The Costa Rica case from 1971 is one of the cases I still find interesting. Mostly because the data is so good, and the image exists in 17,000 × 17,000 pixels, so there is no reason to complain that it is blurry
We know exactly which camera and lens it was taken with, we know precisely where and when, at what altitude and where the sun was, so I made a 3D reconstruction a couple of years ago.
Now I see the case is trending a bit again, so I tried to use my 3D version to determine how large the object could actually have been, if it was an object. Simply by scaling it relative to altitude, so it appears the same size in the image at different heights from 0 to 2300 m.
It clearly was not right above the water, because then you would be able to see a reflection.
Up to 1000 m also does not seem possible, since you should be able to see a shadow on the ground, and there is nothing at all.
If it had been under 20 m from the camera, it would have been out of focus, so it has to be somewhere between those distances
The debate is still what it was. As always, I would say that a spacecraft from another planet is probably the least likely explanation.
It is definitely not a flaw in the glass, since it does not appear in the images before and after.
A flaw in the film is unfortunately the most boring and most likely explanation.
But it is still interesting and fun to have enough data to analyze and recreate it
Source: https://youtu.be/Bu03kUBCLS0