Panoramic stitching

We’re in the first heat wave of the summer here in Seattle, which makes me happy to retreat to the cool, dark basement and work on the files from my latest shoot. Since one of the goals was to get "campus beauty" shots, I took along the panoramic rig.

I am doing stitched pans these days, using a Really Right Stuff panoramic base. What this gizmo does is twofold. One, it lets you rotate the camera around the lens nodal point, which eliminates parallax problems with stitching. And second, it is self leveling. You don’t have to level your tripod, just the pan base. If you use an L-bracket, you can shoot with the camera mounted vertically, which is brilliant for anything doing with architecture.

This shot here I did on a bright, sunny afternoon, dreadful conditions for digital. I knew I’d have to go down the HDR (high dynamic range) road if I was to get both detail in the shadows, and anything in the brilliant, sunlit collonade in the background. I exposed at 1/50 at f/11 for the shadows, and 1/200 at f/11 for a midtone capture, and 1/500 for the bright sun. The sweep is five exposures, so I shot it 15 times.

I have a program, Photomatix that is great for making quick and dirty HDRs. But there was a breeze blowing, and the kids didn’t remain rock steady, so that program wouldn’t work without getting major double-exposure ghosting. I had to stack the exposures manually in Photoshop, and do my combined exposure images by brushing in the masking. I duplicated these files as single layer tifs to compose the pan.

I use PTGui for stitching my pans. The great feature with this program, besides the brilliant job it does with the stitching control points it automatically finds, is that you can output a full size, layered Photoshop file. Where the program makes mistakes in the stitching (people walking through the exposure boundaries often end up as semi-transparent ghosts), you can fix by brushing through the masks on the individual layers.

If you click on the photo, you’ll open up a large version.

Comments

[Joe Gaylor]

Doug, brilliant work.. Great Job

[Martin Doonan]

Have you tried the Smartblend plug-in for PTGui? I find it eliminates the ghosting and can also deal with some fairly large parallax problems if you're not using a pano base. It's so good, it's my default for stitching, although it adds a bit of time to the processing. Robust for really big files, too.