The advancing Moon takes a bite out of the Sun in this image taken early during the partial solar eclipse of May 10, 1994. Sky & Telescope's Rick Fienberg captured this view from Ogunquit, Maine, using an 8-inch f/10 Schmidt-Cassegrain telescope and a metal-on-glass solar filter.
Here are several simple tips that will help you succeed at capturing a partial solar eclipse on film:
To show the Sun's disk reasonably large, you need a lens or telescope with a focal length between 500 and 2,000 millimeters. This means you also need a firm tripod or mounting.
Use a visually safe solar filter over the front of the camera lens or telescope. (Check the article "Solar Filter Safety" for details.) Special solar photographic filters, designed to pass more of the Sun's light than visual solar filters, are okay only if used with caution.
Do a dry run on the uneclipsed Sun at least a couple of weeks beforehand. Begin by letting the camera's light meter choose the exposure. Then try a variety of other exposures on either side of it. Keep notes and see which comes out best.
If you're near the path of totality, the Sun will become very thin. When this happens, increase the exposure both for esthetic effect and to compensate for the fact that the Sun's surface brightness is less near its limb.
If the Sun nearly fills the frame, focus to make the solar limb look sharp where it will actually fall on the film, near the frame's edges; don't move it to the center to focus on. Schmidt-Cassegrain telescopes in particular suffer from field curvature that makes the edge focus slightly differently than the center.
To reduce vibration, work the shutter button with a long cable release, or use the camera's delay timer. Lock the viewfinder mirror up beforehand if possible.
Don't forget to take a picture of the uneclipsed Sun at the start of your series to dramatize the change when the eclipse begins.