PTLens is software that corrects lens pincushion/barrel distortion, vignetting, chromatic aberration, and perspective. The following are supported:
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. For individuals who use Aperture on the Mac there is a well written article by Sascha Losko.
Modern computers often have processors that contain more than one core. Each core can work in parallel to handle computationally intensive tasks. To improve the performance of PTLens on your system choose Tools > Options (PC) or Preferences (Mac) and specify the number of threads on your system.
The following table illustrates the time it takes to process a 24MP (6000 x 4000 pixel) image on a system with a processor that has 4 cores and supports, via hyperthreading, 8 threads. The image was corrected for barrel-pincushion distortion and all sliders for Perspective, Vignetting, and Chromatic Aberration were enabled.
Processors Seconds 1 10 2 6 4 4 8 3 16 3
When only correcting for distortion it took less than 1 second when utilizing 8 threads. Specifying the correct number of processors improved performance by a factor of three. No benefit is gained by specifying more processors than supported by your architecture. There was no penalty either as the overhead for extra threads is minimal.
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.