjer som ikke g\u00e5r igennem billede center krummer indad \u2013 det ser ud som der er en fordybning i billedet (pincushion).<\/td>\n<\/tr>\n<tr>\n<td style=\"text-align: center; vertical-align: middle; border: 0px; padding: 2px;\" colspan=\"3\">\n<hr \/>\n<\/td>\n<\/tr>\n<tr>\n<td style=\"text-align: left; vertical-align: top; width: 65%; border: 0px; padding: 2px;\" colspan=\"2\"><strong>Bump forvr\u00e6ngning<\/strong> er en blanding af de to foreg\u00e5ende. Den er ikke s\u00e5 almindelig. Omkring billede center er der tale om en t\u00f8nde forvr\u00e6ngning som langsom mod kanten \u00e6ndrer sig til en n\u00e5lepudeforvr\u00e6ngning. Resultatet er, at det ser ud til der en bule i billedet samtidigt med horisontale linjer i toppen krummer s\u00e5 de ligner et oversk\u00e6g .<\/td>\n<td style=\"text-align: left; vertical-align: top; width: 35%; border: 0px; padding: 2px;\"><img decoding=\"async\" class=\"alignright size-full wp-image-2748\" src=\"https:\/\/foto-video.dk\/wp-content\/uploads\/2021\/10\/optisk-forvraenging-4.jpg\" alt=\"\" width=\"162\" height=\"165\" \/><\/td>\n<\/tr>\n<tr>\n<td style=\"text-align: center; vertical-align: middle; border: 0px; padding: 2px;\" colspan=\"3\">\n<hr \/>\n<\/td>\n<\/tr>\n<tr>\n<td style=\"text-align: left; vertical-align: top; border: 0px; padding: 2px;\" colspan=\"3\">Optisk forvr\u00e6ngning (eller perspektiv forvr\u00e6ngning) optr\u00e6der specielt i zoom objektiver og specielt i objektiver med et stort sp\u00e6nd i br\u00e6ndvidden (super zoom).<br \/>\nT\u00f8ndeforvr\u00e6ngning optr\u00e6der is\u00e6r i fiske\u00f8je- og vidvinkel objektiver, men kan ogs\u00e5 ses vidvinkel br\u00e6ndvidden i zoom objektiver.<br \/>\nN\u00e5lepudeforvr\u00e6ngning ses ofte i \u00e6ldre tele objektiver.<br \/>\nBump forvr\u00e6ngning ses ofte i vidvinkel enden af super zoom objektiver (fx Nikon 18 \u2013 200 mm)Mange fotoprogrammer indeholder en mulighed for at kompensere for objektivets optiske forvr\u00e6ngning (fx Lightroom, DXO optics, Capture One).<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<hr \/>\n<p style=\"text-align: right;\"><a href=\"https:\/\/foto-video.dk\/?page_id=140\"><strong>Tilbage til objektivet&gt;<\/strong><\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Optisk forvr\u00e6ngning er, n\u00e5r rette linjer bliver krummet af objektivet (linsen) eller n\u00e5r de fotograferes igennem et transparent emne (fx vinglas). Man taler om tre former for optisk forvr\u00e6ngning &#8211; T\u00f8ndeforvr\u00e6ngning (barrel distortion) N\u00e5lepude (Pincushion distortion) Bump (Mustache distortion) Ved t\u00f8ndeforvr\u00e6ngning bliver forst\u00f8rrelsesgraden mindre efterh\u00e5nden, som man bev\u00e6ger sig bort fra det optiske centrum. Effekten [&hellip;]<\/p>\n","protected":false},"author":2,"featured_media":0,"parent":140,"menu_order":35,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-227","page","type-page","status-publish","hentry","post"],"_links":{"self":[{"href":"https:\/\/foto-video.dk\/index.php?rest_route=\/wp\/v2\/pages\/227","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/foto-video.dk\/index.php?rest_route=\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/foto-video.dk\/index.php?rest_route=\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/foto-video.dk\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/foto-video.dk\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=227"}],"version-history":[{"count":12,"href":"https:\/\/foto-video.dk\/index.php?rest_route=\/wp\/v2\/pages\/227\/revisions"}],"predecessor-version":[{"id":2752,"href":"https:\/\/foto-video.dk\/index.php?rest_route=\/wp\/v2\/pages\/227\/revisions\/2752"}],"up":[{"embeddable":true,"href":"https:\/\/foto-video.dk\/index.php?rest_route=\/wp\/v2\/pages\/140"}],"wp:attachment":[{"href":"https:\/\/foto-video.dk\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=227"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}