Photographing the 2017 Total Solar Eclipse

This article covers my experience and what I learned photographing the 2017 Total Solar Eclipse from Casper, WY using DSLR cameras. If you plan to do any solar eclipse photography, including partial and annular solar eclipses,  this article should provide a good starting point with links to various references.

I planned to observe the eclipse in Casper, Wyoming. I went up 5 days early for the Astronomical League convention (where I was a vendor with AstroBox). The long term forecast was sketchy, and kept alternating between mostly clear and partly cloudy. Sunday morning, the day before the eclipse, the forecast looked good enough to plan to stay in Casper, and I took the morning to scout out a location.

AstroCon had worked out an agreement with Casper College, and did a signup sheet for one of 20 reserved spaces on one of the parking lots on campus. I got on the signup list the first day of the convention, and found a nice spot to stake out Sunday morning. I setup all my equipment and basically did a dry run for the eclipse, testing exposure time for the partial phases, and noting where the sun would be from beginning to end.

It so happened I setup next to Fred Espenak, Mr. Eclipse, who has some fantastic resources on his site for eclipse photography that I found very valuable. I got to see his rather impressive camera setup, and I’ll write a seperate article on my whole eclipes experience later.

My Equipment

Now is probably a good time to summarize the equipment I used before diving into details.

Setup SV80/7DII 70-200/T6s
Camera Canon 7D Mark II Canon T6s (760D)
Lens Stellarvue SV80 f/6 APO Telescope
with 0.8x field flattener/reducer
Canon 70-200mm F/4 L
Focal Length 384mm @ f/4.8 200mm @ f/8
ISO 100 100
Solar Filter 4.1″ ID Orion Full Aperture Solar Filter ($80) Rainbow Symphony Solar Filter 101mm Black Polymer ($20)
Controller Intervalometer Intervalometer
Exposure During Partial 1/2000 1/50
Exposure During Total  1/1000 – 4 sec  1/15-1/4-1 sec
Mount Celestron CG-5 EQ
computerized tracking mount
iOptron SkyTracker
motorized tracking mount

Finding the Right Settings

The day before the eclipse, I still didn’t know the right exposure settings to use for totality with my camera and telescope. I spent the evening doing research on this. I had two cameras I planned to use, a Canon 7D Mark II, and a Canon T6s. I’d spent some time researching this in the weeks prior, including looking into software to control a camera during the eclipse to optimize the exposures. By the time I’d left for Casper, I’d already decided to ditch that idea – too complicated, too much to go wrong.

I’d decided to use exposure bracketing, and discovered the Custom Mode settings on the Canon 7DII (C1, C2, C3). These store complete camera configurations, so I was able to program each with an exposure bracketing range to use during totality, from 1/1000 – 2 seconds, up to 1/250 – 15 seconds. Each sequence was a series of 7 exposures. As it turned out, even at ISO 100, 2 seconds was about the longest exposure necessary to capture the corona with the 80mm Stellarvue APO and 0.8x reducer/flattener. This gave me a focal length of 384mm with an f/4.8 ratio. For the partial phases, I also setup a 3 frame bracket just one stop up and down (1/2000 – 1/500). As it turned out, the shortest exposure – 1/2000 was what came out the best in terms of capturing the sunspot details without washing out the disk.

Exposure Time for Solar Images

Many people think that the exposure should get longer as the sun gets covered, but that isn’t the case. There is less light overall, but at a constant focal length and f-ratio, the amount of light hitting a given pixel of the exposed sun (using a white light solar filter, of course) is the same regardless of a full solar disk or a tiny crescent. The lesson for the partial phases of the eclipse is, do a test with your setup of the sun on a clear day, and find the right exposure for the full disk – it will be the same for all of the partial phases of the eclipse, and will likely be a very short exposure. I saw a lot of people testing eclipse photography (using a proper solar filter) selecting very long exposure times, and getting completely blown out images. With a solar filter blocking at least 99.9% of the light, the tendency is to do a longer exposure, but the reality is there is still plenty of light coming through for very short exposures to be all you need.

Partial phases of the eclipse with a constant 1/2000 exposure setting.

 

Imaging totality is harder to judge. Each total solar eclipse is different in terms of the brightness of the corona, sky brightness, and other factors. (The sky was not as dark as I expected during totality.) Exposure bracketing is the solution for totality, and the moments leading into and out of totality. The specific range will depend on your equipment. Use the table by Fred Espenak as a guide.

For my Stellarvue setup, here are the results of the images in the bracket from 1/1000 – 4 seconds. As you can see, the 4 second exposure is pretty much completely washed out. Even the 1 second exposure is mostly blown out. The 1/1000 exposure actually shows good detail on the prominences, and the other exposures between capture various aspects of the corona. The ideal range would have been closer to 1/1000 – 1/4 sec.

