With the Great American Eclipse happening in just weeks, many people are looking for ways to record the event on camera. While photographing an eclipse is not as easy as photographing your family, it is not too difficult for the average person to do successfully — with a bit of knowledge and practice beforehand.
The three key ingredients to photographing an eclipse are doing it safely, having the right equipment and using the right camera settings.
Safety is the first key, because no one wants an eclipse watching party that includes permanent eye damage. Just as you would never look directly at the sun on a normal day, you do not want to do it here. You will need eclipse glasses for your eyes and a solar filter for your camera. Eclipse glasses and solar filters are basically the same thing: a coated piece of glass or film that blocks 99.999 percent of the incoming light, and allows just enough light through for your eye or your camera sensor to see the eclipse safely.
Sunglasses are not nearly dark enough for this, and should not be used. You should use a solar filter that is certified to meet the ISO 12312-2 standard, which means that it will reduce not only the visible light, but also incoming ultra-violet and infrared light to safe viewing levels. These filters can be ordered online. Persons with interchangeable lens cameras can buy them in the correct size to screw onto the end of the lens. They also come in plain sheets that can be cut to size.
While you can successfully record the eclipse with virtually any camera, this is a situation in which having a lens with a longer focal length is better. Professionals may be using lenses with focal lengths longer than 1000mm, but most people will do fine with a zoom lens in the 200-300mm range.
For the rest of this article, I am going to assume the reader has an interchangeable lens camera, such as a Canon, Nikon or Sony, or a zoom lens camera where the exposure can be manually set. If your camera attaches to a telescope, you can, of course, use that, but you would need to get the solar filter that fits over the end of the telescope. Finally, you will want to use a tripod. Because you are photographing something that is very far away, any movement or vibrations that affect the camera will cause blur.
Modern cameras have sophisticated computers inside that can help calculate the correct exposure for most situations. Unfortunately, I have found that this situation is not one of those. Using the manual settings on your camera is the best tactic.
Fortunately, because photographing the sun is something that we can do almost every day, there is lots of time between now and the eclipse to practice and determine the correct settings for your camera. If your camera displays a histogram (a graph that shows how many of the pixels in the image are dark or light), now is a great time to learn how to use it. You don’t want to use settings that are going to let in too much or too little light.
The last time that I photographed the sun this summer, I used the following settings along with my solar filter. These are a good place to start, and you can adjust them for your camera while you practice.
Shutter-speed: 1/500 sec. This is comparable to what you would use for sports photography – it only opens the shutter for a split second, reducing the chance of blur from movement or vibration.
Aperture: f/8. The aperture is a diaphragm that acts like the iris of your eye, dilating to let more light in or contracting to let less light in. f/8 is usually in the middle of the range for most cameras, and will allow you room to adjust to let more or less light in as you practice.
ISO 800: People who remember the days of film remember the ISO ratings of different films; film with a higher ISO rating was more sensitive to light. Digital cameras still have an ISO setting, but it now stands for the amount of electronic amplification that the image gets inside the camera. A higher ISO will produce a brighter image, but also more noise!
Focus: Once again, your camera may not be able to automatically focus on the eclipse, so you will have to set it manually. My lenses have a helpful focus mark at infinity, which works well for me. You should experiment beforehand to see exactly how far to turn the focus dial to get the sun in perfect focus.
The settings that you determine should work for the entire event if you are in an area where the moon does not completely cover the sun (totality). If you are in that area, you need to be prepared to take the solar filter off for that time, since you will not need it. You will want to remember to replace it before the sun reappears, though!
The final thing to do is practice. Practice photographing the sun in the weeks leading up to the eclipse. See what settings work for your camera. When the eclipse day comes, you will have everything prepared!
Dr. Louis E. Keiner is an associate professor of chemistry and physics at Coastal Carolina University. He joined the university faculty in 1998 and specializes in physical oceanography, satellite remote sensing, hurricanes and climate change. He also has a passion for photography.