Here we are a few days after the eclipse. The eclipse happened in perfect conditions here in Switzerland. I went near the city of Morat, a little on the south of Neuchâtel. The conditions there were very good: no clouds, Ok visibility beyond some sort of dust in the air, but that doesn't cause many issues with the imaging. A little too hot though as it happened in the middle of the heat wave, so temperatures were challenging for me... I actually went to several places trying to find the best view with the hope to catch a picture where the eclipsed sun would be behind a landmark. I was hesitating between Avenche and Morat. In the end, I decided to go to Morat because the sun would be visible at a lower altitude. In Avenche, near the ancient Roman Theater of Selley, the sun was setting behind the castle and immediately vanishing while still at 4° above the horizon. Basically just a few minutes after the maximum. In Morat, I had a few more minutes after the maximum to keep shooting.
I was also not sure how bright the sun would be eclipsed at 90% and if I would be able to take a picture of both the sun and the landmark at the same time, without overexposing the sun or underexposing the rest of the image. Turns out that even at 90%, the sun is really really bright, and I ended up overexposing the sun or underexposing the landmark...
So I kept the basic idea of doing a composite image of the eclipse showing how the sun changed every minute or so. Somehow, I ended up with the white balance off for a few pictures of the sun, I had to readjust that in post processing. Most of the pictures were taken with the OD4 filter combination. When the sun was less bright, I removed an OD1, for a total of OD3... Also to keep the parameters similar, with a 1/250s shutter speed, f/18 and and ISO 160.
Here is the setup, tripod, Fujifilm XT4, Objective FujinonXF 50-140, and my filter apparatus in front with either a 4, 3 or 2 optical density filter from Thorlabs. No active following of the sun.
On another more optical oriented issue, I almost got a fright at the start of the show, as I was setting up the parameters. I positioned the sun on one of the corner of the sensor, expecting the sun to move toward the center of the picture. When I took the first picture, I set a fast shutter speed, maybe 1/500, to be sure. The result was a picture of the sun with a dark shade, close to the side of the sensor. Immediately, I thought: "Damn, I must be going so fast with the shutter speed that it is interfering with the image exposure..." Which in itself was dumb, but I had just a few minutes before the start, I didn't had time to think too hard there. I changed the shutter speed to 1/200, still there. At that moment, I knew that it was not actually the shutter speed. There is some effect like that that can come from high shutter speed with flashes, where the shutter is so fast that the illumination from the flash doesn't last the whole time of the shutter moving in front of the sensor. Clearly not my case, as the sun is continuously bombarding us with photons, and my camera has a electronic global shutter, not a mechanical shutter. Anyway... The actual problem is my filter holder! I wrote in my last post that the holder would not bother my pictures... it was not entirely true! The issue is that the aperture of this holder is actually causing some level of vignetting, which was to be expected actually. Taking a picture of a flat white field, one can see the vignetting on the far edges of the objective. And this is what freaked me out on the moment. Typical.
Once the parameters were found and I started to shoot, I had to fight myself a lot to not change the parameters to try to find better ones during the maximum.. I eventually lost and tried to change the parameters to get the full picture sun and landmark, only to overexpose the last few pictures of the sun. I wish I didn't do that. But that was already too late, the eclipse was moving fast and it was very close to the horizon. I thought I could do the test in 1 min, and go back to the previous regimen and parameters. I also wanted to shoot the green flash, only to remember that the green flash only happens at sunset over the horizon, not behind mountains. The sun has to pas through a lot of atmosphere to see the green part of the spectrum go sideways enough to become visible in a picture. So the picture I took of the sun setting don't show any green part. Bummer. I tried anyway.
I also played a little with the shadows during the eclipse, doing the trick of punching a tiny hole in a piece of paper and observing the eclipse by looking at the projected image like a camera obscura. I did that during the 2015 eclipse when I was at EPFL. At the time, I didn't had a good camera, also my telescope was not close-by, so I could not take good pictures directly. I converted our office back then into a camera obscura and I took picture of the sun projected on a piece of paper. Good time.
Next eclipse is next year, surprisingly again in Spain, this time above Tarifa only. I guess I could go there for once, maybe take a week vacation, go there, do some windsurf and see the eclipse? Unfortunately, it is in the touristy high season, which I don't appreciate... We'll see. I was a little disappointed not to have gone in Spain to see the eclipse this year. The pictures I saw looked phenomenal over there.
