Photographing Solar Eclipses

Photographing Solar Eclipses

This page is still under construction. Please check back later for additions and improvements!

This page contains sections about what to photograph, solar filters that are necessary during partial phases of the eclipse, lens choice, camera mounting, and exposure, as well as other equipment and how to set your camera. Finally, there are some practical suggestions about focusing, aiming your camera, and how to make and practice a plan for your eclipse photography project.

Although it predates the digital photography era, this page by Fred Espenak contains a lot of useful information and links regarding solar eclipse photography.

What to photograph

Without doubt, the most familiar kind of photograph of a solar eclipse is a telescopic image such as those on my eclipse photography page, but solar eclipses offer many other photographic opportunities too. Close-up images of the eclipsed sun require long telephoto lenses, but many other subjects can be captured with ordinary camera equipment.

Instead of being isolated in a photograph, the eclipsed sun can be incorporated as one element of a landscape that incorporates other objects silhouetted against the darkened sky. Another project that produces interesting images is to take multiple exposures of the progress of the eclipse, for example at intervals of five minutes, showing the sun's motion across the sky as the eclipse progresses. Examples of both types can be found in Fred Espenak's page. Either of these kinds of projects requires carefully checking the expected position of the sun in the sky during the eclipse, so the camera can be positioned where the sun and other objects will be arranged as intended in the photograph.

Other phenomena that occur during eclipses can be photographically interesting. As totality nears, the quality of the sun's light becomes quite eerie because the shape of the sun's bright region changes from the usual circle to a crescent-like and ultimately a slit-like shape. Shadows become unnaturally sharp-edged, and the little spots of sunlight that form the usual dappled appearance under a tree all become crescent-shaped instead of round. Various creative things can be done with these shadows.

As the moon's shadow races toward your position, you may see a wedge of darkness in the western sky and clouds on the western horizon going dark before totality actually begins at your position. As totality arrives, a wide-angle shot may show the moon's cone-shaped shadow extending down toward the earth. After totality arrives, it is common to see a pink sunset-like glow on the horizon in all directions. These phenomena can add interest to photographs.

Finally, it is fun to watch your fellow observers, with all their interesting ways of experiencing the eclipse. Here are some images taken at past eclipses by my wife, Louise Halstead.

Above images Copyright (c) Louise Halstead, 2009-2012.

Don't forget to look!

When totality lasts just a couple of minutes, it is easy to get so wrapped up in projects that totality is over before you have really taken time to just experience the eclipse with your own five senses. This would be a terrible shame, because your eyes and your other senses can show you the eclipse in ways that no photograph or video can reproduce.

You really owe it to yourself to plan your activities so you will be able to just look at the eclipse for a minute or two, admire the glow of the corona and its streamers, look for stars and planets in the darkened sky, and notice the effect of the eclipse on the natural world and the people around you. If you've planned and rehearsed your photography project in advance, you will be more able to experience the eclipse even while you go through your planned routine. This is a great goal to strive for.

If you have brought binoculars or a small telescope with you, by all means use them to look at the totally eclipsed sun. The coronal streamers, prominences, and just the glow of the corona right around the sun will amaze you. Don't forget to look!!

Solar filters

During partial phases of the eclipse, the brightness of the visible part of the sun, even if it is very small, is so intense that it can damage your equipment and permanently damage or destroy your vision. To safely view or photograph the eclipse at any time other than totality, you have to use a special solar filter to block most of the sun's light before it reaches your eyes or your equipment.

The only exception to this rule is during the few seconds when Baily's beads or the diamond ring are visible. At these times, the visible portion of the sun is so tiny, and only remains visible for a few seconds, that it can safely be viewed and photographed without a filter. Indeed, the only way to actually see the "diamond ring" effect is without a filter, because with the solar filter you won't see the corona at all.

The standard filters for solar viewing and photography absorb or reflect 99.999% of the light that falls on them, passing through just 1/100,000 of the sun's light. Not all materials that appear to darken the sun enough for comfortable viewing actually stop all harmful rays, such as infrared radiation, so it is very important to choose a safe filter. Advice about safe techniques and filters for solar viewing is found in various places, such as this article from Sky and Telescope magazine. Please check this information and take it to heart!

Many of the photographs of the partially eclipsed sun on this page and my companion solar eclipse page were taken using a glass solar filter made by Thousand Oaks Optical. These filters are custom-made for the size of the front of your lens or telescope and cost $70 and up, depending on the size. The filter fits over the front of your lens by a friction fit; it does not screw on like a regular camera filter does. These filters give the sun a yellow-orange color cast that is fairly pleasing, though of course it can be changed as desired in postprocessing.

