Tuesday, February 8, 2011
Using Lens Profiles
Correct a variety of distortions with Adobe’s extensive database of lens information
Adobe’s lens profile corrections are amazing. Lens Corrections automates correction of standard lens distortions, including geometric distortion, chromatic aberration and vignetting. This feature also can be used to adjust perspective and rotation. Adobe provides support for a growing list of camera manufacturers, camera models and lenses—Canon, Nikon, Pentax, Samsung, Schneider, Sigma, Sony, Tamron and Zeiss.
1) Lightroom’s Manual Lens Corrections tab.
You can access Adobe’s Lens Corrections in three locations—Adobe Camera Raw, Lightroom 3 or Photoshop CS5’s Lens Corrections filter. Lens profile corrections were first introduced in Lightroom 3. To get lens profile corrections in Adobe Camera Raw CS5, you need to download a version that has been updated after the release of Lightroom 3. You can download the latest free update at www.adobe.com/products/photoshop/cameraraw.html.
It’s far less destructive to make these types of adjustments to raw files during conversion rather than after conversion; it’s also more flexible. Use a smart object and go back to the controls anytime by simply double-clicking the smart object. However, if you want to apply Lens Corrections within Photoshop after a file has been rasterized, you can use CS5’s updated Lens Corrections filter.
2) Distortion at maximum.
Checking Enable Lens Profile Corrections also will allow you to access three sliders—Distortion, Chromatic Aberration and Vignetting—for manually fine-tuning the results. If you like the results of one correction but not another, you can decrease or increase the effects in one or more of the three fields. Under Manual, you’ll find controls for visually creating your own lens profile corrections.
Vignetting offers two sliders: Amount, or the intensity of the adjustment, and Midpoint, which is designed to control the way the effect fades off. Chromatic Aberration offers two sliders: Fix Red/Cyan Fringe and Fix Blue/Yellow Fringe, plus a Defringe drop-down menu with three options: Off, Highlight Edges and All Edges. The Defringe menu options can be used to target the adjustment more precisely. Highlight Edges is particularly useful for defringing images with strong specular highlights.
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