| |
 |
| © Darwin Wiggett |
| Click photo to see more images. |
We blame it on the prairies.
We live in an area with horizon-to-horizon views where the land stretches to infinity and the sky soars high above. Photographing this expanse of sky and land is difficult, even with superwide-angle lenses. In the past, we had to choose between capturing a sliver of land with the big sky above, or a sliver of sky with the big landscape below, though not both in the same photo.
But with digital cameras, it dawned on us that we could easily stitch together two photos, one of the sky and one of the land, to give us the big expansive views we love in a single photo.
Sky stitches are very easy to blend, because the area of overlap (the sky) is amorphous and indistinct, making errors in image alignment easy to mask. A side benefit is that the files are large and can be printed really big.
Sky stitches are easy to capture in the field, and relatively simple to combine in image-editing software. Here is how we do it.
Skinny or square?
If you photograph a scene with your camera in vertical format, then the final resulting image will be a narrow, tall, rectangular panorama. If you hold your camera in a horizontal format, then the final composite will look like a square.
The choice of whether to go skinny or square often can be dictated by the subject matter: Large square images will give the photo a sense of stability and work well with stationary objects, whereas narrow verticals can provide a forced perspective and exciting energy.
In the field
 |
| © Darwin Wiggett |
Sky stitches can be made with any camera or lens. We have even made them using telephoto lenses, but we usually find that wide-angles give us the best results.
Look for interesting skies that have some character or drama in the clouds. We try to create compositions with diagonals across the frame to help move the eye though the entire picture space. We also look for foreground elements that continue the sense of movement created by the clouds or that mirror the patterns and shapes happening in the sky.
Once you've decided on your foreground and sky, mount your camera on a tripod and tilt it up and down to get a sense of composition. Adjust your zoom to achieve the necessary coverage -- remember that the focal length must be the same for both photos.
Start with the foreground landscape, but include enough sky to fill at least 20 percent. Make sure that no foreground elements such as trees or rock formations extend into the sky beyond the top of the frame -- they will be hard to align in the final stitch.
Expose for the foreground and check the histogram to make sure you've lost no highlight or shadow detail. Make exposure adjustments as necessary, and if the sky is very bright relative to the land, use a split neutral-density filter to even out the exposure.
After you shoot the land, tilt your camera up, this time keeping at least 20 percent of the land. If you're using an ND filter, reposition it to be sure the gradient lines up with the horizon's new position.
In the computer
 |
| © Samantha Chrysanthou |
Any software that allows stacking of images on separate layers will work to make sky stitches. If you have Adobe Photoshop CS2 or CS3, you can use the Photomerge command to do stitches automatically. In CS3, choose File > Automate > Photomerge.
Set Use Files and click Browse to select your two images. At the bottom of the dialog box check Blend images together. In the Layout section we almost always use Reposition Only because this gives us the most amount of each picture area possible. Now click OK, and Photoshop will build the sky stitch. The results are often perfect, but if it's not what you expected, retry the stitch in Photomerge using the Auto setting in the Layout dialog box.
Once Photomerge gives you what you want, look at the picture at 100-percent view and scroll to check the seam. (At smaller magnifications, sometimes it will look as though there is a break in the seam, but once you zoom back to 100 percent, the seam usually disappears.)
If all looks as it should, flatten the layers (Layer > Flatten Image) and save your picture. Finish the photo as usual by adjusting color, saturation and contrast. If the stitch did not work, you can try doing it manually in Photoshop using layers and layer masks. See www.PopPhoto.com/SkyStitch for detailed step-by-step instructions.
If you don't want to use Photoshop, you can find inexpensive (or free) panoramic stitching software that will usually blend the two images well -- and automatically. We sometimes do this using the PhotoStitch software that's included with many Canon cameras.
If you use PhotoStitch, we recommend merging the images using the Images Scanned in Sections setting; the Panning setting often loses too much image to the correction of parallax errors.
|
