The final version of Lightroom 3 (and ACR 6.1) will allow us access to lens-correction features that have long been lurking.
Distortion correction has been around for a while in Lightroom
For some compact cameras that shoot raw and for some Micro Four-Thirds camera-and-lens combinations, both Lightroom and ACR have been providing behind-the-scenes corrections of lens distortion. Users of the Canon S90, the Panasonic Lumix LX-3 and some wide-angle Micro Four-Thirds lenses (such as the excellent 20mm Panasonic f/1.7) have seen automatic correction of very significant barrel distortion but Lightroom 3 (and ACR 6.1) will extend that benefit, in some form, to the rest of us.
Control over the degree of correction
Many users of the cameras and lenses mentioned above probably didn’t even know that their images were being corrected, sometimes for an eye-popping level of geometric distortion. The feature just worked, unbidden, behind the scenes. Adobe’s engineers generally seem to have matched the correction that the camera manufacturers applied to JPEGs generated by the camera and/or the results produced by the raw converters shipped with the cameras, meaning that by design, images from cameras like the S90 and LX-3 show some residual level of barrel distortion after automatic correction within Lightroom—correction over which the user has had no control, till now. With Lightroom 3, we’ll be able to fade the degree of correction for things like vignetting and distortion.
The best bit: we’ll be able to profile our own lenses
Out of the box, the lens-correction feature will support some lenses from Canon, Nikon and Sigma (who even issued a press release about it) but potentially the strongest aspect of Adobe’s implementation is that we will get a mechanism to allow us to profile our own lenses for optical defects. There are other solutions to the lens-correction problem (DXO Optics Pro, for example, or PTLens) but Adobe’s looks like it might be the strongest so far for a couple of reasons: firstly, the existence of an easy way to profile your own lenses (the proof of the pudding will be in the tasting, of course) and secondly, the apparent concern of the Adobe Lightroom/ACR team to get local corrections working well with this new feature. This is harder than it sounds: say you’ve removed a spot of sensor dust from an image or you’ve added saturation and sharpness to a an area of a photograph: quite how should Lightroom react when you later switch on the automatic correction for lens for distortion? Should it even let you switch it on if you’ve applied local corrections?
Head over to Tom Hogarty’s blog post, where he shows how it’s all going to work. Congratulations to the Lightroom team on what looks to be an excellent implementation.