{"id":2344,"date":"2013-04-11T09:53:51","date_gmt":"2013-04-11T09:53:51","guid":{"rendered":"https:\/\/www.cg-blog.com\/?p=2344"},"modified":"2013-06-08T13:18:57","modified_gmt":"2013-06-08T13:18:57","slug":"vray-motion-blur","status":"publish","type":"post","link":"https:\/\/www.cg-blog.com\/index.php\/2013\/04\/11\/vray-motion-blur.htm","title":{"rendered":"Motion blur &#8211; It&#8217;s all about balancing"},"content":{"rendered":"<p>Dear friends!<br \/>\nlet&#8217;s start from <a href=\"https:\/\/en.wikipedia.org\/wiki\/Motion_blur\" target=\"_blank\">definition of motion blur<\/a>\u00c2\u00a0I found on wikipedia \ud83d\ude42<\/p>\n<blockquote><p><em><strong>Motion blur<\/strong> is the apparent streaking of rapidly moving objects in a still image or a sequence of images such as a movie or animation. It results when the image being recorded changes during the recording of a single frame, either due to rapid movement or long exposure.<\/em><\/p><\/blockquote>\n<p>I bring this to your attention to highlight &#8211; once more &#8211; how lovely is first understand photography, then simply translate concepts in V-Ray!<\/p>\n<p><strong>Motion blur is\u00c2\u00a0due to rapid movement or long exposure<\/strong>: in few words the subject is moving faster than the shutter speed.<\/p>\n<p><img decoding=\"async\" loading=\"lazy\" class=\"alignnone size-full wp-image-2350\" alt=\"real-blur\" src=\"https:\/\/www.cg-blog.com\/wp-content\/uploads\/2013\/04\/real-blur.jpg\" width=\"600\" height=\"200\" srcset=\"https:\/\/www.cg-blog.com\/wp-content\/uploads\/2013\/04\/real-blur.jpg 600w, https:\/\/www.cg-blog.com\/wp-content\/uploads\/2013\/04\/real-blur-300x100.jpg 300w\" sizes=\"(max-width: 600px) 100vw, 600px\" \/><\/p>\n<p>&nbsp;<\/p>\n<p><strong>MAIN CONDITION<\/strong>: To <strong>get motion blur with V-Ray<\/strong> is getting animated objects. Using <strong>RayFire<\/strong> (a very simple and powerful tool) I already animated this group of nails.<\/p>\n<p>Check the final result in this video:<\/p>\n<p><iframe loading=\"lazy\" src=\"http:\/\/player.vimeo.com\/video\/63806907?title=0&amp;byline=0&amp;portrait=0\" height=\"338\" width=\"600\" allowfullscreen=\"\" frameborder=\"0\"><\/iframe><\/p>\n<p>&nbsp;<\/p>\n<p>As explained in many lessons of our <a href=\"http:\/\/www.learnvray.com\" target=\"_blank\">v-ray course<\/a>, this kind of situation is classified as <strong>medium amount of light<\/strong> that, in our 5SRW standard, means we can use <strong>shutter speed = 50<\/strong> &#8211; Here the draft render at frame 10:<\/p>\n<p><img decoding=\"async\" loading=\"lazy\" class=\"alignnone size-full wp-image-2346\" alt=\"img1-nomb\" src=\"https:\/\/www.cg-blog.com\/wp-content\/uploads\/2013\/04\/img1-nomb.jpg\" width=\"600\" height=\"450\" srcset=\"https:\/\/www.cg-blog.com\/wp-content\/uploads\/2013\/04\/img1-nomb.jpg 600w, https:\/\/www.cg-blog.com\/wp-content\/uploads\/2013\/04\/img1-nomb-300x225.jpg 300w\" sizes=\"(max-width: 600px) 100vw, 600px\" \/><\/p>\n<p><strong>Note<\/strong>: To get motion blur I need to render an intermediate frame, while objects are falling.<\/p>\n<p>&nbsp;<\/p>\n<p>We don&#8217;t need to make meaningless\u00c2\u00a0tests to get this effect! Just ask to yourself:<br \/>\n<strong>Could shutter speed = 50 be an exposure time longer enought to capture falling objects?<\/strong><\/p>\n<p>Every photographer in the world (<strong>V-Ray unaware<\/strong>) would answer: \u00c2\u00a0YESS! Great, so just let&#8217;s enable motion blur in the V-Ray Physical Camera:<\/p>\n<p><img decoding=\"async\" loading=\"lazy\" class=\"alignnone size-full wp-image-2345\" alt=\"motionblur-option\" src=\"https:\/\/www.cg-blog.com\/wp-content\/uploads\/2013\/04\/motionblur-option.gif\" width=\"600\" height=\"200\" \/><\/p>\n<p>&nbsp;<\/p>\n<p>Render again and here the result:<\/p>\n<p><img decoding=\"async\" loading=\"lazy\" class=\"alignnone size-full wp-image-2347\" alt=\"img2-strongblur\" src=\"https:\/\/www.cg-blog.com\/wp-content\/uploads\/2013\/04\/img2-strongblur.jpg\" width=\"600\" height=\"450\" srcset=\"https:\/\/www.cg-blog.com\/wp-content\/uploads\/2013\/04\/img2-strongblur.jpg 600w, https:\/\/www.cg-blog.com\/wp-content\/uploads\/2013\/04\/img2-strongblur-300x225.jpg 300w\" sizes=\"(max-width: 600px) 100vw, 600px\" \/><\/p>\n<p><strong>Of course the photographer was right!