Electronic panorama head with rotation sensor

In my quest for the idea panorama head, I have recently written up some design notes and reviews. I found that the automatic head I tried, the beta version of the Gigapan turned out to be too slow for my tastes. I can shoot by hand much more quickly.

Manual pano heads either come with a smooth turning rotator with markers, or with a detent system that offers click-stops at intervals, like 15, 20 or 30 degrees. Having click-stops is great in theory — easy to turn, much less chance of error, more exact positioning. But it turns out to have its problems.

First, unless you shoot with just one lens, no one interval is perfect. I used to shoot all my large panos with a 10 degree interval which most detent systems didn’t even want to support. Your best compromise is to pick a series of focal lengths that are multiples. So if you shoot with say a 50mm and near-25mm lens, you can use a 15 degree interval, and just go 2-clicks for 30 degrees and so on. (It’s not quite this simple, you need more overlap at the wider focal lengths.)

Changing the click stops is a pain on some rotators — it involves taking apart the rotator, which is too much no matter how easy they make that. The new Nodal Ninja rotators and some others use a fat rotator with a series of pins. This is good, but the rotator alone is $200.

Click stops have another downside. You want them to be firm, but when they are, the “click” sets up vibrations in the assembly, which has a long lever arm, especially if there is a telephoto lens. Depending on the assembly it can take a few seconds for those vibrations to die down.

So here’s a proposal that might be a winner: electronic click stops. The rotator ring would have fine sensor marks on it, which would be read by a standard index photosensor. This would be hooked up to an inexpensive microcontroller. The microcontroller in turn would have a small piezo speaker and/or a couple of LEDs. The speaker would issue a beep when the camera was in the right place, and also issue a sub-tone which changes as you get close to the right spot — a “warmer/colder” signal to let you find it quickly. LEDs could blink faster and faster as you get warmer, and go solid when on the right spot. They would also warn you if you drifted too far from the spot before shooting.

Now this alone would be quite useful, and of course, fully general as it could handle any interval desired. Two more things are needed — a way to set the interval, and optionally a way to ease the taking of the photos.

To set the interval, you might first reset the device by giving it a quick spin of 360 degrees. It would give a distinctive beep when ready. Then you would look through the viewfinder and move the desired interval. Your interval would be set. If doing a multi-row you would have 2 sensors for angle, and you would do this twice. You could have a button for this, but I am interested in avoiding buttons. Now you would be ready to shoot. It would give a special signal after you had shot 360 degrees or the width of the first row in a multi-row. Other modes could be set with other large motions of the rotator, such as moving it back and forth 2 times quickly, or other highly atypical rotations.

(If you want buttons, an interesting way to do this is to have an IR sensor and to accept controls from other remotes, such as a universal TV remote set to a Sony TV, or some other tiny remote control which is readily available. Then you can have all the buttons and modes you want.)

We might need to have one button (for on/off) and since off could be a long press-and-hold, the button could also be used for interval setting and panorama starting.

The next issue is automatic shooting or shot detection. The sensor, since it will be finely tuned, will be able to tell when you’ve stopped at the proper stop. When all movement ceases, it could take the shot without you pressing the shutter using a bunch of methods. It might also be useful to have you manually control the shutter, but via a button on the panohead rather than the camera’s own shutter or cable release. First of all, this would let the head know you had taken the shot, so it could warn you about any shot that was missing. It could also know if you bumped the head or moved it during any shot — when doing long exposures there is a risk of doing this, especially if you are too eager for the next shot. Secondly, you should always be using a cable release anyway, so building one into the pano head makes some sense. However, this need not be included in the simplest form of the product.

One very cheap way of having the pano head fire the shutter is infrared. Many cameras, though sadly not all, will let you control the shutter with infrared. Digital SLRs stopped doing this for a while, but now Canon at least has reversed things and supports infrared remote on the 5D Mark II. I think we can expect to see more of this in future. Another way is with a custom cable into the camera’s cable release port. The non-standard connectors, such as the Canon N3, can now be bought but this does mean having various connector adapters available, and plugging them in.

A third way is via USB. This is cheap and the connector is standard, but not all cameras will fire via USB. Fortunately more and more microcontroller chipsets are getting USB built in. The libgphoto2 open source library will control a lot of cameras. Of course, if you have a fancy controller, you can do much more with USB, such as figure out the field of view of the camera from EXIF but that’s beyond the scope of a simple system like this.

The fourth way is a shutter servo, again beyond the scope of a small system like this. In addition, all these methods beg more UI, and that means more buttons and even eventually a screen if an LED and speaker can’t tell you all you need. However, in this case what’s called for is a button which you can use to fire the shutter, and which you can press and hold before starting a pano to ask for auto firing.

The parts cost of all this is quite small, especially in any bulk. Cheaper than a machined detent system, in fact. In smaller volumes, a pre-assembled microcontroller board could be used, such as the Arduino or its clones. The only custom part might be the optical rotary encoder disk, but a number of vendors make these in various sizes.

I’ve talked about this system being cheap but in fact it has another big advantage, which is it can be small. It’s also not out of the question that it could be retrofitted onto existing pano heads, as just about everybody is already carrying a ballhead or pan/tilt head. For retrofit, one would glue an index mark tape around the outside of your existing head near where it turns, and mount the sensor and other equipment on the other part. The result is a panohead that weighs nothing because you are already carrying it.

Update: I am working on even more sophisticated plans than this which could generate a panohead which is the strongest, smallest, fastest, most versatile and lightest all at the same time — and among the less expensive too. But I would probably want some partners if I were to manufacture it.

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