blurring the background in Photoshop

[mhahn]

<p>If you're blurring the background in Photoshop, is there any easy way to alter the amount of blur based on how far away objects are from the subject? Do any Photoshop plug-ins have a feature that allows you to do this?</p>

<p>Thanks, Martin</p>

[howard_m]

<p>Onone software has a plugin and I think Topaz might too.</p>

<p>http://www.ononesoftware.com/products/suite/focalpoint/?ind</p>

<p>I have the FocalPoint sw (was a gift) and it does an acceptable job. Whether it's worth the cost is a decision only you can make.</p>

[tom_mann1]

<p>You don't have to go to a 3rd party vendor for this functionality. The "lens blur" filter built into at least the last several versions of PS will accept a depth map. There are many tutorials and explanations of this -- just Google {"lens blur" photoshop "depth map"}.</p>

<p>Focal Point (mentioned above) provides some relatively easy / fast ways to generate an approximate depth map for use within that program, but I never found it to be that much faster than just generating the depth map yourself. OTOH, the OOF blur in Focal Point is much more adjustable than PS's "Lens Blur" filter provides, and IMHO, gives a nicer look to the image (assuming the same depth map is used for both).</p>

<p>For a huge leap up from either of the above, take a look at Richard Rosenman's "DoF Pro" --<br /> http://www.richardrosenman.com/media/software/dof/dof.pdf</p>

<p>HTH,</p>

<p>Tom M</p>

<p> </p>

[peter_cohen]

<p>Topaz has a plug-in called Lens Effects that does blurring, although I find it difficult to use. Then again, I've not really dedicated that much time to learning it.</p>

<p><strong>Tom</strong>: Thanks for the link to DoF Pro, which I had not heard of until your mention. I'm concerned that the last release was in 2009 and it states that the software does not work under 64-bit versions of Photoshop. Has your experience proven otherwise?</p>

[tom_mann1]

<p>Peter - Unfortunately, I've never tried it in a 64 bit environment. Because the rendering can be slow for very large images (ie, where a 64 bit OS/PS comes to the rescue), and because there is essentially no detail in the OOF areas, my trick for handling large images in a 32 bit environment is to down-rez it by fairly large factor, say, 8x in area, perform the blur calculations on the down-rez'ed version, and then up-rez it (with no sharpening) back to the original dimensions. I then mask out portions of the blurred image where I want the original to come through unmodified and at full resolution.</p>

<p>Cheers,</p>

<p>Tom M</p>

[mhahn]

<p>Thank you, everyone. That's a lot of food for thought. I'm hoping to learn to add blur in a way that looks reasonably natural, which doesn't seem to be the case when I blur all of the background and foreground to the same degree. Sounds complicated though. </p>

<p>Actually, I'm not sure how blurring can look "natural," since blurred backgrounds and foregrounds don't really seem to reflect how we see, but you know what I mean.</p>

<p>Martin</p>

[richardsperry]

<p>Martin,</p>

<p>It is possible. But it is complicated. Tom is a much more experienced PhotoShopper than I, so listen to him.</p>

<p>But essentially what you are trying to do is set up a gradient based mask, then apply the blur to that mask.</p>

<p>I know how to do it in PS, it's not very easy. In LR you just brush your blur on what you want blurred, and as thick as you want the blur to be. So I use that now, because it is easy, and the only people who can see it are other PhotoShoppers. Like Tom said, I would not use a plug in; don't need it.</p>

[richardsperry]

<blockquote>

<p>Actually, I'm not sure how blurring can look "natural," since blurred backgrounds and foregrounds don't really seem to reflect how we see, but you know what I mean.</p>

</blockquote>

<p>When we look at something that is 5 feet away, it is in focus. The foreground and background are out of focus naturally.</p>

<p>When we shift our vision to 15 feet, more foreground is out of focus, and more background comes into focus. Naturally.</p>

<p>That is just the way our eyes work, without thinking about it. When we use selective focus, we're are directing the viewer of the photo to what WE want them to focus on. We are overriding their innate natural vision to see our vision of what we want them to focus on.</p>

[jcuknz]

<p>If you want a graduated effect you organise more than one duplicate of the image in the layer stack and blurr them to different degrees and then erase the sharp and partly blurred areas to make it look realistic based on the distance the parts of the background are behind the subject.</p>

[mhahn]

<p>That's sort of conceptually easy to grasp, JC, thanks (although probably not as easy to do).<br>

I wonder if it would be possible to make a filter that would mimic having taken the picture with a higher focal length lens. For instance, if you took the picture with a 28 mm lens, the filter could mimic the depth of field of a 50, 85, 105, etc., mm lens. I guess, in effect, that's what we're talking about doing.</p>

[tom_mann1]

<p>JC, in effect, what you described is what the software mentioned earlier in this thread does automatically, and much more accurately than I could ever do it by hand.</p>

<p>Tom M</p>

[tom_mann1]

<p>Martin H: <em>"...Actually, I'm not sure how blurring can look "natural," since blurred backgrounds and foregrounds don't really seem to reflect how we see, but you know what I mean. ..."</em></p>

<p>The mfgrs of the automated lens blur software packages never claim to be trying to emulate vision. However, many so say that they are trying to emulate the OOF blur of various types of lenses, an effect we have gotten used to through our almost continuous exposure to advertising, TV, movies, the news, and, of course, photographs.</p>

<p>Tom M</p>

[mhahn]

<p>It's curious how something that's not really very natural can nevertheless seem very artificial if you do it badly.</p>

[szrimaging]

<p>You can also use depth maps in photoshop to do a decent job. Never really done one, but try this: <a href="http://photography-on-the.net/forum/showthread.php?t=102294">http://photography-on-the.net/forum/showthread.php?t=102294</a></p>

[mhahn]

<p>Well, I did a search as Tom suggested in his first post, and found a tutorial from Adobe, so maybe I'll try to take a look at that.</p>