Originally Posted by
ibis_ti
How do you compensate for lens distortions and parallax?
Lens distortion: I don't. I use my wife's expensive Nikon, doesn't seem to be a problem.
Parallax: This is less of a problem than you might think. Even with a viewing angle change of 5 degrees, the parallax error is 1 - cos(5) which is about 0.4% so a 550mm C to C seat tube might measure as 548 mm. Close enough for government work.