<\/strong><\/p>\n<p>The objects are blurred.. too much I say! Motion blur is a great way to communicate dynamism, but it&#8217;s important to get the right quantity of blur in order to create an effective communication. Control the blur controlling the<strong> exposure time<\/strong>.<\/p>\n<p>I can reduce the exposure time increasing shutter speed, but this will reduce the incoming amount of light, so we need to balance with ISO:<\/p>\n<ul>\n<li><span style=\"line-height: 13px;\">reduce exposure time: shutter speed = 50&#8230;. &gt; 300<\/span><\/li>\n<li>increse film sensitivity: ISO = 100&#8230; &gt; 800<\/li>\n<\/ul>\n<p>In this way we keep exposure constant, but objects could appear less blurred:<\/p>\n<p><img decoding=\"async\" alt=\"\" src=\"https:\/\/www.cg-blog.com\/wp-content\/uploads\/2013\/04\/img3-control.jpg\" \/><\/p>\n<p>&nbsp;<\/p>\n<p>Think that motion blur is not fine for sports photographers!!! They need to &#8220;freeze&#8221; the players using very fast shutter speed values. Of course we could just disable &#8220;motion blur&#8221;, but just try to verify if V-Ray is so real as they say \ud83d\ude42<\/p>\n<ul>\n<li>reduce a lot exposure time: shutter speed = 2500<\/li>\n<li>increse film sensitivity: ISO = 4000<\/li>\n<\/ul>\n<p><img decoding=\"async\" loading=\"lazy\" class=\"alignnone size-full wp-image-2349\" alt=\"freeze\" src=\"https:\/\/www.cg-blog.com\/wp-content\/uploads\/2013\/04\/freeze.jpg\" width=\"600\" height=\"450\" srcset=\"https:\/\/www.cg-blog.com\/wp-content\/uploads\/2013\/04\/freeze.jpg 600w, https:\/\/www.cg-blog.com\/wp-content\/uploads\/2013\/04\/freeze-300x225.jpg 300w\" sizes=\"(max-width: 600px) 100vw, 600px\" \/><\/p>\n<p><strong>Magic! V-Ray really works as a real DSLR:\u00c2\u00a0Nails freezed in the air!<\/strong><\/p>\n<p>This is just to demonstrate how V-Ray completely imitate a DSLR behavior.\u00c2\u00a0Note that this image is not exactly as the first one (without motion blur) since <strong>a subtle amount of motion blur is perceptible<\/strong>, making it more realistic than the first image. Of course this means longer render times.<\/p>\n<p>Hope you liked this sneak! \ud83d\ude09<br \/>\nCiro Sannino<\/p>\n<p>&#8211; &#8211; &#8211;<br \/>\n<em>V-Ray Licensed Instructor \/ 5SRW<\/em><br \/>\n<em><\/em><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Motion blur is due to rapid movement or long exposure: let&#8217;s  try to verify if V-Ray is so real as they say.<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"om_disable_all_campaigns":false},"categories":[60],"tags":[],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/www.cg-blog.com\/index.php\/wp-json\/wp\/v2\/posts\/2344"}],"collection":[{"href":"https:\/\/www.cg-blog.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.cg-blog.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.cg-blog.com\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.cg-blog.com\/index.php\/wp-json\/wp\/v2\/comments?post=2344"}],"version-history":[{"count":0,"href":"https:\/\/www.cg-blog.com\/index.php\/wp-json\/wp\/v2\/posts\/2344\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.cg-blog.com\/index.php\/wp-json\/wp\/v2\/media?parent=2344"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.cg-blog.com\/index.php\/wp-json\/wp\/v2\/categories?post=2344"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.cg-blog.com\/index.php\/wp-json\/wp\/v2\/tags?post=2344"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}