Flat Earthers on Youtube distribute a video that shows the ascent of a rocked to space from an onboard camera. The horizon appears flat the whole flight, which for them is proof for the flat earth. I show that instead of applying the correct lens correction to get rid of the barrel distortion introduced by the fisheye lens of the camera, the original video was deliberately distorted by a flat earther to show a flat horizon. Applying the proper lens correction however shows the horizon curved exactly as predicted by the globe model.

This is my version of the Video Flat Earth? Proof? 35mm Camera Perspective Space Experiment 2017, where the flat earther **Jason Kirby** distorted the original video from Blue Origin deliberately to show a flat horizon. The Original Video is Flight 3: GH2 Vent Cam from Blue Origin.

My video shows the real shape of the earth from ground to 240,000 ft altitude (other sources claim 103 km) and back in one single uncut shot. The original video shows only the descend of the rocked. The ascent at the beginning is the original video reversed.

I applied a proper lens correction filter in Adobe Premiere Elements of -28, the setting for a typical GoPro camera fisheye lens, and cropped the video vertically to get rid of extreme wide angle distortions and the black regions created by the correction filter. The original Field of View of about 90° gets hereby reduced to about 65°. This is the natural Field of View for humans. It corresponds to a focal length of 33.9 mm.

Note: Cropping the video does not introduce any distortions. To undo the barrel distortions, wide angle lens corrections stretch an image radially away from the center of the image, see Ground Scene Analysis of Walters Video. They do not manipulate the image in any other way.

The following images show how Jason manipulated the video. Click on the image to switch between original fisheye lens image and Jasons "corrected" image.

I took the pictures of this analysis from Jasons video: Flat Earth? Proof? 35mm Camera Perspective Space Experiment 2017.

- Jason Kirby's:
- Original fisheye
- Transformed
- Orig + Displacements
- Trans + Displacements

We can recognize that Jasons video is deliberately distorted to show a flat horizon. He "removed" the fisheye distortion by introducing other distortions. A lens correction filter would remove the fisheye distortion radial symmetric over the whole image, see Ground Scene analysis of Walters Video.

Lern more about How Lens Distortion works.

The yellow displacement lines connect two identical points on the original and the manipulated image. As the displacement lines show, he pulled down the middle field and streched the whole image horizontally considerably. This transformation applied to the image in space bends down earths horizon in the middle of the image and streches the horizon. That is exactly the transformation needed for this footage to get rid of earths curvature.

With his transformation Jason introduced other distortions: the rocket and the shadow of the rocket have obviously not the right proportions. Another sign of false correction are the mountains in the background. Compared to a Google Earth image of the area shows that they are stretched horizontally and the u-shaped desert in the background is not correct. Google Earth shows that this area is flat.

- Jason Kirby's:
- Original fisheye
- Transformed
- Orig + Displacements
- Trans + Displacements

The same transformation applied in space pulls down the middle and straightens earths horizon as expected. The horizontal stretching helps straightening the curve even more.

Lens corrections are exactly defined mathematical transformations on the basis of optical laws. They are intendet to remove e.g. barrel distortions introduced by fisheye lenses. To get the image, where we can tell the real shape of the shown objects, we must apply the correct lens correction. Not the one that "looks right", but the one that exactly reverses the distortions introduced by the lens.

The following images show how wide angle lens corrections work. Click on the image to switch between original and corrected image.

- Walter Bislins's:
- Original fisheye
- Lens Correct
- Orig fisheye + Displ.
- Lens Correct + Displ.

As you can see, a lens correction acts symmetrically about a single center. It streches the edges away from the center, the farther from the center, the more. In this way the barrel distorions of fisheye lenses get corrected.

Lern more about Lens Distortion and the Curvature of the Earth.

The lens correction introduces large black regions on all four sides of the image, so I cropped the video to get rid of this regions. This reduced the Field of View from 90° to about 65°, which is about the Field of View of the human eye. Because I cropped the image more at the bottom than at the top to get the same cinematic aspect ratio of 2.35:1 like in Jasons video, the center of the correction is now below the center of the image. In the uncropped version it is exactly at the center of the image.

We can here clearly see the curvature of the earth on the following images. How do we know that this curvature is real?

I have programmed an app Finding the curvature of the Earth. This App can calculate, how a Globe with the size of the earth would look like from any altitude under a specific field of view. In the Tab "Lens Correction with Grid", the calculated grid for this altitude and field of view is overlayed onto the image to see, wether the image matches the expectations of the globe model. The result speaks for itself.

- Walter Bislins's:
- Original fisheye
- Lens Correction
- Lens Correction with Grid

It is possible to get the real shape of the earth from video footage taken with fisheye lenses by applying the **proper** lens correction filter. As the example on this page shows, it maches the calculations of a Globe Model exactly. You don't need to turn knobs until you get a picture that maches someones expectations. You just have to know the data of the used lens und feed that into a good video editor and he spills out the real shape of the landscape, in this case the spherical shape of the earth at high altitudes.

The following facts are strong evidence that the earth is sperical:

- The lens correction filter shows a flat earth on ground and a smooth transition to a sperical shape as the rocket gains altitude.
- The shape of the earth from space on the video, after applying the lens correction, maches the shape obtained by geometrical calculations for a sphere of radius 6371 km.
- The geometrical calculations of my App are proven to be correct by compairing the calculations with images where all relevant data is known (See here).