The glass filters use a shiny layer of aluminum that is evaporated onto a glass plate. I have found that when using this type of filter with a digital camera, it is important to tilt the filter a bit because some of the light falling on your camera's sensor will reflect off of it, up toward the back side of the glass filter. If you put the filter on exactly perpendicular to the viewing direction, the filter will then reflect this light back down toward your sensor again, creating a ghost image. By tilting the filter a bit relative to the light path, you can deflect this ghost image so it does not fall on your imaging sensor.

There are also various filter materials that are manufactured as flexible films. High reviews have been given to the Baader AstroSolar film. The material is sold in small sheets that you can cut with scissors and mount into a home-brew mount to cover your camera lens, binoculars, or whatever. Advice for making home-brew mounts is available on the vendor's Web site.

Lens choice and image size

The sun is a small object in the sky, and if your goal is to make a close-up image of an eclipse, you'll need to use a telephoto lens. The following are "straight out of the camera" images taken using a Canon APS-C camera body (which has a "crop factor" of 1.6) with a 300mm lens and a 600mm lens. The equivalent focal lengths for a "full-frame" camera using a standard 35mm sensor are 480mm and 960mm, respectively.


300mm lens on APS-C camera (35mm equivalent focal length 480mm)
Image taken using a Mylar film filter


600mm lens on APS-C camera (35mm equivalent focal length 960mm)
Image taken using a Thousand Oaks glass filter

Obviously 300mm is pretty much a bare minimum focal length for a close-up view of an eclipsed sun. Of course, if your project is a scenic image of which the eclipsed sun is just one element, then you can choose a focal length that is appropriate for your scene. If you are interested in photographing effects such as the moon's oncoming shadow or the sunset color all around the horizon, you may want a very wide-angle lens.

Generally, if you want to know how big the sun will look using your combination of camera and lens, you just need to take your equipment out on the night of a full moon and take a picture of the moon. It is the moon that covers the sun, so the size of the moon in your image will be the same as the size of the dark circle of the eclipsed sun.

Camera mount

For photography with a long telephoto lens, a solid tripod is a must. Equally important is a "cable release" or remote control for the shutter, to avoid degrading the image with vibrations from pushing the shutter button.

Although we often aren't too aware of it, the sun moves across the sky remarkably fast because of the earth's rotation. In two minutes, the sun will move by a distance equal to its own diameter. This means that if a camera with a long telephoto lens is mounted on a fixed tripod, the sun will only take a few minutes to drift completely out of the field of view. Tracking mounts are available with drive motors in them that move the camera at exactly the right rate to track the motion of the sun across the sky. In the busy moments near and during totality, it is a real lifesaver to know that the sun will remain centered in your camera's field of view without continually having to re-aim the camera.

In the past, I have used a tracking mount designed for telescopes, with a camera adaptor. The following image shows me using the mount. The mount that I used is heavy and bulky for travel, however, so I'm thinking that for the next eclipse I may try using the iOptron SkyTracker. Sky and Telescope magazine has published a nice review of this item.


My son and I, with our eclipse photography and viewing setup.
I am in the foreground, with my tracking mount, camera with 600mm lens,
Thousand Oaks solar filter, and improvised counterweight.
China, July 22, 2009

Using the SkyTracker or any tracking mount requires some sophistication about how to align the mount with the earth's axis. You will need to do this during daytime, when you can't see the North Star. Giving instructions on this topic is, unfortunately, beyond the scope of this little overview page.

Exposure

There is an immense range of brightnesses in a solar eclipse. Even during totality, the range from the brightest to the faintest features spans at least 12 photographic stops (a factor of 4000). One benefit of this fact is that almost any exposure of a totally eclipsed sun will show you something interesting! As a guide for what results to expect from various different exposures, the following collection of images is "straight out of the camera" as far as exposure is concerned, though the images have been cropped to make it easier to see the details of interest. Clicking on any of the images will get you a larger version to examine.

Partial phases

During partial phases of an eclipse, a solar filter must be used. The following images were taken using a Thousand Oaks glass filter. You can (and should!) compare these results with what your own equipment gives you by taking some test shots of the uneclipsed sun during the months before the eclipse.

For the uneclipsed sun, or partial phases where much of the sun is still visible, an exposure equivalent to ISO 100, f/11, and 1/60 second works pretty well, as shown in the following images.

In these images, it can be seen that the brightness at the edge of the sun is not quite as great as the brightness in the center. For this reason, as totality approaches and only a small region of sun close to the edge is still visible, you may want to increase your exposure a bit. The following image was taken at 1/15 second instead of 1/60 second.

