How to make tall buildings look straight

Like most people, whenever I visit a new city, I like to take pictures of the architecture. And like most people's architectural photographs, mine feature buildings that look like they're falling backwards. The effect can be dramatic, but it's not what my mind's eye was seeing when I snapped the picture. Surprisingly though, it's what my eyes were seeing. When you look up to take in a tall building, vertical lines, such as edges of windows and walls, look parallel. But they're actually converging, at least to your eyes.

 

Try this experiment: look way up at a skyscraper or other tall rectangular structure. Hold your hands out in front of your face tracing the lines of the building. Your fingertips will point inwards as your hands follow the converg­ing lines of the structure.

Your brain knows that those ver­tical lines are parallel, so it reinter­prets the image as something it knows is correct. That's why the converging lines and falling-down buildings in city photographs look wrong. If only there were some way of correcting the images our cameras capture in the way our brains correct the images our eyes capture.

 

              

 

 

 

With a program like Photoshop Elements 3.0, it's easy to correct the perspective of tall buildings, like these ones on Fifth Avenue in New York.

 

 

 

 

 

 

 

 

 

There is, and it's dead-simple. Pretty well all image-editing pro­grams have transformation func­tions that let you stretch architec­tural images.

Here's how you do it with Adobe's new Photoshop Elements 3.0 software. First load the image into Photoshop Elements' image editor. You can do this by using the File ... Open dialog under the File menu. Or choose the image you want in Photoshop Elements' Image Browser, then click the Edit tab and choose Standard Edit.

Once the photo is loaded into Photoshop Elements' image editor, click on it and choose All under the Select menu (or use a shortcut key to select the entire picture: click on the image, and enter Control-A on a PC or Command-A on a Mac). Next, choose Transform and then Free Transform under the Image menu (or use the Control-T/ Command-T shortcut command). Your image will be framed in dot­ted lines, with grab-boxes in the corners and centers.

 

 

 

Straighten Up!

Here's where the magic happens. With your mouse pointer on a grab-box in one of the upper cor­ners, hold down the control key (command key on a Mac) and drag your mouse until the con­verging lines on that side look straight. Go to the other upper corner and do the same.

Depending on how much you've stretched the upper part of your image, objects in the foreground may look squashed. Female pedes­trians, for example, may look like linebackers. Buildings may look straight, but also shorter. To correct this distortion, put your mouse pointer on the grab box in the bot­tom centre and pull downward. Release the button when fore­ground objects look the right height and shape (if you've stretched the top a lot, you proba­bly won't get the foreground per­fect).

You may have to go back and forth a few times to get everything right. But with a little experience, you should be able to straighten tall buildings in under a minute.

 

 

Photoshop Elements' Transform function makes this leaning office tower in Pusan, Korea look more natural.

 

 

 

 

 

This Korean photographer is pointing his camera upward to take in the buildings. He'll like the results better if he fixes the converging lines on his computer.

 

 

 

When you're finished, press the Enter key (Return on the Mac) to lock in your transformation. You can see how I straightened a pic­ture I took of the Duomo (cathe­dral) in Milan, Italy on a rainy February day a couple of years ago. There are also before-and-after pix of some pictures I took in New York last fall, and in Korea in the fall of 2003.

Some people will prefer the "before" to the "after." The con­verging lines in the "before" pic­tures give a dramatic sense of urban enclosure that's missing in the "after" pictures. But the Transform function in Photoshop Elements (and other image editors) is a wonderful tool for big-city photography.

One last note: these transforma­tions involve cropping out part of the image, especially on the top at the sides. If you know you're going to be using your computer to alter the perspective of big-city architec­tural pictures, shoot a little wider if possible, so that you don't end up losing important picture content.*


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