Tuesday, May 11, 2010
The Art Of Selective Focus
Use creative focus techniques to direct attention and add mystery and mood to your images
Nikon D3, 45mm tilt- shift, 1/320 at ƒ/2.8, ISO 200
Sometimes, after a shoot, I wish I had used creative focus techniques. There are many post processing options to create this effect in Photoshop and third-party plug-ins that simplify the process.
One of the easiest ways to add blur to an image is using layer masks and the Brush tool in Photoshop CS4. Begin by opening your image. Next, duplicate the background layer (Command+J for Mac, Control+J for Windows). With the duplicate layer active, choose Filter > Blur > Lens Blur. For high-resolution files, I choose a Radius setting of around 40. Next, add a mask to this layer and fill it with black. This will hide the Lens Blur effect. Choose the Brush tool using a soft-edged brush and lower the brush opacity to 30%. Make sure your foreground color is white, and begin to brush your blur back into the image where you want it. Having the brush opacity set to 30% allows you to feather in the blur. Don’t brush over any areas you want sharp.
I normally use another Photoshop technique, more advanced, but with more realistic selective-focus effects. Start by opening your image and then open the Channels palette (the tab right beside the Layers palette). Create a new channel by using the Create New Channel icon at the bottom right side of the Channels palette. With the new channel active, choose the Gradient tool and make sure the gradient is set to “Black, White” (use the gradient picker to choose this, the shaded rectangular bar in the upper-left corner of this window). Put the cursor on the top of the new channel layer and click, hold and drag the cursor to the bottom of this layer, creating a graduated white-to-black channel layer. Go back to the Channels window and click in the RGB layer at the top. This will hide the new channel you just created, showing the original image. Now, go to Filter > Blur > Lens Blur. For Depth Map Source, choose Alpha 1, the name of the new channel you created earlier. You’ll see your image, but with selective focus applied. To choose what area you want sharp, simply put the cursor on that spot and click. This area will become sharp and the rest of the image gradually will blur away from it. You can control the amount of blur by changing the Radius amount; the smaller the Radius, the less blur is applied. The sharpness applied in this example will be a horizontal line. If you want a vertical line of focus, apply the gradient from left to right. This technique results in blurs similar to using a tilt-shift lens.
Some software companies have developed programs that simplify the process of creating selective focus. One of my favorites is Alien Skin Bokeh. Bokeh refers to the quality of the blur in out-of-focus areas in your image. Some lenses produce pleasing bokeh, while others don’t. This program allows you to control the amount and quality of bokeh and apply selective focus/blur wherever you want. Alien Skin Bokeh is a plug-in requiring newer versions of Photoshop and Photoshop Elements as the host program. onOne Software offers FocalPoint 2, another Photoshop plug-in, which also creates selective-focus effects.
Select the Focus or Target the Blur?
When do you use creative focus? Whenever you want to direct the viewer’s attention. The eye normally goes to in-focus areas before going to out-of-focus areas in an image. This is why portrait shooters often blur the background around their subject. Creative focus also can add mystery and mood to images, especially landscapes.
On the other side of the equation, instead of using the tilt movement to add blur, you also can use it to increase depth of field and sharpness. Imagine photographing a field of purple columbine leading to a distant tranquil mountain lake. In order to get everything sharp from the columbine at your feet to the lake in the distance, you would use ƒ/22 to maximize your depth of field. Then, by tilting the lens plane downward, you make the plane of focus more parallel to the ground, increasing the amount of depth of field you achieve at ƒ/22.
Using creative focus is an artistic decision made by the photographer. Some images look great with blurred areas, while others need everything tack-sharp to be effective. Select the focus or target the blur—you make the call!
Tom Bol is a freelance editorial and commercial photographer based in Colorado. You can see more of his photography at www.tombolphoto.com.
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