For those Canon users who are familiar with the Magic Lantern firmware enhancement software who are looking for a "set and forget" (other than removing and replacing the filter at the appropriate time) solution, I have written the following script. It:
- Calculates the intervals to take an arbitrary number of partial phase images, both in the C1-C2 and C3-C4 periods.
- Includes a configurable "margin" time, so that the first and last interval images are "interesting".
- Allows for exposure bracketing of the partial phase images. Configurable number of brackets and f-stops.
- Fires a configurable "burst" of images at C2 and C3. Depending on your camera's buffer, you can adjust how far before C2 and C3 this burst starts, so that you can be sure of coverage.
- During totality, will run through a configurable range of exposures as many times as possible. Minimum and maximum shutter speed, as well as the f-stop step size can be specified.
- Image times are calculated based on clock time, not by intervals between shots, which means that if you need to restart the camera (to change a battery, late setup, or other issue) the sequence will begin to execute at whatever image is appropriate for the current time.
- Has a test mode, which will run through a given sequence (starting at 00:00:00 when the camera powers on) without activating the shutter.
To use it, you'll need a supported Canon body, and (unfortunately) the beta "lua_fix" build of Magic Lantern. The "burst mode" function call is not yet supported in the mainline versions. Just open the script on a computer, fill in the constants (contact times, bracketing options and exposure details) near the top, and then save it to the "/ML/scripts" directory of your camera media. The just run the "Eclipse Magic" script from the appropriate ML menu tab.