If we can’t see a distant ship, then it is because of one of these reasons:

- Our eyes have limited angular resolution and are unable to resolve the ship at that distance.
- The atmospheric condition is limiting our visibility.
- The curvature of the Earth obscures the ship.

Flat-Earthers are keen to demonstrate that a previously invisible ship at a distance can be made visible by zooming in. They take this fact as ‘proof’ that the curvature of the Earth doesn’t exist. They are wrong. The curvature of the Earth is not the only reason a distant object is not visible.

Zooming in on a distant object alleviates the problem of the limited angular resolution of our eyes. Our normal eyesight does not have sufficient angular resolution to make out the distant ship. After zooming in, the field of view is now reduced, and our eyes can resolve the object. Some digital camera’s sensors have higher resolution than our eyes, and that helps too.

Zooming in cannot see through limited visibility caused by atmospheric conditions, and certainly cannot see through the completely opaque barrier in the form of the curvature of the Earth.

If the ship is already behind the curvature of the Earth, then no amount of zoom can make the ship reappear.

## Analysis of the Pictures in the Illustration

The pictures in our illustration are screen caps of a YouTube video from a victim of flat-Earth.

In the end, the owner of the video told us the maximum amount of zoom is 200×. From Internet search, a popular camera with a 200× zoom is Canon PowerShot SX50 HS. Its base focal length is 24mm (35mm eq). Thus, 200× zoom is 4800mm (35mm eq).

Using the *Camera Field of View Calculator,* we can find out that at 4800 mm focal length, its horizontal field of view is about 0.43°.

From the picture, we need to estimate what is the length of the ship. Let’s assume the ship is 20 m long. Looking at the shape of the ship, the number looks realistic.

Then, we can now calculate the distance to the ship from the observer using trigonometry: distance = 20m / tan(0.43°) = 2665 m.

Assuming the height of the observer from sea level is 2 m, then the distance to the horizon is 7140 m. It turns out the ship is not farther than the horizon, and can’t be possibly behind the curvature. In fact, it is not even close.

## Reference

- Visibility – Wikipedia
- Zoom lens – Wikipedia
- Camera Field of View Calculator