I don't often discuss technical matters here, but this is a piece of news that will have a real impact on the way I work. In the latest updates of Photoshop/ACR, and Lightroom, a large selection of Pentax DA and DA Limited lenses are now supported for automatic correction of optical problems like barrel distortion and vignette. It's possible to correct these problems quite well using manual tools, but especially with distortion it's a drag because you not only need to apply the corrections but then also crop each picture afterwards. I never managed to make a batch action that would automate the process.
Here is a shot that appeared on this blog last spring. Shot with the 21mm, a lens with generally lovely image quality, but annoying barrel distortion. With all the action going on, I was willing to "live with" the distortion.
Now here is the same RAW file with auto-correction enabled in Adobe Camera RAW:
The formerly distorted straight line formed by the bright shop window frames is greatly improved. Corner vignette has also been lessened. Now, vignette isn't always a bad thing—in the old days lots of expert photographers routinely "edge burned" their prints under the enlarger to lead the eye into the center of the frame where the main subject tended to be—but starting out with a file that by default has low distortion and even illumination across the whole frame seems like the right idea to me. The software automatically recognizes the lens and applies the appropriate corrections, you only need to hit an "enable" button in the Lens Corrections panel of ACR, and it should be possible to save that as part of a custom default.
The "stack of pancakes" (DA limited compact lenses designed for digital imaging, at 21mm, 40mm, and 70mm) as well as the 15mm, 35mm Macro and also the older, pre-digital set of Limited lenses (31, 43, & 77mm for standard 35mm film format) are all supported. I haven't had a chance yet to see if the automatic correction also addresses chromatic aberration but expect that it does. I also haven't had a chance to see whether there is any trade-off for these corrections, like reduced resolution, but based on the results I've been getting with the Panasonic GF1—which had automatic ACR corrections for the 20mm lens from the get-go—I expect the results to be positive. I also expect I'll be using my Pentax equipment more now than I have been for the past few months, during which the GF1 has taken over nearly all my shooting.