I have been getting a lot of questions about what focal length lens to use when photographing the upcoming solar eclipse. Like anything else in photography there really isn't one correct answer, it all depends on the image you want to capture. But in order to help you figure that out I decided to shoot a little comparison test, and make the images available here.
First off, the most important thing is to NEVER look directly at the sun without proper solar filtration, and never point your camera at the sun with proper solar filtration. DO NOT use an internal filter in any lens that uses that type of filter, you will destroy your lens. A proper solar filter is equal to approximately 15 stops of neutral density and blocks the infrared and ultra-violet as well. I use Thousand Oaks Optical Solar Filters. They also sell eclipse viewing filters.
There are several things that happen during a solar eclipse, so one of the first things you need to do when planning your shoot is to decide what is most important thing you want to capture. You will hear terms like "first, second, third, fourth contact, and totality" these are used to describe specific events during the eclipse; a bit of celestial mechanics short hand. First contact is when the moon first starts to move in front of the sun - the beginning of the eclipse. Fourth contact is the moment when the moon breaks contact with the sun - end of the eclipse. Second contact is the instant when the moon fully covers the sun and totality begins. Third contact is when the sun's disk becomes visible again as totality ends. For more information on the phases and mechanics of solar eclipses, check out Astronomy Magazine's Solar Eclipse Glossary.
The images below are labeled with the lens length used for the photograph. The angular field of view, in degrees, of the image is included in parentheses. For reference, the size of the sun when viewed from earth is approximately 32 arc minutes (average), or just over half a degree (there are 60 arc minutes in one degree).
If you want to image just the solar disk being eaten by the moon, I call this the "Pac Man" shot, then you may want to use a longer lens. If you are interested in getting the solar atmosphere, called the corona, then you may want to use a medium to short telephoto lens, as the corona extends far out into space.
How To Photograph The Solar Eclipse by Alan Dyer is a wonderful eBook available in the iBooks Store. It is a great resource for all things related to solar eclipse photography. If you are really serious about shooting this amazing event, it is well worth the price.
Camera and exposure information for the following images:
Canon 1DX Mark II - 20 megapixel, full frame sensor, if you are using a crop sensor camera you can approximate the focal length by multiplying the lens length of these images by your crop factor.
ISO 400, f/11, 1/200th second
These images are jpgs directly out of the camera, no cropping.
70mm (28.84H x 19.46V)
100mm (20.41H x 13.69V)
135mm (15.19H x 10.16V)
200mm (10.29H x 6.97V)
300mm (6.87H x 4.58V)
400mm (5.15H x 3.44V)
560mm (3.68H x 2.46V)
600mm (3.44H x 2.29V)
800mm (2.58H x 1.72V)
1,120mm (1.84H x 1.24V)
1,600mm (1.29H x 0.86V)
Hope this helps you in your lens choices. Remember during the eclipse to take the time to look around, and enjoy this amazing natural phenomenon!
Good luck shooting the eclipse! I will be happy to try to answer any questions you may have, just put them in the comments section below. I look forward to hearing from you, I also look forward to seeing your images!
Till then keep shooting!
James
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James Neihouse is a professional cinematographer/photographer. A graduate of Brooks Institute of Photography, he has spent his entire career traveling the world capturing breath-taking images for IMAX films such as Ocean Oasis, Hubble 3D, Blue Planet, Destiny in Space, and his latest film A Beautiful Planet. He is a member of the American Society of Cinematographers and the Academy of Motion Picture Arts and Sciences.
Follow James on Twitter and Instagram - @70mmDP