Lens Blur Filter

[gmitchel]

I really like the Lens Blur filter in PS CS. It does a much better job of blurring backgrounds than a simple Gaussian Blur.

I attached two images to this message. The first is a simple JPG directly from the RAW file. It is an image of a white iris from Leu Botanical Garden in Orlando, FL. I used a Canon 10D camera, a Kirk Dual Macro Flash Bracket, 2 Canon 550EX flashes, and a Canon 180mm "L" macro lens.

As you can see, I pretty well nailed the exposure. I used f/32 for maximum DOF because I wanted to get the iris sharp from petal tip to petal tip. Unfortunately, f/32 also allows a lot of background detail.

I cropped the image to 4:5 aspect ratio. Duplicated the background layer. Converted the image to 8-bits, since the Lens Blur filter is 8-bits only.

For the reduced DOF, I started with a mask of the white flower. I used the red channel to make the mask. It took all of two minutes to generate the mask, save it as an alpha channel, and clean it up with the brush tool. Then I inverted the mask and applied a 1 pixel Gaussian Blur to soften the edges of the mask.

The settings for the Lens Blur filter were:
(1) use the alpha channel as the depth map source
(2) 240 as the Blur Focal Distance
(3) "Invert" check box checked
(4) Hexagon iris shape with 75 for radius and 0 for curvature and rotation
(5) Brightness 20 and threshold 255 for specular highlights
(6) Noise 5, Gaussian distribution
(7) "Monochromatic" checkbox not checked.

The second image shows the final result. You can also see it temporarily on my home page (http://www.thelightsrightstudio.com). I added my new gallery print edge effect to the image. I'm in the process of renovating my galleries, and one of the changes is to use this new gallery print look to my Web images.

The background is much less distracting. I get the benefit of maiximizing DOF for the white iris while narrowing the DOF behind the iris in a way that looks very similar to the bokah I expect with my 180mm "L" macro lens.

Comments are welcome!

Cheers,

Mitch

[Leah]

I've been playing around with the Lens Blur filter too. Do you have any examples with two original shots, one shot with a wide aperture for narrow DOF and one shot with a narrow aperture and the DOF recreated with Lens Blur? That's what I've been meaning to set up to experiment and see how close I can get to lens bokeh, but there never seem to be enough hours in the day... even the lens blur filter never looks quite right to me, but without seeing properly what the in-camera effect looks like it's hard to be sure.

Your iris shot is certainly effective and I agree the Lens Blur is much better than the old Gaussian Blur. And I love your border/frame, which is very effective.

[gmitchel]

Thanks, Leah.

I learned the gallery frame effect from Scott Kelby.

I wrote a tutorial today on the Lens Blur filter. It explains how to reduce DOF with it.

http://www.thelightsright.com/Digita...pthOfField.pdf

Cheers,

Mitch

[Ed_L]

Hi Mitch,

That is an *excellent* job on reducing DOF. It looks *very* right to me. Although I'm still using 7.0, I think it would be a very welcomed addition to put in our tutorial section. If you put it here, it would always be available, and easy for others on the site to find in the future. Maybe I'll upgrade when the next version of Photoshop comes out. Then I'll be able to try to match your excellent results.

Ed