The edge of totality

To capture Baily's beads and the diamond ring, the solar filter has to come off; otherwise no details of the corona will be seen. The following images show the details that can be captured at different exposures with the filter off. These images are all from the beginning of totality at the March 2006 eclipse in Egypt. They are shown in chronological order, so you can see the "diamond" of the diamond ring progressively disappearing during the sequence. You can also compare the images to see how the exposure affects the capture of coronal details and of the impressive prominence located near the 12 o'clock position.

Here are some images of the diamond ring at the end of totality of the same eclipse, to give a few more examples of different exposures.

Mid-totality

In mid-totality, the moon covers the chromosphere and most prominences, and the main items of interest are the feathery details of the corona. The inner corona is quite bright, but the outer streamers are much fainter, so a wide range of exposures can be used. These images show the results of using various different exposures.

These images were taken in midday under a very clear desert sky in Egypt. Under less favorable conditions, exposures may need to be adjusted. One way to gauge the conditions is to check the brightness of the sun in pictures of the partial phases that are taken before totality. If you find that the best exposure for the partial phases is two stops more than your best exposures of the sun taken under clear skies before traveling to the eclipse, then it will be wise to increase your planned exposures during totality by two stops also.

Camera settings and equipment

Here is a collection of suggestions for camera settings and auxiliary equipment, based on my experiences.

  • Use mirror lockup as well as a cable release or remote control to minimize vibrations for telephoto shots. On most DSLR cameras, when the mirror lockup mode is enabled, the first click of the shutter button locks up the mirror, and a second click of the shutter actually takes the picture. You probably want to wait a short time for vibrations to die down (a half second or more) between locking up the mirror and taking the picture. On the other hand, at times like the diamond ring, the phenomenon only lasts a couple of seconds, so you can't wait too long. It is a good idea to experiment beforehand, taking pictures of the full moon using your setup, to judge how much time you need for vibrations to die down so you can get sharp images. Even better, if your camera supports it, is to use the live view mode, which means that the mirror is permanently locked up and you only need to click the shutter half as many times.
  • If your lens or camera has an image stabilization feature, turn it off (as you always should when using your camera on a tripod).
  • Use auto exposure bracketing so you can get various different exposures without having to fumble with the camera controls. This saves time, as well as avoiding opportunities for error and avoiding the vibrations that come from touching the camera. The bracketing will automatically give you different shutter speeds in each of three consecutive images. In the past, I set the bracketing to +2/-2 stops, which was the maximum allowed by my camera at that time. I might even consider using +3/-3 stops. After a few shots, you can change the base exposure up or down so you can get some new exposure times between or beyond the exposures in your initial bracketing group.
  • Use raw files. They will give you a lot more latitude to extract details during postprocessing.
  • For white balance, I have used 3600 K for the partial phases (with a glass filter that gives the sun a yellow/orange color) and 5450 K for the unfiltered shots of totality and the diamond ring. These values should provide a reasonable starting point (though you should adjust the white balance for filtered shots if you use a different filter material). A big advantage of using raw files is that it is easy to change the white balance in postprocessing, so you can just take all your pictures using Daylight white balance and then adjust later, at which point you will probably want to adjust the green/magenta tint adjustment also, to taste. You don't want to be trying to adjust the camera's white balance setting just as the diamond ring is appearing!
  • Use a reasonably low ISO speed, in the range of 100-400. Eclipses are actually quite a bright phenomenon, so there's no need to use a really high ISO speed. It is better to benefit from the lower noise and higher dynamic range that come with using a low ISO speed.
  • Eclipses are often high up in the sky, and with the camera pointed up that high, it can be awkward to look through the viewfinder or see the camera's back panel to check settings. It is really helpful to have a 90-degree finder accessory (for example, this one for Canon cameras). If your camera has a live-view mode and the back panel can tilt upward, that may also serve.
  • Similarly, for checking settings on the back panel, unless the camera's back panel tilts upward, it will be really handy to have a small mirror that you can use to look at the back panel without having to crawl down underneath the camera.
  • Finally, you will want to have a small flashlight to use for checking settings, equipment, etc. Even in totality the darkness is not pitch-black: typically, it is only about as dark as the "blue hour" about 30-45 minutes after sunset, so you may not need the flashlight, but you would feel silly if you needed a flashlight and didn't have one. Flashlights that use a red LED rather than a white light are strongly recommended because they will not spoil your eyes' dark adaptation.

