{"id":260,"date":"2019-04-08T15:28:25","date_gmt":"2019-04-08T13:28:25","guid":{"rendered":"https:\/\/koustrup.com\/?page_id=260"},"modified":"2021-10-10T16:08:22","modified_gmt":"2021-10-10T14:08:22","slug":"blaenden","status":"publish","type":"page","link":"https:\/\/foto-video.dk\/?page_id=260","title":{"rendered":"2.2: Bl\u00e6nden"},"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; width: 35%; border: 0px; padding: 2px;\"><img decoding=\"async\" class=\"alignleft size-medium wp-image-2775\" src=\"https:\/\/foto-video.dk\/wp-content\/uploads\/2021\/10\/Blaenden-2-300x199.png\" alt=\"\" width=\"300\" height=\"199\" srcset=\"https:\/\/foto-video.dk\/wp-content\/uploads\/2021\/10\/Blaenden-2-300x199.png 300w, https:\/\/foto-video.dk\/wp-content\/uploads\/2021\/10\/Blaenden-2.png 423w\" sizes=\"(max-width: 300px) 100vw, 300px\" \/><\/td>\n<td style=\"text-align: left; vertical-align: top; border: 0px; padding: 2px;\" colspan=\"2\">\n<ul>\n<li><b>Bl\u00e6nden<\/b> er en <b>plade<\/b> med et <b>hul<\/b> (fast bl\u00e6nde) normalt mindre end linsernes diameter, og som sidder inde i objektivet \u2013 normalt efter den sidste eller n\u00e6stsidste linse.<\/li>\n<li>Bl\u00e6nden kan udformes som en r\u00e6kke lameller, der kan variere hullets st\u00f8rrelse.<\/li>\n<li>Jo <b>st\u00f8rre bl\u00e6nde \u00e5bning<\/b> \u2013 jo <b>mere lys <\/b>vil n\u00e5 frem til sensoren per tidsenhed.<\/li>\n<\/ul>\n<\/td>\n<\/tr>\n<tr>\n<td style=\"text-align: left; vertical-align: top; width: 65%; border: 0px; padding: 2px;\" colspan=\"2\">\nGrunden til man inds\u00e6tter denne plade i lysgangen er, at hvis den ikke var der, vil man kun kunne fokusere punkter der ligger i n\u00f8jagtig samme afstand fra f\u00f8rste linse \u2013 i v\u00e6rste fald kun et enkelt punkt (nogenlunde som hvis vi kniber \u00f8jnene sammen for at fokusere bedre).<br \/>\nDesuden vil bl\u00e6nden i sagens natur ogs\u00e5 regulere m\u00e6ngden af lys der kommer ind igennem objektivet (per tidsenhed).<\/td>\n<td style=\"text-align: left; vertical-align: top; width: 35%; border: 0px; padding: 2px;\"><img decoding=\"async\" class=\"size-medium wp-image-2776 alignright\" src=\"https:\/\/foto-video.dk\/wp-content\/uploads\/2021\/10\/Blaenden-3-300x218.jpg\" alt=\"\" width=\"300\" height=\"218\" srcset=\"https:\/\/foto-video.dk\/wp-content\/uploads\/2021\/10\/Blaenden-3-300x218.jpg 300w, https:\/\/foto-video.dk\/wp-content\/uploads\/2021\/10\/Blaenden-3.jpg 491w\" 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\">Objektivets bl\u00e6ndetal (<b>f<\/b>) fort\u00e6ller hvor meget lys objektivet lader passere til sensoren.<br \/>\nDet er en funktion af objektivets br\u00e6ndvidde og diameteren p\u00e5 bl\u00e6nde\u00e5bningen.<\/p>\n<table style=\"width: 75%; float: center; border: 2px solid black; padding: 5px; margin-right: auto; margin-left: auto;\">\n<tbody>\n<tr>\n<td style=\"text-align: center; vertical-align: middle; border: 0px; padding: 2px;\">\n<h3 style=\"text-align: center;\"><b>F<\/b> = Br\u00e6ndvidde (mm) \/ bl\u00e6nde\u00e5bningens diameter(mm)<\/h3>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>Bl\u00e6nden er dimensionsl\u00f8s og skrives som <b><i>f<\/i><\/b>tal, F\/tal, eller 1:tal.