PTLens is software that corrects lens pincushion/barrel distortion, vignetting, chromatic aberration, and perspective. The following are supported:
View examples of PTLens at work and download the software for a free 10 image trial. See a review for PTLens at Digital Outback Photo and articles in Dutch, German, French, Italian, and Japanese. PTLens is designed to correct distortion in architectural photographs as illustrated in Jeff Lynch's blog and Ian Bramham's published image.
PTLens is the first application to automate distortion correction. It all started on August 20, 2002, when I posted the following message in a news group:
What I need is a batch program that reads EXIF information from a JPEG file, looks up the closest match in a table, and automatically corrects for distortion. Well, I can dream, can't I?
Nobody volunteered so on September 19, 2002, I released version 1.0 of PTLens. Several years and 30,000 lines of source code later PTLens has evolved from a simple DOS command-line program to an easy-to-use application and Photoshop plug-in that corrects distortion, vignetting, chromatic aberration, and perspective.
The "table", referred to in the above quote, consists of more than 2400 separate calibrations — far more than any other application. Site DpReview has compared PTLens with DxO and Photoshop CS2 (I've since improved vignetting).
As a developer I subscribe to the Unix philosophy: Write programs that do one thing and do it well.