Lens Calibration is doing the rounds again, and is something that should be considered as you get more serious about your photography. While there are some pretty good solutions out there which are worth looking at: links below; please remember there are also low tech/cost ways of achieving the same outcome as some of the so called profi tools.
This video is not in English, but it is detailed enough to combine what you see with other information already out there. Enjoy.
