There's some amazing software out there for panoramic photography. Various software packages warp, stitch and blend sequences of photos so that they (ideally) look like one big, high-resolution, panoramic shot. However, getting these shots to turn out perfectly isn't easy when handholding your camera or using a normal tripod, especially when some parts of the image are fairly close to the lens.
The issue is "parallax", or, to rip something out of the American Heritage dictionary since I'm not about to try to explain it myself, "an apparent change in the direction of an object, caused by a change in observational position that provides a new line of sight." To fix this, you need to get the camera to rotate about a specific point that is forward of the screw socket in your camera.
Panoramic heads can be very expensive in the $300 to $500 range for "name brand" heads. Several designs for closer to $100 are available on the web, but look a tad on the flimsy side.
Building your own panoramic head for an SLR isn't too hard or expensive. The parts for the design shown here cost about $10. Every part here is available at a store like Home Depot.
Once you get past some of the misinformation out there, the only really hard part is figuring out the dimensions. The downside is that the mount is only useful for a specific camera/lens combo. On the other hand, you can't mistakenly mess up one of the critical adjustments once you've built it, and the homemade mount is as light as a couple small pieces of wood.
My woodworking skills aren't top-notch, but there's really not much need to make it look even this nice. Don't worry about appearance, just get the key measurements close and you'll have a fully functional new toy.
Step 1: Theory and Speculation
1. The point the camera must rotate about is the "entrance pupil", not the nodal point as is often stated. Better yet, who cares what they call it, there's a test to figure it out.
2. The rotation point (entrance pupil) is NOT necessarily halfway down the lens. In fact, on many cameras, it's not even close to that.
So, what's the test to find the entrance pupil?
Our mount will hold the camera sideways, but for now it's easiest just to hold it horizontally. Position two objects on a table so that they line up when viewed through your lens a couple of batteries work perfectly for this. Now pan your lens right and left as you normally would. You'll see the objects move relative to each other that's parallax.
Now, let's find a better pivot point. Put the tip of the index finger of your left hand somewhere along the bottom of the barrel of the lens. Now rotate the camera about that point. Try to hold that left hand as steady as possible (c'mon, you're a photographer, you got steady hands, right?) Still see a shift? Move your finger/pivot point along the lens until that shift goes away. On my Canon 17-85 EF-S, the point was 4 1/8 inches forward of the screw socket.
This photo shows the camera straight ahead, and the batteries aligned:
Now the camera is turned to the side. The alignment is quite close, but not perfect - we can see the left edge of the rear battery poking out:
Step 2: Cutting
- The base
- The side
- The arm
- The swivel
The swivel is optional. If you're using a tilt and pan head, skip it. However, if you have a ball head, it's a lot easier to include it than try to adjust the ball head every shot.
First, cut a piece of wood for the base. Use a piece of very flat, thick (5/8" or so) oak plywood or a plank of hardwood. Make it about 5" by 4" (12 cm x 10 cm). Next, cut the side. To make sure the camera has enough clearance when you swing it down, make it a little over 5" tall. The width would be the same 4" as the base. Line up the two 4" edges so that the side is sitting on top of the base to form an "L" (see the picture above). Drill holes up through the bottom of the base into the side and screw the two together. A little glue and maybe some bracing might help this less flex the better.
Step 3: Drilling
The first hole needs to go in the base -we need to drill a hole near the center. The exact distance from the side is critical it will need to run through the center of the lens. So, put your camera down on a table. Measure the height from the table to the center of the lens that's the distance the hole in the base needs to be from the side.
If you're not using a swivel under the base, you'll need a fairly large hole here, as you'll need to install a socket (or insert nut) so the tripod can screw into the tripod head. The dimensions of that socket depend on your tripod if you're planning to mount this to the screw that normally attaches to the camera, you want a 1/4-20 socket. Here's what an insert nut looks like:
The hole in the side is where the arm will pivot. As such, it needs to be in the same plane as the hole in the base. In other words, if you're looking at the unit from the side, the side hole will appear directly above the base hole. Make the hole in the side about 4 1/2 to 5 inches above the base your camera will need room to swing downwards when you're shooting a picture of the sky.
Step 4: Cont.
Drill a hole at one end for the arm to attach to the side piece where it will pivot. Drill another hole 4 1/8 inches (or whatever your measurement is) down the arm towards its other end. This last hole is where the camera attaches, so it needs to be 1/4" wide. Insert a 1/4-20 thumb screw through this hole (1/4-20 means 1/4 wide, with a thread pitch of 20, which is the most common pitch).
Now, attach the arm to the side. You'll need a flathead machine screw you may have to gouge out a bit of the hole in the arm so the full head can sink into the arm and not hit your lens:
Push the screw through the arm, then through the side, then use a washer and a wingnut to secure it.
Step 5: Finishing
Finally, you need to install a socket or insert nut as described above for the base section. Position it as near as possible to the center to maximize stability.
Sand all the parts. To finish things up, you can varnish, seal or paint, but don't get any of it on the rotating surfaces they'll stick every time you adjust the arm or swivel. Attaching a small level is highly recommended.
That's it, we're done!
When using your new panoramic head, remember that it never pivots at the point where the camera is screwed into the arm that joint stays put. Pivot at the arm and base as necessary, overlapping 20-50% between shots.
But regardless of what you use, this new tool will make the stitching far easier and more accurate. For example, this panoramic was stitched together from 9 shots:
The full size image was 32 megapixel, yet it stitched together without any error bigger than a single pixel! The image had no blending, yet the only seam that you can see (just to the right of the path) is due to an exposure error - it clouded up a bit on me in the middle of the sequence.