Compensate for Your Camera Automatically
Almost every camera lens distorts the image you’re shooting. While sometimes the image distortion is the effect you want, often the curving of lines that ought to be straight just looks wrong. The Lens Correction in CS5 is a filter rather than processing you can apply directly to camera RAW files at this point (although Adobe tells us it's a future feature). However, it does use the profile of the lens in your camera to apply corrections for the specific distortions your camera and lens tend to introduce. As well as geometric distortion (the barreling out and pin-cushioning of lines that should be straight), the filter can automatically correct chromatic aberration, such as the purple fringe of color along edges that can happen if you shoot in bright sunlight, and vignetting.
You need a lens profile to use the automatic corrections. If you don’t have one you can click through to the Custom pane and adjust the sliders. This can fix very obvious problems with dark corners and color fringes while subtle tweaks to the geometry can improve photos dramatically. However, you can end up with white areas at the edge of the image you need to crop, while the automatic corrections seem to take care of that automatically.
There are only a few profiles bundled for key camera manufacturers: Nikon (the 3DX and Coolpix P6000), Canon (two EOS models), Sony (A700 and A900)), and Apple (the iPhone 3G and 3GS). The iPhone is so popular and the iPhone camera so in need of correction that this feature is very welcome. However, it only applies to the main DSLR makes and the iPhone and doesn’t cover third-party lenses. Owners of most other cameras will feel left out.
To expand the coverage of camera profiles, Adobe will offer a Lens Profile Creator that you can download free. With it, you can take a set of photos of the camera-calibration chart displayed on screen and the tool will create a custom profile. You can use the tool for each lens and this will tell the lens-correction filter how your camera and lens distort a known image. However, your camera has to have a calibrated screen to take advantages of this feature (another reminder that Photoshop is aimed mainly at creative pros).
There’s a Search Online button in the filter that looks for other lens profiles on the Labs site and you can click through multiple profiles to see which gives the best result. If the profile tool takes off and lots of users create custom profiles, you might get one for your camera. Ideally, camera manufacturers would see the value and supply professionally created profiles to work with this. With the right profile, you could get much better shots out of a point-and-shoot pocket camera.