Allentown School District (ASD) Planetarium: Photographing Eclipses

Photographing a
Total Solar Eclipse

Gary A. Becker and Allen Seltzer

P H O T O G R A P H I C   T A B L E S   B Y   A L L E N   S E L T Z E R

Image Size Partial Diamond Ring/Prominences Corona Film


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ABOVE: This ultra wide-angle photo was taken about 20 seconds before the end of totality during the July 11, 1991 solar eclipse off the coast of Kilua-Kona, Hawaii

BELOW: An ultra wide-angle image of the July 11, 1991 eclipse taken about 10 seconds after totality. Inset, reveals the gossamer glow of the corona about three minutes into totality. All photography courtesy of Gary A. Becker.

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A solar eclipse provides the opportunities for a variety of exciting photographic projects that can yield spectacular results without having to remortgage the house to purchase equipment. In fact, almost any camera-lens-film combination will allow you to document some aspect of the event. Thatís how easy it is.

Because the sizes of the sun and the moon in the sky are rather small, some type of telephoto or telescopic lens system is essential for recording the eclipse itself. The angular size of the sun and the moon in the sky are about one-half degree. The size of the image of a particular subject on film is a function of the angular extent of that subject and the focal length of the optical system being used. For a given subject, the greater the focal length of the lens, the larger the image size. The table below summarizes the image size for a standard 35mm film format and various lens combinations.


Lunar Image Size vs. Focal Length of Lens

Focal Length of LensSize of Lunar Image on Film
(mm)(in.)mm(in.)
501.970.460.018
1355.311.240.049
30011.812.750.108
50019.694.590.181
80031.507.340.289
100039.379.180.361
120059.0611.020.464
200078.7418.360.723

To obtain the approximate magnification of your lens, take the focal length of the lens in millimeters divided by 100, multiplied by 2. A 135mm lens will produce a power of about 2.7 (135/100 x 2 = 2.7x). For shipboard photography, lenses with focal lengths greater than 600 mm may prove difficult to manage because the ship will have a variety of oscillatory motions induced by the water in which it is floating.

In order to photograph the partial phases of the eclipse directly, the brilliance of the sun must be greatly reduced, often as much as ten thousand to one million times before reaching the film.. The best and safest way to do this is with a metal-coated glass or Mylar sun filter that fits directly over the objective lens or mirror. This keeps the intense heat out of the optical system altogether. Metal coatings are very effective in not only reflecting away most of the visible light from the sun, but also attenuating the harmful invisible ultraviolet and infrared radiation. Many telescope and optical manufacturers offer such filters which are safe for both photographic and visual observation of the sun.

One drawback to some of the metal-coated filters is that they alter the true color of the sunís image in a way that depends upon the material being used for the coating. Usually, the color is not too objectionable. Chromium coatings render the solar image orange, while aluminum filters add a deep blue cast. Filters using Inconel, the trade name for a nickel-based alloy containing chromium and iron, provide a very pleasing yellow-white image in a very durable coating.

The partial phases of the eclipse can also be photographed without long focal length lenses and without filters by using any one of the projection techniques described earlier. Even simple, nonadjustable cameras can be utilized to record an image of the partially eclipsed sun from a projection screen held behind a binocular or telescope, or the crescent sun images formed on the ground by the spaces between the foliage of a tree. The light meter may be used to gauge the exposure of the projected image for automated cameras. However, if the sun's image occupies a large area of your camera's viewfinder, it may be necessary to increase the metered exposure by one or two stops. The rule of thumb here is that overly bright images, when metered, require more exposure, while lots of dark objects in an image requires you to underexpose the photo to obtain the best results. The best advice is to bracket your exposures to obtain the best photo. Suggestions for exposures are given below:


Exposure Values for the Direct Photography of the Partial Phases of a Solar Eclipse Using an Aluminized Mylar Filter

ISO/ASAf-stopTime (s)
50-64f/5.61/125
f/81/60
f/111/30
100-125f/5.61/250
f/81/125
f/111/60
200-250f/5.61/500
f/81/250
f/111/125
400-500f/81/500
f/111/250
f/161/125

Filtered exposures were taken by Becker with a Bausch and Lomb Micro-line solar filter which produces a very natural yellow color. His base exposures were 1/250s at F/8-5.6 using ISO 64 Kodachrome Professional side film. I bracket by 1/2 stop. These values agree fairly well with the Seltzer settings noted above for aluminized mylar which produces a blue image. It is important to first experiment with your own equipment prior to the big event because of the variations between filter types.

All features of the total phase of the eclipse: the diamond ring effect, the chromosphere, prominences, and corona, are viewed and photographed without filters. Any filter used for the partial phases should be cautiously removed at the onset of the diamond ring. Be careful not to remove the filter too soon. For best results, telephoto or telescopic lenses are required. A sturdy tripod and mount are also imperative for good results.

