Archived posting to the Leica Users Group, 2003/03/05
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]iI's easy to see barrel distortion in PS because you are comparing before/after with the same image. Subjects with lots of straight lines at the edge of frame will clearly show barrel distortion in the 1-2% range. Many people will find 4% unacceptable. On Wednesday, March 5, 2003, at 06:07 AM, Javier Perez wrote: > Gee I'm full of questions today. > Was wondering. Assuming you ar photographing a subject > with lots of straight lines, at what point does > optically induced distortion start to become apparant > in terms of percentage. I'm asking because I've seen > lots of wideangles with figures quoted in the 1 - 2% > region and I can't detect any distortion, barrel or > pincusion. On the other yhand if I add 1 percent > distortion to an image in photoshop it's easy to tell. > Is photoshop using optically faithful simulations of > distortion or is it something else. One of the reasons > I'm interested in knowing this is that I'de like to > undistort some images taken with my slightly better > than mediocre tokina 24-200 AT-X zoom which distorts > at almost every focal length but PS won't really > flatten them out properly. - -- To unsubscribe, see http://mejac.palo-alto.ca.us/leica-users/unsub.html