Digital Focus: Make a Panoramic Photo

By Dave Johnson, PCWorld Aug 6, 2002 1:00 AM

Feature: Create Your Own Panoramic Photos

So there I was, standing on Abbey Road, right in front of EMI's famed recording studio that produced a decade of The Beatles' historic music. I was a few steps from the zebra crossing pictured on the cover of the Fab Four's last record. How to capture it all?

I shot a panorama. My shot captured the whole length of the street, from the crosswalk at the corner to the steps that John, Paul, George, and Ringo traversed throughout the 60s. It's now a dramatic centerpiece for the Beatles' shrine that hangs on the wall in my office.

A panoramic photo is much wider or taller than traditional prints, and it consequently has a powerful impact on the viewer. You don't need a special camera to shoot a panorama--you can take these extra-wide shots with your existing digital camera. All you do is shoot a bunch of separate photos and "stitch" them together afterwards. You can do the stitching by hand in an image editor, or get a program that automates the process. I'll talk more about that later. For now, let's see how to ensure a good panorama right from the start, when you take the pictures.

Shooting the Panorama

It's certainly possible to shoot a good panorama by handholding the camera, but I suggest using a tripod if one is available. Remember that you're going to have to stitch all of these images together later into a seamless whole, and if the various images are a poor fit, that becomes more difficult and the panorama will suffer. All of the pictures should be shot with the camera level to the horizon, for instance--something that's easier to do with a tripod than your hands, for instance.

The trick to getting a good panorama is having enough overlap in each image. You want to shoot a picture and then rotate the camera slightly so you capture another segment of the scene to the left or right. You want to overlap the images so that there's between 25 and 50 percent of identical material in both shots. That way you or your software can line the images up more easily.

Shoot as many pictures as you need to capture the entire span of the panorama, remembering to keep the right amount of overlap in each image.

Combining Images With Software

Once you've taken your future panorama, transfer its component images to your PC. If you have panorama software, creating the final image is a drag-and-drop affair. Load the images into your panorama program, arrange them in the proper order, and let the computer do all the work. There are several programs that can do the stitching for you, and they're all quite adept. Even the least expensive panorama software does a better job than what you can do by hand, so I highly recommend trying one of these programs if you see a lot of panoramas in your future:

Not only do these programs stitch images together faster than you could do it on your own, but they also blend the overlaps from each picture together for smoother transitions than you can achieve by hand.

Stitching by Hand vs. Using Software

If you don't have a program that can create your panorama for you, fret not: You can do it yourself. After all, it's really just a matter of lining up a batch of images side by side. Panorama programs make lots of tiny changes to the pictures so they blend together better, but much of the time you can get decent results without all that extra digital trickery.

If you're lucky enough to take a series of photos in which absolutely nothing moves while you're shooting, you can get excellent results by combining images by hand. If you're shooting in a dynamic environment, with wind-blown trees or people moving through the scene, you can still get reasonably good results. Remember, though: Most of the time, your panoramas will probably have imperfections, so be prepared to accept some compromises. And for best results, turn the stitching duties over to automatic panoramic software.

Doing It By Hand

Start by calculating how large the finished image will need to be. If you shot five 640-by-480-pixel images, for instance, the finished panorama will be no more than 3200 pixels long.

If you're using Paint Shop Pro, create a blank image by choosing File, New from the menu. For five images, you'd make the width 3200, but make the height perhaps 30 percent larger than the images. You can always crop away unused white space at the end.

For our purposes, I've provided two images you can use for a small panorama. Since we have just two images in this example, you might want to make the panorama about 1000 by 600 pixels. Open these images in a browser, than save them to your hard drive:

left
right

Open the first image and copy it to the clipboard by choosing Edit, Copy. Then click on the blank image and choose Edit, Paste, As New Layer from the menu. Add all of the other images to the panorama in the same way.

Now it's time for the hard work. Pick one end of the panorama and line up that image with the picture next to it. You can line up the images more accurately, if you make one of them transparent. To do this, open the Layer Palette dialog box. (If it's not already on screen, open the Layer Palette by choosing View, Toolbars from the menu, then check the Layer Palette and click Close.) Hovering the mouse pointer over the slider lets you see which image is associated with each slider. Drag the transparency slider (it looks like a bisected hourglass) for the image in the "top" layer away from 100 percent. As you drag the slider to the left, you should see the image become somewhat transparent, revealing the layer underneath.

When the first two images are lined up to your satisfaction, set the transparency back to 100 percent and move on to the next image. Work your way across the panorama, lining up the pictures.

When the panorama is complete, you may find the top and bottom look kind of ragged. That's why we made the panorama image taller than the height of the individual pictures. Use the Crop tool (which looks like a picture frame in the toolbar) to make a perfectly rectangular image. Save your file--you've got a panorama!

How did yours come out? Mine looks like this.