Begin your program by having your camera set for the diamond ring. This will require a relatively fast shutter speed. As the last bright point of sunlight disappears, the chromosphere and prominences will be visible on the moon's advancing limb. Again, a fast shutter speed will be required. Be certain to center and focus your camera before each picture is taken.

For shipboard photography, the process is a little trickier. The ship will be rolling, pitching, and yawing slowly. These motions will tend to keep the image on the move and allow for less precise centering. When the diamond ring occurs, there will be little time to do anything else but snap the picture. Centering of the image will have to occur later at a photo lab when enlargements are ordered or when the image is copied if slides are the preferred medium.


Exposure Values for Diamond Ring, Chromosphere/Prominences--No Filters

ISO/ASADiamond Ring EffectChromosphere and Prominences
f-stoptime (s)f-stoptime (s)
50-64f/41/2000f/5.61/2000
f/5.61/1000f/81/1000
f/81/500f/111/500
f/111/250f/161/250
f/161/125f/221/125
100-125f/5.61/2000f/81/2000
f/81/1000f/111/1000
f/111/500f/161/500
f/161/250f/221/250
f/221/125f/321/125
200-250f/81/2000f/111/2000
f/111/1000f/161/1000
f/161/500f/221/500
f/221/250f/321/250
f/321/125..
400-500f/111/2000f/161/2000
f/161/1000f/221/1000
f/221/500f/321/500
f/321/250..

On July 11, 1991 Becker photographed the last of the diamond ring and prominences under hazy-clear sky conditions at 1/500s, F/4.5, using ISO 200 Kodachrome Professional slide film. He employed a 500mm, F/4.5 lens. These exposures vary greatly (between a 3.5 to 4.5 stops) from those suggested by Allen Seltzer and were probably the result of the weather conditions, as well as the lower altitude of the sun. Another photo at 1/250s, F/4.5 showed prominences very beautifully

You will next want to turn your attention to the corona. Because of the great dynamic range of brightness of the corona, several photographs will be required to record all of its different features. Short exposures will show the inner most part of the corona, including any prominences which may be projecting outward from the sun, while longer exposures will reveal the fine detail of the outer corona. The simplest means of recording the corona is to go through the entire range of shutter speed selections of your camera beginning with the recommended setting for the chromosphere and prominences given in the preceding paragraph. If time permits, several exposures should be made at each setting to ensure at least one good image. Maximum exposure lengths should be short, in the one half to one second range; if your objective is to obtain a crisp images of the eclipse, and you have a long focal length lens which is not being guided.


Exposure Values for Inner and Outer Corona
No Filters

ISO/ASACorona to .5 Solar RadiusCorona to 2 Solar Radii
f-stoptime (s)f-stoptime (s)
50-64f/5.61/30f/5.61
f/81/15f/82
f/111/8f/114
f/161/4f/1610
f/21/2..
100-125f/5.61/60f/5.61/2
f/81/30f/81
f/111/15f/112
f/161/8f/164
f/221/4f/2210
200-250f/5.61/125f/5.61/4
f/81/60f/81/2
f/111/30f/111
f/161/15f/162
f/221/8f/224
400-500f/81/125f/81/8
f/111/60f/111/4
f/161/30f/161/2
f/221/15f/221
f/321/8f/322

Becker's rule here is to start at 1/125s, F/4.5 and increase exposure values by changing the shutter speed by one stop at a time: 1/60s, 1/30s, 1/15s, 1/8s, and 1/4s. This was using ISO 200 Kodachrome Professional film. In 1991, using this technique, coronal detail was captured to about 1.5 solar radii at 1/4s under hazy-clear sky conditions.

Longer focal length lenses are affected by the Earth's rotation and other motions of an unstable platform very easily. A good rule of thumb for maximum exposure duration is to take the focal length of your lens and divide it into the number 500. It you are using a 135mm lens to capture the eclipse, then simply divide 135 into 500. You can shoot safely for about 4 seconds before the Earth's rotation becomes noticeable. However, this is only the case if you are imaging the eclipse from land. Shipboard photography has less tolerance with respect to exposure lengths. Under relatively calm sea conditions, about one second is the limit. This, however, can be compensated for by using different speed films. Some recommended films for eclipse photography are listed below.


Suggested Films for Photographing a Total Solar Eclipse

Film NameTypeIDISOExposure choices (#)
Kodachrome 64 Prof.slidePKR-366436 only
Kodachrome 200 Prof.slidePKL-3620036 only
Kodak Royal GoldprintRA10024 or 36
RB20024 or 36
RC40024 or 36
Fuji Super G PlusprintCN10012, 24 or 36
CA20012, 24 or 36
CH40012, 24 or 36
CZ80036 only

Fuji films do not saturate colors as well as Kodak Royal Gold films which were developed specifically for this trait. This is particularly noticeable in the reds, which are important in capturing the chromosphere and prominences. Kodak Royal Gold is also a higher contrast film which may cause it to lose some detail in the inner corona, but will probably provide for more vivid outer corona detail. I would personally recommend Kodak products for photographing this eclipse.


