Off topic, but I think here's another image of the same airplane, also taken in Idaho: https://www.reddit.com/r/aviation/comments/6v62nl/plane_cros...

That turned out to be a fake.

https://www.reddit.com/r/pics/comments/6v6y1k/

Oh man that's hilarious considering this: https://petapixel.com/2016/01/29/nikon-awards-prize-to-badly...

I was in North Eastern Idaho and there is a similar looking contrail visible in my wide angle shots at totality so if the point of image capture happened to be just right it would be possible to have it in the frame with the sun.

That one would have been taken about 15 miles or so to the southwest of my location.

You can torch your sensor in seconds:

https://youtu.be/2TO_yZDxryQ

At Lick Observatory, they close the slit in the roof before repositioning during daytime observation (yes, that is a thing) to avoid even the chance of running into Mr. Sun.

Yeah, if you use a super-telephoto lens, then take your camera body off and change the focal point so that you are using your lens as a magnifying glass like they did in the video. No doubt. For the rest of the sane world; however, it's not quite that risky. For reference, that Leica I used in my shot is a one of a kind as it was the first lens to roll off the line when Leitz branding was changed to Leica & estimated to be worth between $12,000 to $22,000. I wouldn't have risked it if there was any risk whatsoever.

No, it is the opposite. A 50mm f/1.4 lens focus the light and the heath much more than a 300mm f/5.6. You were quite lucky with your camera I guess.

Correct.

The flux for the sun on the sensor/film/whatever is:

    Φ/4α² * 1/A²

Where Φ is the sun flux at the surface of the earth, and α is the angular diameter of the sun. A is the f-number of the lens, the only variable in this equation. It doesn't depend on focal length.

The total power over the film is:

    Φ/4πα * f²/A²

which does depend on focal length, but that is usually not the determinant factor, as for surface burns the damage depends mostly on the flux.

Surface damage mostly depends on the power density, not on total power, so it depends mostly on the aperture, not on the focal length. This makes longer focal lengths safer to point at the sun because they are slower lenses. They are also safer if you don't explicitly point them at the sun because they are less likely to catch the sun in the smaller field of view.

Burned shutter cloths on Leica M series cameras with wide angle lenses is a real problem that can happen simply if you leave the camera without a lens cap lying on a table. This is less of a problem on most other cameras, as they use metal shutter curtains.

I wonder if that guy damaged his lens while making that. That lens looks similar to one of the damaged ones in the article.

To satisfy your curiosity, he did not. The lens was borrowed from his workplace (a camera store) for the purpose of the video, and was returned unharmed.

The creator of that video hangs around on /r/photography, his comment is here: https://www.reddit.com/r/photography/comments/6xg8a7/lens_re...