Friday, August 24, 2012

Panoramic Head - prototype

A friend recently sent me a link to a panoramic photo of Mars, stitched together from a bunch of images from the Curiosity rover that landed last week.  It was as close to I'm likely to get to the experience of really seeing the place, and that got me interested in making panoramic images of my own, of cool places that I have actually been to.

There is free software to stitch images together, but it works a little better if you take all the photos by pivoting the camera around a particular point in space, usually called the nodal point or entrance pupil.  That point is generally near the center of the camera's lens, so a regular tripod doesn't quite cut it because it rotates around the tripod socket under the camera body.  It's also typical to take photos with the camera in portrait orientation (sideways) to capture the vertical dimension as widely as possible.

Enter the panoramic head.  Yeah, sure, you can buy them, but that's not how I roll.  I made a bunch of sketches and here's the first iteration of a working design.  The goal is to have two axes of rotation that intersect at the nodal point of the lens.  This prototype is nothing fancy, just some scraps of plywood and some nuts and bolts from the hardware store.  I tacked it together last night and took a quick set of pano shots of our living room.  They stitched together nearly perfectly, much better than a similar set of shots I took with the tripod alone.  So yay.  Not so yay are some of the details.  The base plate needs to be bigger, and the elevation arm can't swing down to 90˚ to take a shot straight up because of the way the camera is attached to it.  I also didn't take time to rout the groove in the elevation arm that will allow adjustment for different nodal point positions.

Canon 50D with 10-22 zoom on my plywood panoramic head.
The idea is to allow pivoting about the nodal point (white) in two axes: azimuth in red, and elevation in blue.  The green rotational axis is fixed.

Round two of the design will be a lot better.