If you are going to photograph from a ship and use a relatively long focal length lens (above 135mm), it is mandatory that you watch the image through the viewfinder of your camera at all times. The rocking motions of even a large stable ship will slowly move your image right-left-up-down, and during these intervals attempts to photograph the eclipse will result in disappointment. However, about every five to ten seconds these motions will cancel each other, and the eclipsed sun will hang motionless for up to one second. This is when your exposure must be taken. It will certainly be difficult to remain focused while all of this beauty is happening above and around you, and hundreds of excited people are cheering, clapping, and exalting the majesty of the eclipse. However, if you practice your routine before the eclipse, and keep your project as simple as possible, you will meet with success.

During the July 11, 1991 total solar eclipse on the Independence, 36 miles off the coast of Kailua Kona, there were a myriad of problems which had to be dealt with. Because of its small size and age, the ship was not a very stable platform, so its yawing, pitching, and rolling were easily witnessed in the camera viewfinder at 10x. This was coupled with vibrations from the engines to keep the ship properly oriented, camera shake when the film was advanced, vibratory motions created by the milling of people on deck, and hazy skies which increased exposure lengths. Of course, the Earth continued to rotate, producing yet another motion which had to be compensated for every couple of minutes. But when totality occurred, it seemed as if time stood still: no one moved, the ship's engines were cut, and the wind died. For over two minutes I observed a nearly motionless image, took nearly 20 pictures and got about a 15 second visual peak at the eclipsed sun. During the next minute and a half, I probably only snapped three or four more images because the exposures were of a longer duration.

The question may be asked, with all of the additional problems, why observe from a ship? The answer was obvious to the 35,000 people stranded on the Big Island of Hawaii under a persistent cloud deck that would not budge. There has never been an eclipse cruise that has missed seeing totality. And because of this reason, the problems of shipboard photography become minor against the backdrop of not witnessing the event at all.

In conjunction with all of the beauty surrounding the eclipsed sun, there is more that has to be considered. The changing color and brightness of the sky and landscape can also make for an interesting sequence of photographs. A normal or wide-angle lens is best for this. Determine the exposure at first contact and stick to it throughout the eclipse. Take a picture of the landscape every 10 minutes or so, and you will see the scene darkening as more of the sun is occulted by the moon. The reddened coloration of objects just before totality can be very beautiful to capture also. Allow your tripoded camera to meter normally and follow its suggestions bracketing above and below the suggested values in whole stop increments. Photography during totality of other people engaged in viewing the eclipse could prove interesting also. You will certainly need a tripod, and if you have an automatic camera, you will need some type of covering for your flash to insure that it does not spontaneously fire and ruin the serenity of darkness for everyone else. If your camera has a manual override, use it!

For a successful photographic program, careful planning is essential. Be sure that you have a full roll of film in your camera or cameras before totality begins. Make sure you use a 36 exposure roll of film so that running out of film during totality won't happen It would be an incredible waste of time to have to reload during totality, and besides, the darkness may pose some difficulties in seeing what you are doing. If your camera does malfunction during the eclipse, look up and enjoy. Everyone will be interested in sharing their photos with you.

Make sure the batteries in your camera are fresh and that you are carrying spares with you. Know your equipment. If you are using any new or unfamiliar lenses or cameras, learn how to operate them before the eclipse. It is also a good idea to test your camera prior to the trip. Rehearse your program. Know exactly what you are going to do during those precious few minutes of totality. Practice taking photos on the ship before the eclipse to acclimate yourself to its motions. In case there is a problem, and you need light, make sure your flashlight bulb is covered with red cellophane or nail polish or use an LED lighting device. A cassette tape recorder might be fun to bring along to chronicle your impressions and those of your friends.

To protect your valuable film against possible X-ray damage from airport security inspection, use the specially designed lead foil bags available at most camera shops to store your film, or ask that your film be hand inspected. I have personally had no problem getting my film hand inspected at Lehigh Valley International Airport, but in other locations where the compression of people is greater or security is tighter, I have been refused and made to use the X-ray machines. The type of film that you will be using probably won't need any special protection unless its ISO rating is 1000 or greater. However, every time I see my lead foil bags disappear behind the curtain, I breathe a small sigh of relief knowing that I have done all that I can to protect the most personal and valuable souvenirs of my trip.

Finally, if you are planning a photographic project, by all means take some time to look at the eclipse visually or through binoculars. So much will be missed if you spend all of your time watching the eclipse through the viewfinder of your camera. I know; I've made that mistake and many others too!


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