In 1995, with a borrowed telescope and a couple of cameras, Babak Tafreshi traveled to a remote locale halfway across Iran to record an event that lasted a mere 14 seconds. It was a total solar eclipse—the first of 12 he has photographed in a career that has earned him steady work for National Geographic.

"The phenomenon is quite stunning,” says the photojournalist. “The change of the light and the environment is very dramatic." It's not uncommon to see birds hustling back to their nests and mosquitoes springing to life in midday.

Needless to say, you can't help but be deeply moved by the experience. "It happens to everybody," Tafreshi admits, "even those scientists who have seen total eclipses plenty of times."

On August 21, Trafreshi will be here in the U.S. to record the Great American Eclipse, which will be visible across much of the country. By now, he's accustomed to dealing with the dramatic changes in light and the challenges presented by the oh-so-brief window when the moon completely obscures the sun.

If you’re one of the lucky ones in the total eclipse’s path, here’s what you need to know to photograph the event.

Plan Ahead

Tafreshi is planning to record the Great American Eclipse from a spot in Wyoming's Grand Teton National Park, which is located squarely within the 70-mile-wide path of totality that angles across the country from Salem, Ore., to Charleston, S.C.

If you live outside that band, you'll need to plan a roadtrip to catch the total eclipse or settle for simply seeing a partial one.

Either way, think in advance about ideal backdrops for your photo, because you won't have much time for location scouting on the day of the event. At best, totality will last 2 minutes, 40 seconds, depending on your location. Try finding a spot flanked by a mountain range, a lake, a stand of trees, or even a great old barn—anything that will add context and character to the snapshot.

Stay Safe

Your mom was right, it's not good to look directly at the sun.

To view the solar eclipse safely, you'll need specially tinted glasses (often sold in packs of three or more). You can find them in drugstores and, of course, on Amazon, usually for less than $5 a pair. According to NASA, they should be certified to meet the ISO 12312-2 international standard and include the manufacturer's name and address somewhere on the product.

You will also need to invest in a special solar filter designed to block infrared and UV radiation to safeguard your camera. "The intense magnification through a lens creates a concentration of heat and energy similar to burning a leaf with a magnifying glass," says pro photographer Ken Sklute, who co-authors Canon's eclipse blog. "So choosing to photograph without a solar filter can harm your image stabilization and aperture mechanism, damage the sensor and shutter, and cause permanent eye damage.”

Solar filters can be placed or screwed on a camera lens. You can find one online and in retailers that sell photography equipment. They cost roughly $20 to $50.

And, last, even with a filter on the lens, you should not view the solar eclipse through a camera's viewfinder (unless it's an electronic viewfinder like the one on the Sony a7S). Use the device's LCD screen to compose the shot instead.

Most modern cameras from manufacturers such as Canon and Nikon have buttons next to the display or the viewfinder that activate the Live View mode, which lets you safely see what's in the frame by looking at the screen.

The one time when it's okay to remove the solar glasses and the solar filter is during totality, when the moon completely blocks the sunlight. Before attempting to do that, though, make sure you know and understand the stages that lead up to that phase, says Artur Pietruch, who handles the digital camera testing in our labs.

Choose the Right Lens

To capture the majesty of a solar eclipse, you're going to need a superzoom point-and-shoot or, better yet, an interchangeable lens camera, something akin to the modestly priced Canon EOS Rebel T5i or the more advanced Nikon D7200.

If your smartphone camera ranks among the best, it may have an image sensor powerful enough to record the light of a full moon, but it certainly can't zoom in close to the heavenly orb as it blocks the sun. For that, you'll want a telephoto lens.

"Anything above 200mm is usually considered good for eclipse photography," says Tafreshi. "If you're shooting with an automatic camera, anything at 10x optical zoom would be a proper close-up view of the sun."

Sigma makes an 18-300mm lens that sells for only $400. If that's too steep, you can also think about renting a lens for the big show. If you wish to capture a full-frame image of the eclipse, you can pair the lens with a teleconverter as well, which will increase the focal length at the expense of sharpness. One of those can cost anywhere from $200 to $500.

And, last, you'll need a tripod because any slight motion with your hands will be captured in the image when you're shooting with a telephoto lens. If you don't have one handy, try leaning against a tree or a big rock to steady the lens. Pietruch recommends that you use a pan-and-tilt tripod because the sun is not going to stand still while you photograph it.

"When viewed through a big telephoto lens, it will move very fast," he says.

According to Tafreshi, some photographers actually use telescopes in place of zoom lenses, because they're known to produce sharper images. To link the two devices together, you have to invest in a T-adapter for the telescope and a T-ring for the camera (about $10 to $20 each). Just make sure the adapters are compatible with each respective device before ordering them.

Before using a telescope, be sure to heed the safety precautions outlined above: Use a solar filter to protect the camera, and do not look through the telescope using the camera's viewfinder.

Find the Right Exposure Settings

When the big moment arrives, you'll have only a couple of minutes to bag the shot, so take some time beforehand to experiment with exposure settings.

"During an eclipse, there is no bright source for a digital camera to focus on," Tafreshi says. That means you can't really use auto focus. Turn on the manual focus instead, and set it to infinity. Now turn off the camera's flash. It won't help you.

Then, as the sky darkens, test various exposure combinations to find the right balance between aperture and shutter speed, Sklute adds. By doing that before totality, you save yourself from a frantic guessing game during crunch time. It also cuts down on movements that can distort your image, due to the long shutter speeds required to shoot photos in low light.

If you've ever watched a street photographer at work, there's a good chance you've heard the oft-repeated mantra "f/8 and be there." Generally speaking, the f/8 aperture provides your images with enough depth of field to prevent critical focusing mistakes. For a solar eclipse, a setting between f/8 and f/16 is ideal, depending on the shutter speed you've selected.

Relax and Enjoy the Moment

"This one will be the most widely viewed eclipse in human history," Tafreshi says. "It's passing through one of the world's largest countries, with plenty of space, and many people will travel here from other countries."

That means millions of images will appear in its wake, popping up like a galaxy of stars on Facebook, Instagram, Twitter, and Pinterest. Try to keep that in mind when planning your photograph. You don't have to get the perfect shot—just one that makes you smile.

If you're not on assignment for National Geographic, pause to admire the surroundings, Tafreshi says. Snap pictures of your friends and neighbors as they point to the sky. "It's not all about capturing the image," he explains. "Take a minute to enjoy the experience."