How do you stop tall buildings looking like they're leaning

[JimBowen1]

This is probably a dumb question, but how do you stop tall buildings looking like they're leaning away from you, if you're near the base of the building?

I get that if you're tilting your head back to take a photo, the lens is positioned in such a way that the top of the building will seem as if it's learning back from you. In addition I get that you can counteract that lean by standing further away from the base, flattening the angle between the camera and the top of the building (and zooming in from there), but is there another way of doing this?

I ask because we visited New York over the summer want wanted to take pictures of skyscrapers (what can I say we're easily impressed where we're from), but when we looked at them we were a little underwhelmed at some because of this problem.

[rjseeney]

Perspective distortion is a common problem in many lenses, especially wider angle lenses. It's handled pretty easily with editing software. I use PTLens. It will crop some of the image...the more distortion, the more cropping you will have to do.

[TCav]

If you do ita lot, Canon has its Tilt-Shift Lenses, and Nikon has its Perspective Control Lenses.

For ocassional use, software is a good solution, but the effect is acheived by playing with the pixels and the result can often be a softer image.

[BillDrew]

JimBowen1 wrote:

This is probably a dumb question, but how do you stop tall buildings looking like they're leaning away from you, if you're near the base of the building? ...

Not dumb, but often asked. As noted by rjseeney & TCav noted, the issue is perspective distortion. You will find lots of info on the subject once you know what it is called.
JimBowen1 wrote:

... I get that if you're tilting your head back to take a photo, the lens is positioned in such a way that the top of the building will seem as if it's learning back from you. ...

Exactly correct. To get rid of that kind of distortion the film/sensor should be parallel to the surface you want in undistorted form. The tilt/shift movements of view cameras allow that. The thing to keep in mind is that a tilt will also change the plane of focus so for architectural purposes you will almost always want to only use the shift.
JimBowen1 wrote:

... In addition I get that you can counteract that lean by standing further away from the base, flattening the angle between the camera and the top of the building (and zooming in from there), but is there another way of doing this? ...

Yes - simply keep the camera's sensor vertical (no tilt) and crop away the bottom latter. If you also want to avoid perspective distortion in the horizontal direction, you must stand in a place such that the sensor is parallel in both the horizontal and vertical direction.

As sjreeney noted, software is another way to deal with the issue. Since only moderate perspective correction can be done without other odd effects becoming obvious, software is adequate unless you are going to make very large prints - in which case you should get a camera designed to deal with the issue like a large format view or field camera. Those, with a lens having enough coverage to deal with a large amount of shift, get very expensive very fast.

The focal length of the lens has nothing whatsoever to do with the problem. It does seem that wide lenses cause more problem, but that is only because the camera is closer to cover the same vertical height so requires more tilt to keep the whole building in the frame. That can easily be tested by putting your camera on a tripod tilted back. Shoot once at the wide angle of your zoom and another at the longest. Compare the distortion in a detail captured with the long end, e.g., a window. You will find that the distortion is exactly the same.

[JimC]

Here is a tutorial on perspective correction using Hugin (a GUI front end for Panorama Tools):

http://hugin.sourceforge.net/tutoria...ctive/en.shtml

See more about it here:

http://wiki.panotools.org/Hugin

Download the latest betas from here:

Windows

• Hugin,(includes latest Enblend/Enfuse) 24-May-2008 SVN3082[/*]
• Enblend/Enfuse 26-Feb-2008[/*]
• MD5 Checksums[/*]
• enfuseGUI[/*]

OSX

• Hugin, Enblend/Enfuse Packages, includes GUI front end.[/*]
• Alternative Enblend/Enfuse[/*]

Linux

• Ubuntu[/*]
• Fedora[/*]
• OpenSUSE[/*]
• Gentoo[/*]

[BillDrew]

I agree with JimC's suggestion of Hugin for perspective correction. If you want more hand-holding and don't mind paying a bit of money there are some shareware front-ends for Panorama Tools (PTGui, PTAssmber, PTMac).

Panorama Tools (with any of the front-ends) will do a great deal more than that and thus is not easy to figure out. Well worth the effort.

[VTphotog]

Shoot, I guess I have got to get with it. I just use a big jackon the backside of the building.:lol:



brian