<br \/>\nDet <b>mindste bl\u00e6ndetal<\/b>, er s\u00e5ledes den <b>st\u00f8rste \u00e5bning <\/b>!!! Man kan ogs\u00e5 sige at jo h\u00f8jere bl\u00e6ndetal, jo mere lys holdes tilbage.<\/p>\n<p>Hvert trin i bl\u00e6nder\u00e6kken (<b><i>f<\/i><\/b>1,4 -&gt; <b><i>f<\/i><\/b>2) halverer m\u00e6ngden af lys der kommer frem til sensoren \u2013 en fordobling af bl\u00e6ndetallet (<b><i>f<\/i><\/b>1,4 -&gt; <b><i>f<\/i><\/b>2,8) vil s\u00e5ledes kun lade 25% af lyset komme igennem.<\/p>\n<p>Nedenst\u00e5ende bl\u00e6nder\u00e6kke er i hele stop. Bl\u00e6nder\u00e6kken starter med <em><strong>f<\/strong><\/em>1.0, n\u00e6ste stop (ned) findes ved at gange tallet med kvadratroden af 2.<\/p>\n<p><strong>Bl\u00e6nden<\/strong> regulerer ogs\u00e5 <strong>dybdeskarpheden<\/strong> i billedet, sammen med br\u00e6ndvidde, afstand til fokuspunkt og sensorens pixelareal (ref.: <a href=\"https:\/\/foto-video.dk\/?page_id=397\">Dybdeskarphed<\/a>).<\/td>\n<\/tr>\n<tr>\n<td style=\"text-align: center; vertical-align: top; border: 0px; padding: 2px;\" colspan=\"3\"><img decoding=\"async\" class=\"aligncenter wp-image-2780 size-full\" src=\"https:\/\/foto-video.dk\/wp-content\/uploads\/2021\/10\/Blaenden-5.png\" alt=\"\" width=\"1128\" height=\"558\" srcset=\"https:\/\/foto-video.dk\/wp-content\/uploads\/2021\/10\/Blaenden-5.png 1128w, https:\/\/foto-video.dk\/wp-content\/uploads\/2021\/10\/Blaenden-5-300x148.png 300w, https:\/\/foto-video.dk\/wp-content\/uploads\/2021\/10\/Blaenden-5-1024x507.png 1024w, https:\/\/foto-video.dk\/wp-content\/uploads\/2021\/10\/Blaenden-5-768x380.png 768w\" sizes=\"(max-width: 1128px) 100vw, 1128px\" \/><\/td>\n<\/tr>\n<tr>\n<td style=\"text-align: left; vertical-align: top; border: 0px; padding: 2px;\" colspan=\"3\"><strong>Sm\u00e5 bl\u00e6nde\u00e5bninger<\/strong> vil give en st\u00f8rre dybdeskarphed. Desv\u00e6rre er der et lille \u2018men\u2019 ved <strong>sm\u00e5 bl\u00e6nde\u00e5bninger<\/strong> \u2013<strong> lys diffraktion<\/strong> (Light Diffraction).<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<table style=\"width: 99%; float: center; border: 0px; padding: 5px; margin-right: auto; margin-left: auto;\">\n<tbody>\n<tr>\n<td style=\"vertical-align: top; width: 30%; border: 0px; padding: 2px; text-align: center;\">\n<p><div id=\"attachment_2782\" style=\"width: 260px\" class=\"wp-caption alignleft\"><img decoding=\"async\" aria-describedby=\"caption-attachment-2782\" class=\"wp-image-2782\" src=\"https:\/\/foto-video.dk\/wp-content\/uploads\/2021\/10\/Blaenden-6.png\" alt=\"\" width=\"250\" height=\"195\" \/><p id=\"caption-attachment-2782\" class=\"wp-caption-text\"><strong>Lysdiffraktion<\/strong><\/p><\/div><\/td>\n<td style=\"text-align: left; vertical-align: top; border: 0px; padding: 2px;\">Det er et optisk f\u00e6nomen, hvor der dannes lysb\u00f8lger omkring kanten af bl\u00e6nden. Disse vil danne et <strong>diffraktionsm\u00f8nster p\u00e5 sensoren<\/strong>. Dette m\u00f8nster vil g\u00f8re billedet uskarpt eller sl\u00f8ret \u2013 jo mindre pixelst\u00f8rrelse jo mere udtalt vil det v\u00e6re.