Can't see it with my eyes. Only in that picture. I suppose I could wipe it off with a paper towel, and see if I get anything. That's part of a can opener.
Apparently you can't link directly to a file on Nextcloud, if you shared a folder, the URL it gets after clicking a file, doesn't work. Some kind of JavaScript most likely.
To get the image URL to embed, I had to inspect the HTML. It would be easier to just share the one image, and the folder.
Paper towel didn't get anything. Doesn't really look like a reflection.
Different focus point, looks like something is growing on it. Like hair. Or metal pieces.
Is it like a microscope? I should buy one, and compare.
How did I get both hairy sides in focus? The focus point is supposed to be in the center. Only one little square in the center is set in the focus thing.
How are you supposed to know where to focus? I thought it was what you want in focus, apparently not.
On another note, the Sigma 60mm is smaller then my zoom lens. Not sure that's a good reason to spend $239 though.