Next week (July 2nd, 2019) there will be a total solar eclipse in Chile and Argentina. We will be traveling to Chile to see it, and I’ve done a lot of planning to hopefully get a good viewing location and photo. I shot a total solar eclipse in Wyoming in 2017, and thanks to the bracketed exposures I made then, I’ve been able to calculate what my optimal settings should be. Though this can vary widely depending on cloud/haze conditions and the angle of the sun, it’s a good starting point, better than trying to find the exposure as totality happens, and missing the experience of seeing it with your own eyes. Here is my plan:
Bracketed Exposure - 7 shots at ± 1
I’ll shoot with an intervalometer/tripod to avoid camera shake and being able to shoot without even looking at the camera. It will be pre-set in full manual mode and ready to go, all I need to do is hit the shutter at the right moment, and enjoy the show with my own eyes the rest of the time.
I calculated that there’s a 3 stop difference between the optimal corona exposure and the optimal sky/ground exposure, so bracketing is needed if you aim to shoot more than just the sun and nothing else. 7 brackets is the max for the 5D IV so that’s what I’ll use. Last time in Wyoming I shot at ±2 and that was overkill, most shots end up being trash. ±1 gave me the right range with a little extra on both ends.
7 brackets at ±1 exp
ISO 640 - f/8 - 1/10 sec
This is optimal from what I calculated. The middle point is favoring the corona by a third of a stop, it’s a perfect starting point.
Windy or 300+mm lenses
ISO 1250 - f/8 - 1/20 sec
If I’m afraid of the camera shaking too much due to wind, or because of the long exposures (the longest exposure will be at almost a whole second), I’ll bump the ISO by one stop and get a faster shutter speed.
Telephoto needing sharper fg/bg
ISO 2500 - f/16 - 1/10 sec
If I happen to have a relatively near object as foreground, like a tree or house, and I want it sharp enough to read when using 200+mm. I need a smaller aperture, so I sacrifice the ISO and add some noise, I don’t want to sacrifice my shutter speed with a telephoto.
All of these settings are assuming a 7 brackets exposure at ±1 , so be careful! It’s just the middle point between the brackets. These are my optimal settings (no bracketing) for either just the sun corona or land/sky:
Optimal SUN/CORONA exposure
ISO 640 - f/8 - 1/20 sec
Optimal LAND/SKY exposure
ISO 640 - f/8 - 0.4 sec
Google Earth / Google Maps Planning
I used Google Earth to preview the sun angle. You can specify a date, and go to ground level view to see the angle, and quickly toggle between Street View (if available) and the 3D view with a single button, so it’s super handy. I start by creating a map in mymaps.google.com, then export that as a live KMZ and import it to Google Earth. Once the points are imported, it looks like this:
And Google Maps (after adding colors and images to every point) looks something like this:
The biggest issue with Google Earth is that the sun shows up as a huge flare that is deceiving in scale, so I created Photoshop overlays with the actual sun size so I could visualize it better:
The general location for the best viewing spots was decided based on lots of searches from eclipse sites like Eclipsophile, NASA, and other random sites found with Google. The goal was to find the area with the least likelihood of having cloud coverage, that still had an interesting view for photography, and that wouldn’t be too crowded. In this case, the Road 41 is the main choice in Chile, near Vicuña (where it is driest and least likely to be cloudy). Vicuña itself doesn’t have the best mountains to contrast against the eclipsed sun, that’s where Google Earth came in handy to find nearby areas that could look better.
After a lot of work traveling on Street View and Google Earth, I came up with these potential locations, and created a nice printout that will come in handy when we go scout the area next week, especially if we don’t have cell data:
Notice the last page: it has my optimal camera settings, and also all the relevant info about the timing of the eclipse. I want that handy, in print with a backup, not on my phone. I don’t want to fumble with the camera at the last minute, I’ll have it preset and ready to go. If light conditions vary I might adjust accordingly, but it will be all preset to what I already calculated.
Map Color Coding
I color coded the map in the following way:
💛 Best spots, sun setting over a mountain
🧡 Second bests, backups
❤️ Good but risky, sun might be occluded
💙 Sun will be too high with no foreground
💚 Not a great view but nice trees as foreground
💜 Places to rush to after totality, for partial eclipse photos
🖤 Spots I don’t like anymore but didn’t want to delete yet
A really important set is the 💜 markers. Because most of my locations are planned with the sun almost touching the mountains, as soon as totality is over, the sun will drop and we’ll be in the shadow, not able to enjoy the rest of the partial eclipse. The 💜 indicate areas to drive to so we can see the rest of the eclipse for an extra 40 minutes or so, and each 💛 has a nearby 💜 location that is easy to get to. These also will serve as backups, in case there is a miscalculation or clouds and the 💛 spots actually have the sun occluded, then we can rush to the backup location so we don’t miss the event.
I also gave each general location a letter, so they are easy to identify the areas. So there’s a B1, B2, B3, and also a Bx (the 💜 or extension for the B area). This makes it easy to focus on just one area after we decide which general area we’d prefer, and be certain that each area has a backup plan.
Enjoying the Eclipse
The most important part of this amazing phenomenon is to be able to enjoy it, to see it with your own eyes (after totality only! Don’t burn your retinas!). Of course I would love to get an amazing photo from this event, but if the choice is between a great photo and a great experience, I’ll take the experience. This is the reason for so much planning, it ensures that at the moment of totality, I will be set up, looking up, not looking at my camera. I will hit the shutter with an intervalometer already in my hands, not having to double-check my settings or previewing my shots, and my eyes will be focused on the corona.
There will be 2 minutes and 30 seconds of totality. Every millisecond is precious. I need time to look up, to look around, to feel the breeze created by the sudden temperature shift, to listen to the sound of birds quieting and disquieting, to let my eyes adjust to the new light levels. I can’t be messing with a camera during those precious moments. At most I’ll sacrifice 10 seconds to zoom in (blindly) and take another series of shots, but the goal is to be there and experience the eclipse.
And what if it gets cloudy? Then we are fucked. Try again in 2024.