<\/p>\n<p><strong>Diffraktionsm\u00f8nsteret<\/strong> kaldes ogs\u00e5 en\u00a0<strong><span style=\"background-color: transparent;\">Airy Dis<\/span><span style=\"background-color: transparent;\">c<\/span><\/strong><\/td>\n<td style=\"text-align: center; vertical-align: top; width: 25%; border: 0px; padding: 2px;\">\n<p><div id=\"attachment_2783\" style=\"width: 160px\" class=\"wp-caption aligncenter\"><img decoding=\"async\" aria-describedby=\"caption-attachment-2783\" class=\"wp-image-2783 size-thumbnail\" src=\"https:\/\/foto-video.dk\/wp-content\/uploads\/2021\/10\/Blaenden-7-150x150.png\" alt=\"\" width=\"150\" height=\"150\" srcset=\"https:\/\/foto-video.dk\/wp-content\/uploads\/2021\/10\/Blaenden-7-150x150.png 150w, https:\/\/foto-video.dk\/wp-content\/uploads\/2021\/10\/Blaenden-7.png 221w\" sizes=\"(max-width: 150px) 100vw, 150px\" \/><p id=\"caption-attachment-2783\" class=\"wp-caption-text\"><strong>Airy Disc<\/strong><\/p><\/div><\/td>\n<\/tr>\n<tr>\n<td style=\"text-align: left; vertical-align: top; border: 0px; padding: 2px;\" colspan=\"3\">Den <strong>st\u00f8rste praktiske bl\u00e6nde<\/strong>, hvor dette <strong>ikke kan ses<\/strong> er omkring <em><strong>f<\/strong><\/em>8 \u2013&gt; <em><strong>f<\/strong><\/em>11<\/td>\n<\/tr>\n<tr>\n<td style=\"vertical-align: top; border: 0px; padding: 2px; text-align: center;\" colspan=\"3\"><img decoding=\"async\" class=\"aligncenter size-full wp-image-2784\" src=\"https:\/\/foto-video.dk\/wp-content\/uploads\/2021\/10\/Blaenden-8.png\" alt=\"\" width=\"717\" height=\"322\" srcset=\"https:\/\/foto-video.dk\/wp-content\/uploads\/2021\/10\/Blaenden-8.png 717w, https:\/\/foto-video.dk\/wp-content\/uploads\/2021\/10\/Blaenden-8-300x135.png 300w\" sizes=\"(max-width: 717px) 100vw, 717px\" \/><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<hr \/>\n<p style=\"text-align: left;\"><strong>Underbyggende artikler<\/strong>:<\/p>\n<ul>\n<li><a href=\"https:\/\/foto-video.dk\/?page_id=1600\"><strong>Transmission &#8211; T-v\u00e6rdi<\/strong><\/a><\/li>\n<li><a href=\"https:\/\/foto-video.dk\/?page_id=1574\"><strong>Bl\u00e6nde\u00e5bningens areal og lysm\u00e6ngden<\/strong><\/a><\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"<p>Bl\u00e6nden er en plade med et hul (fast bl\u00e6nde) normalt mindre end linsernes diameter, og som sidder inde i objektivet \u2013 normalt efter den sidste eller n\u00e6stsidste linse. Bl\u00e6nden kan udformes som en r\u00e6kke lameller, der kan variere hullets st\u00f8rrelse. Jo st\u00f8rre bl\u00e6nde \u00e5bning \u2013 jo mere lys vil n\u00e5 frem til sensoren per tidsenhed. [&hellip;]<\/p>\n","protected":false},"author":2,"featured_media":0,"parent":112,"menu_order":20,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-260","page","type-page","status-publish","hentry","post"],"_links":{"self":[{"href":"https:\/\/foto-video.dk\/index.php?rest_route=\/wp\/v2\/pages\/260","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=260"}],"version-history":[{"count":14,"href":"https:\/\/foto-video.dk\/index.php?rest_route=\/wp\/v2\/pages\/260\/revisions"}],"predecessor-version":[{"id":2791,"href":"https:\/\/foto-video.dk\/index.php?rest_route=\/wp\/v2\/pages\/260\/revisions\/2791"}],"up":[{"embeddable":true,"href":"https:\/\/foto-video.dk\/index.php?rest_route=\/wp\/v2\/pages\/112"}],"wp:attachment":[{"href":"https:\/\/foto-video.dk\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=260"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}