A few things to remember:

  • You can take off the solar filter about 20 seconds before full totality. This will let you capture Baily’s beads and the diamond ring. (Accurate timing is important. Take the filter off too early, and you risk damage to your camera.)
  • Put the filter back on no more than 20 seconds after totality ends. Don’t burn your camera!
  • I would suggest a shorter bracketing range (1/2 stop apart) as totality begins. Events like Baily’s Beads and the Diamond Ring happen very rapidly; too long an exposure, you will get washed out images and miss these events.
  • Switch to a wider bracketing range during full totality.
  • Switch back to the shorter bracketing range near the end of totality. (I didn’t do this, and wound up missing the diamond ring and Baily’s beads on the way out as the camera was taking a longer exposure that was just washed out.)

Exact times and ranges mentioned here will vary greatly based on your equipment. This is only a guide based on my experience with my equipment.

The solar prominences visible near the end of totality. 1/2000 exposure with the SV80/7DII setup.

What’s the best camera to use?

The discussion here centers on DSLR or Mirror-less interchangeable lens cameras. Use of CCDs, compact cameras, or phone cameras is not discussed.

Let’s for a moment ignore the Nikon vs Canon debates. One of the big challenges with astrophotography, and Eclipses in particular, is having a wide dynamic range, and preventing pixel saturation and blooming. Essentially, when you are photographing a very bright object at the same time as a very dim object, the bright object will tend to saturate the sensor, and wash out the dim object.

Think of photographing a bare lightbulb right next to an object hidden in a shadowbox so that the light doesn’t get into the shadow box. If you take a very short exposure, you’ll get a crisp image of the lightbulb, and very little detail in the shadow box. If you take a longer exposure, the lightbulb will just be a bloom of light, and while you will get a bit more detail in the shadowbox, the high brightness of the lighbulb may wash it out. What that means is, we want to have a wide dynamic range for capturing the bright corona and prominences near the limb of the Moon, AND the dimmer corona extending away from the Sun, and the stars hidden in the same field of view. No camera will let you take a single exposure to cover the entire dynamic range, it’s just too wide. This is where exposure bracketing and HDR stacking come into play.

Exposure Bracketing

So what is the best camera? For eclipse photography, it would be a camera with exposure bracketing (at least 5 exposures would be desirable) and a high dynamic range. Exposure bracketing is considered a more advanced camera feature. For instance, my Canon 7DII allows bracketing with 3, 5, or 7 exposures, up to 2 stops apart. The T6s, which Canon considers a consumer camera, only supports bracketing with 3 exposures. The hardware of both cameras easily supports wider bracketing ranges, but Canon chooses to limit this in the firmware.

Sony cameras are also limited to 3 or 5 image exposure bracketing; oddly, the limit drops to just 3 exposures as you widen the bracket range to 2 stops between exposures. I’ll note that even the high end Sony cameras like the a7 have the same range and limitations.

Nikon cameras like the D7200 can do up to 9 exposure bracketing up to 1 stop apart, and 5 exposures up to 3 stops apart. Of the three manufacturers, this gives Nikon the widest range and greatest flexibility.

From the perspective of bracketing flexibility, Nikon is the winner here. If you look at DXOMark and the dynamic range scores for various cameras, Sony and Nikon beat out Canon by a full stop of dynamic range. With all that said, I’m not surprised to learn that Fred Espenak uses Nikon cameras.

Does this mean you can’t use Canon and Sony cameras? No, it does not. I used two Canon cameras, a 7D Mark II, and a T6s to photograph the 2017 eclipse. The Canon cameras definitely work for eclipse photography, based on my own experience. The key is understanding and making the best use of the exposure bracketing feature in your camera. If your camera has custom setting modes (User Defined settings in Nikon speak) you can make good use of these to setup camera configurations that will let you extend your range of exposures. But, and here is the but, the consumer grade Canon cameras don’t offer Custom Modes, or more than 3 exposures with bracketing. That makes them a poor choice for eclipse photography (or other HDR photography). Sony and Nikon both offer Custom Modes on a wider range of consumer cameras. (Consumer cameras in this instance are broadly defined as under $800 in price.)

Custom Mode Support

If your camera has Custom Modes, or User Modes (may be called other things) learn how to use these. Custom modes will appear on the mode dial on the top of the camera. For Canon cameras, these are labeled C1, C2, C3. Nikon labels them U1, U2, U3, and Sony just numbers them 1, 2, 3. This is another area where Canon in particular considers Custom Modes an advanced camera feature; the T6s doesn’t have this capability. Strike 2 for the T6s.

The Mode dial on the Canon 7D Mark II showing the Custom modes (C1, C2, C3)

Should I get a new Camera?

In short, no. Unless a new DSLR was already on your wish list for other reasons, an Eclipse isn’t the excuse to get a new one. You want to be very familiar with how your camera functions before attempting eclipse photography, so ordering a new camera a week or two before hand is not a good plan. If you get a new camera, make sure you have time to really familiarize yourself with it before relying on it for any major event.

