Mimicking the blur of classic portrait lenses

[Ken Lee]

I have been fiddling with the CS3 Lens Blur tool.

The physics/math/optics dudes at Adobe have earned their salt, no doubt: In addition to letting you control the overall degree of blur, it lets you specify the number of diaphram blades, and their degree of curvature.

From my experiments, it seems to do a fairly good job of mimicking some of the effects of classic portrait lenses. I imagine that when combined with other Photoshop adjustments, more is possible.

I would like to know if others have experimented with this, in Photoshop or any other tool.

Please: Make no comments about whether such techniques constitute "real" or "authentic" or "genuine" photography. No broadsides, centures, blasts, criticisms, denunciations, or fulminations are necessary. ;)

[Walter Calahan]

Why I'll blast you with my denunciations and fulminations for your questioning what constitutes "real" or "authentic" or "genuine" with full castigations, broadsides and centures on you, your family and your family's family, for suggesting PhotoShop CS3 is any less of a photographic tool then buying a hundred year old brass barreled lens!

Where I come from, Sir, it's whatever floats your boat.

And yes, I have not experimented with any of this stuff yet.

Ha ha ha ha ha

[Photomax]

Ken,

I use this filter all the time. I mainly use it for wedding work. Like most PS filters "less is more"...

The trick is to look at your image at the correct percentages: magnify the image in steps of 25. For example use 50% and not 66% etc. The I usually make a loose selection using the Lasso tool and feather the selection big time, like 88% or so. I then use the Lens Blur tool moderately, like less than 20%. Sometimes I will add just a little Gaussian Blur overall. At the very end I will add a little Smart Sharpen filter before saving the file. It sounds crazy to blur an image and then sharpen it but I find this tightens up the image, especially for portraits etc...

Max

[Jack Flesher]

I've used it pretty extensively and found it works best on it's own layer with some selective masking to let the original image show through. However, while I have had good results, they simply do not fully replicate the special "look" from an older lens or portrait lens like the Cooke.

Cheers,

[Frank Petronio]

I am not using CS3 yet but I was "faking it" 13-14 years ago with primative PS tools ;-) Knowing how a real photo is supposed to look is immensely helpful once you start digging in, thus "real photographers" have the advantage over "digital artists". The key is tapering the blurring realistically, using gradations and careful brush work with layer masks and/or the history brush.

But like PS Noise doesn't quite replicate film grain, PS blurs don't quite match the lens effects. But I can't wait to check out this in CS3.

The classic soft focus lenses -- and modern lenses used with short depth of field technique -- are more than just nice blurring. The edges are rendered differently, there is more of a 3-D look. I can't describe it but I know it when I see it.

FWIW, I think you can fake almost anything in an online 600 -pixel jpg. The test is making full sized prints.

[Gordon Moat]

I thought the tool was okay, though it runs into some obvious (to me) problems. Any time you are working in 2D, and trying to alter what would have been 3D, then there are bound to be issues. Frank sort of mentions this. The basic idea is that the amount of blurring or defocus from a lens will vary with camera to subject (object) distance. So the look of defocus areas from a lens will not appear uniform, though from a software blur tool it will appear more uniform. That could be selectively edited, though it would mean more work.

I have used 3D software in the past that would account for distance when rendering a still image. While not as adjustable as the Blur Tool in PhotoShop, the effect looked more like what you might expect from actually photographing a scene or location.

Ciao!

Gordon Moat
A G Studio (http://www.allgstudio.com)

[Oren Grad]

The basic idea is that the amount of blurring or defocus from a lens will vary with camera to subject (object) distance.

The character of the blur will also vary with the distance of the other things in the picture from the main subject. One can imagine the subject distance being taken into account with some sort of EXIF data from a digital camera (assuming the camera is set to be in focus rather than intentionally set out of focus), but it's hard to imagine where the latter information would come from.

[Gordon Moat]

Interesting idea Oren, though the Distance information on D-SLRs is usually a function of focus plane. So there would not be information on the other objects in the scene.

This reminds me of a college that recently displayed some technology that allowed variation of focal plane after the shot. The mock-up camera was a Contax 645, which I think was putting the results straight to a PhaseOne back. Of course, I don't know how well it worked.

Perhaps if a company revives the Polaroid Sonar autofocus, then records distance information for every object in the scene, then embeds that in the EXIF data, working with a component in the RAW software to get variations of blur relative to camera to object, and even object to object data, all worked into a grid based upon cell site locations, or even Bayer patterning interpolations, allowing one infinite defocus along nearly any object within the scene, all at the touch of a few buttons, or a convenient pull=down menu, perhaps even incorporated into compact digital P&S cameras as the next great marketing feature, then eventually making it into every camera phone on the planet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . or you could simply use a nice lens, manually focus it, select the aperture, and get the results you want in-camera.

Ciao!

Gordon Moat
A G Studio (http://www.allgstudio.com)

[Oren Grad]

Interesting idea Oren, though the Distance information on D-SLRs is usually a function of focus plane. So there would not be information on the other objects in the scene.

Exactly - that's what I meant by "the latter information".


This reminds me of a college that recently displayed some technology that allowed variation of focal plane after the shot. The mock-up camera was a Contax 645, which I think was putting the results straight to a PhaseOne back.

Light Field Photography with a Hand-Held Plenoptic Camera (http://graphics.stanford.edu/papers/lfcamera/)


or you could simply use a nice lens, manually focus it, select the aperture, and get the results you want in-camera.

Life is hard... ;)

[Ken Lee]

Thanks for your excellent responses.

With these additional insights, I have re-visited some earlier threads, and had another look at Jim Galli's wonderful portraits - many of which have been made with vintage lenses.

Now I see the difference. It's definitely... an analog thing !

[scrichton]

I'll have a look I had an amazing tutorial on proper lens blur tool use by the fabled Dr Brown. I learnt the full use of the thing in minutes.

Off to hunt in the CD pile I suppose then.

Steven