Some cameras allow for manual control of exposure times and focus. These work best when photographing the eclipse because automatic systems were never intended to compensate for the type of lighting available!

Older film cameras that use interchangeable lenses offer control of the exposure, focus, and f/stop. Newer cameras may only allow for changes between icons for scenery or portraits. In most cases the scenery settings will work best since the object being photographed is distant and the flash is certainly not needed. Experiment by taking pictures of the moon (see Practicing section) and sunsets to learn what camera setting works best.

Be sure to disable the flash before totality!

Cameras allowing for variable exposure times can capture more detail in the corona. Shorter exposures will show the inner corona, chromosphere, and prominences. Longer exposures will wash out the details closest to the lunar disk but will show more of the coronal streamers and structure.

The brightness of the corona drops quickly as the distance increases from the surface of the sun (just behind the moon). Nearest to the lunar disk the corona is as bright as the full moon and the prominences are laser pointer red dots. Just one lunar diameter away from the disk the brightness is a quarter the intensity and at two or three diameters it is dim as the background sky. Streamers can be seen up to six diameters away with binoculars or a well trained eye.

To obtain a good image of the corona you will need to take multiple images with variable exposure lengths. These images are then stacked and processed later in the computer using a variety of techniques beyond the scope of this article. My recommendation is to start with a shorter exposure and then increase by one setting for another on up to the maximum exposure for the session. Time allowing, repeat the progression in reverse and then wait for third contact before attempting to get a diamond ring shot.

Automated Camera Control

One trick for the advaned eclipse chasers is to wire up your camera(s) to a computer. For more information about creating such an interface visit the following web site: Eclipse-Orchestrator and Umbraphile. These software solutions will control multiple cameras with multiple exposure runs allowing you to sit back and enjoy the show in the sky!