Eclipse photography is probably a one-time event for most people with a given camera. Even between the 2017 and 2024 eclipses, I expect I’ll have different cameras for 2024. (Now, if someone wants to sponsor a trip down to Chile for 2019 or 2020 total solar eclipses, I’ll use whatever cameras the sponsor wants to provide. Hint to any manufacturer that wants a new astrophotography brand ambassador!)

Most of you won’t be buying a camera with eclipse photography in mind, so really the suggestion here is learn about the capabilities of your camera, and use them to best effect. Learning to use the two key capabilities discussed here, Exposure Bracketing and Custom Modes will serve you well. If you happen to be interested in HDR photography, it so happens that cameras that are good choices for HDR are also good choices for eclipse photography, but the camera you have will always work, just maybe without all the capabilities you would like. To make the most of what you have, get a white light solar filter for your lens or telescope, and practice with the Sun on a clear day.

Do I Need A Solar Filter?

Yes, you do need a solar filter. They aren’t expensive, and you can use them over and over. DO NOT try to use simple neutral density filters! Many of these will not block the IR and UV light that can also damage your camera. Most short of a 10,000 ND filter also won’t block enough visible light. Don’t play games stacking filters – it is far better, and cheaper, to just purchase a good solar filter! The bottom line is, get a known good solar filter, not an ND filter. The price is about the same, and the solar filter will block the IR and UV light in addition to the visible light.

For reference, I paid about $80 for my Orion Glass solar filter on the left, and just $20 for the Rainbow Symphony solar filter on the right. Both are the same size, and I can use them interchangeably between my 80mm scope and my 70-200mm f/4 lens. Both filters produce sharp images, but I prefer the color of the images through the Orion filter.

One note about the glass filters, is they are highly reflective (as you can see in the picture) on both sides of the filter. To avoid a ghost image of the sun in your telescope from this reflection, you want to tilt the filter just slightly (by about 1°) when mounting it. This directs the reflection to the side of the telescope tube and away from the image sensor on the camera.

What happens if you try to photograph the sun without a solar filter? Burned sensors, lens apertures, and if you happen to try to look through the viewfinder, maybe a burned retina. Any time you point a camera at the sun, it should have a solar filter on it. The obvious exception is sunrise and sunset. In those cases, you have several times more atmosphere filtering the sunlight. This allows you to look at a sunset without it being too bright, which is a good indicator of whether you need a solar filter.

Lenses and Telescopes

I used two setups to photograph this eclipse, one a Stellarvue 80mm f/6 telescope with reducer (for a 384mm focal length) on the Canon 7DII, and a Canon 70-200mm F/4 L lens on the Canon T6s @ 200mm and F/8. Pretty much all the images I’ve processed came off the 7DII. I found that focal length was a good balance of capturing details of sunspots during the partial eclipse, and the Corona during totality.

For my next eclipse, I’d like to run 3 cameras:

  • One probably the same as the 7DII at 384mm.
  • Second camera with a wide field lens, probably 18mm to capture the wider scene and stars.
  • Third, a longer focal length scope, around 1000mm (assuming an APC-S sensor) to capture more details of the partial phases, and the prominences during totality.

The first and 3rd cameras would be on tracking mounts. The second camera would be on a fixed tripod, and could really be any kind of compact camera that was capable of timelapse shooting.

Do You Need A New Lens?

It depends what you want to photograph, and what lenses you have. Wide field lenses will let you get the surroundings, which make for excellent memory shots. Medium focal length lenses can allow you to frame some great shots, and maybe capture brighter planets and stars during totality. Longer lenses let you see the details of the Sun, prominences, and solar corona. Short of having multiple cameras, you need to make some choices and tradeoffs.

Other Tips

  • Have extra batteries for cameras, mounts, intervalometers, and any other equipment. Make sure you have fully charged or fresh batteries in everything the morning of the eclipse.
  • Remember yourself; stay hydrated, bring snacks, wear sunscreen, appropriate clothing, etc.
  • Enjoy the event. Total Solar Eclipses are rare – make sure you aren’t trying to manage too many cameras, and miss out on the experience.
  • Check your solar filters for scratches, pinpricks, etc. A pigment based pen or dab of black paint can be used to cover small holes in the filter material, and won’t really impact the image.

Summary

Solar Eclipse photography is a highly rewarding challenge. Preparation and familiarity with your equipment is key. Just remember that the time you spend behind the camera is time away from the event itself. Totality lasts only a couple minutes (or less), so be sure to strike a balance between photographing the event, and experiencing the event yourself.

Have a question or other thoughts? Leave a comment below, or find the Soggy Astronomer on Facebook.

Eclipse Prints

Select images from the 2017 total solar eclipse are available for purchase from my EclipseKit.com site starting from $20.

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