{"id":495,"date":"2008-02-06T05:00:58","date_gmt":"2008-02-06T13:00:58","guid":{"rendered":"http:\/\/www.rightreading.com\/blog\/2008\/02\/06\/lens-blur\/"},"modified":"2008-02-05T22:00:19","modified_gmt":"2008-02-06T06:00:19","slug":"lens-blur","status":"publish","type":"post","link":"https:\/\/www.rightreading.com\/blog\/art-and-illustration\/photoshop\/lens-blur\/","title":{"rendered":"Lens blur"},"content":{"rendered":"

While waiting for the Super Tuesday results to come into focus, let’s spend another day on Photoshop before shifting gears to another of our topics. The other day I talked about faking a tilt-shift effect<\/a>, which basically involves blurring a gradient mask. Because I was blogging from home, where I don’t have a recent version of Photoshop, I used a Gaussian blur instead of a lens blur.<\/p>\n

So what’s the difference? In theory, there’s a fundamental difference, which can clearly be seen in the following chart based on a Russell Brown presentation reported on Computer Darkroom<\/a>.<\/p>\n

\"lens<\/p>\n

You can see that Gaussian blur, in the middle column, erodes edges and grays white areas, while lens blur, in the right column, applies a geometric (somewhat hexagonal) effect similar to that of a camera lens without dulling highlights.<\/p>\n

In the real world, however, the results may not be as noticeable. Here is an image with a Gaussian blur (top) and a lens blur (bottom). Because they use different metrics, it was difficult to get the amount of blur identical; nonetheless, the results look fairly similar — maybe the lens blur is a little crisper. That could partially be because I didn’t blur it quite as much, but I think its range of tones is also a little different.<\/p>\n

\"gaussian<\/p>\n

I’m getting to like the lens blur effect. It feels like it gives you a little better control. Right now I’m working on a book about the Chinese artist Zhan Wang. For this book I’ve applied some selective lens blurring to some of the images. Following is an example — original photo on top and modified photo beneath. For this image I applied a quick mask to select the figures and foreground rocks, then lens blurred the rest. (Of course I also did my usual adjustments<\/a>.) Do you like this effect?<\/p>\n

\"original<\/p>\n","protected":false},"excerpt":{"rendered":"

While waiting for the Super Tuesday results to come into focus, let’s spend another day on Photoshop before shifting gears to another of our topics. The other day…<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"ngg_post_thumbnail":0},"categories":[72],"tags":[],"_links":{"self":[{"href":"https:\/\/www.rightreading.com\/blog\/wp-json\/wp\/v2\/posts\/495"}],"collection":[{"href":"https:\/\/www.rightreading.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.rightreading.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.rightreading.com\/blog\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.rightreading.com\/blog\/wp-json\/wp\/v2\/comments?post=495"}],"version-history":[{"count":0,"href":"https:\/\/www.rightreading.com\/blog\/wp-json\/wp\/v2\/posts\/495\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.rightreading.com\/blog\/wp-json\/wp\/v2\/media?parent=495"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.rightreading.com\/blog\/wp-json\/wp\/v2\/categories?post=495"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.rightreading.com\/blog\/wp-json\/wp\/v2\/tags?post=495"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}