Tilting back

[James Irelan]

Joost and John

Although I never found out how to correct my first panos that I wrote you about, it was no big deal because they weren't much much of shots to start with. They were just tests.  But now I have moved on to new ones, and these are coming out perfectly.  They look great.  

One question you could help me with:  I recently took some shots of some wide buildings.  The shots look fine, but the buildings look like they're leaning back ever so slightly.  You can see the distortion more at the building's sides- a very slight keystoning- not enough to ruin the shot, probably most people wouldn't even notice it, but I do.  I'm shooting with a 77mm lens, and I'm using a Acratech pano head on an Acratech leveling base, at approximately chest level, so I don't know how the distortion is being introduced.  As I say, it's slight, but if I could correct it, I would, if you know how I could do that if it could be done.  If I were using a wider lens, I would assume that I'm not square on to the building, but with the 77mm I don't assume that. 

thanks

James Irelan

San Antonio Texas

[John Houghton]

James, Have you tried levelling the panorama using vertical line control points on the sloping vertical edges of the building?

John

[James Irelan]

John,

Hmm, the farthest I've gotten with control points is that I finally yes, managed to place a couple successfully, but that's about it.  So no, I have not tried leveling a vertical line with them.  So I place control points on the edge of a wall?  and then what? There's some vertical line I can  map them to?

James

[John Houghton]

James, Go to the PTGui web site and select the Video Tutorials option under the "Learn" heading.  Then scroll down to Part 8 - Levelling.  

John