Focusing

For telephoto use, the infinity mark on your lens can't be trusted to be the exactly correct focusing point. It really is best to set the camera to manual focus and then focus manually with the lens wide open. Then I like to close down the aperture by one stop to provide a small margin of error. Fiddling with the focus is the last thing that you want to do during totality, so I recommend focusing on the sun with the solar filter in place. You can focus to maximize how defined the sunspots are, or if no sunspots are visible, try to maximize the sharpness of the moon's limb during the partial phase of the eclipse.

If you use a 90-degree finder that has a magnifier, that can be a big help. Most new DSLR cameras have a live-view focusing capability that is even better than that, and it should definitely be used, at maximum magnification, if available.

It is not hard to bump the focus adjustment by accident after you have set it (for example, when removing you solar filter just before totality), so be extra careful! There are few disappointments bigger than discovering that all your images of totality are just a little bit out of focus.

Aiming the camera

Aiming a camera with a telephoto lens at the sun can be surprisingly hard because you have to do it with the solar filter on, and if your aim is off even by a little bit, all you see in the viewfinder is blackness, giving no clue which way to move the camera. The best trick here is to stand to the side of the camera and look at the shadow that is cast by your lens onto the camera body. When that shadow is the smallest, you are aiming at the sun. This technique should at least get you close enough to see part of the sun in the viewfinder, after which you can refine your aim in the usual way.

As with focusing adjustments, the aim of your camera can easily be disrupted if it is bumped by you or by one of your eclipse-watching colleagues. There is no sure way to protect against this, but it's good to be vigilant.

Conditions to expect

A good overview of the conditions and experiences to expect in a total eclipse can be found in Bernie Volz's PowerPoint presentation which was created in preparation for the November 2012 eclipse in Australia.

Practice, practice, practice

The awesomeness and fleeting nature of the total eclipse spectacle make it easy to get flustered trying to do any photographic project. You only have a couple of minutes to get it right, and there is no second chance. The best way to succeed is to make a detailed plan in advance, and practice it before eclipse day with your full setup until you are fluent with all the adjustments required and you know from your dry runs that your plan can be executed within the time available.

Here are some thoughts, based on experience, about elements of the plan. Obviously your plan will differ from this if your focus is on landscape shots or eclipse phenomena other than the eclipsed sun itself.

  • At the beginning of the eclipse, make sure you have a full battery charge in your camera and your memory card has enough space for the images you will take.
  • About 5-10 minutes before totality, check everything again, especially your focus. If the conditions are hazy, compare your exposures of the partly eclipsed sun with earlier images that you took under good conditions, to decide whether you will need to increase your exposure during totality, and if so, by how much.
  • If you plan to try to capture the diamond ring and prominences, about one minute before totality you should get your camera settings ready for these events. You can use the sample images above as a guide for the exposures that you will want to use. Using auto exposure bracketing is highly recommended here.
  • About 15 seconds before totality, as the sun shrinks to a tiny slit of light, it is time to take off your solar filter and be ready for the diamond ring.
  • After you have taken your exposures of the diamond ring and chromosphere, you can reset your exposure as you will want it for recording the sun's corona, and start taking those images. You can use the sample images above as a guide for exposure. Again, auto exposure bracketing is highly recommended. It is good to repeat each sequence of shots a couple of times, just in case the wind or some other factor makes some of them less than sharp.
  • As the end of totality approaches, you can set your camera back to the settings you want to use for the diamond ring and prominences. You may want to use a setting that is one stop more or less than you used at the beginning of totality, just to get a bit more variety.

Your plan for photographing partial phases of the eclipse should be practiced at home on a sunny day. Ideally you can practice it at a time of day similar to when the eclipse will actually occur, so your camera will be aiming up at a similar angle. You can practice setting up your equipment, aiming and focusing your camera, and you can take various test exposures through your solar filter to see which exposure is best.

Your plan for totality is best practiced under a full moon. Again, ideally the moon will be at a similar altitude to the eclipsed sun that you want to photograph. It is a good idea to set a timer and go through your entire plan from about one minute before totality so you will be familiar with all the camera adjustments you're planning to make (and you can make those adjustments in the dark), and it's good to verify that you can follow your plan while still having some time free to experience the eclipse first-hand.

If you have practiced your plan in advance, you should be able to look at and enjoy the eclipse most of the time, even while you click the shutter release to take your pictures. Try to see how far from the sun you can trace the coronal streamers, and look to see whether you can find any planets or bright stars shining in the sky. It is also highly recommended to take a break from your photography long enough to look at the totally eclipsed sun through binoculars.

Finally, try to keep your photography project in perspective. If you have taken the time to experience the eclipse first-hand, then even if your project doesn't succeed as you had hoped, you will still have enjoyed an amazing spectacle of nature.

Postprocessing

(To be written.)

What to do with your images

(To be written.)