Strange-shaped light in your footage? Focus error and digital zoom

7 min read

A bright point in the sky, you zoom in with your phone, and suddenly a pulsating disk, ring, triangle or rippling, colorful "jellyfish" appears on the screen. Footage like this regularly circulates as UFO videos, yet most of the time the same thing is behind it: the camera cannot focus on a tiny, distant light, and the digital zoom magnifies the error too. We show you how to recognize it, why this footage is so convincing, and how you can check what you recorded.

What is a focus error?

A camera produces a sharp image when the lens is set exactly to the distance of the subject being photographed. If it isn't, every point becomes a blurred spot. In daylight this looks like simple blurriness, but at night, when the image contains only a few points of light, the effect is quite different: an out-of-focus point of light is not a faint dot but a large, evenly glowing disk whose edge is often sharper than its center. Photographers know this as bokeh.

The shape of the spot is determined not by the light source but by the inside of the camera. It traces the lens aperture, that is, the shape of the opening that lets light in: with a round aperture it is a circle, with a bladed aperture a hexagon or octagon, and with other optics it can even be a triangle or a "donut" with a hole in the middle. If the focus shifts in the meantime, the spot grows, shrinks, pulsates.

The autofocus of phones and compact cameras is especially error-prone at night. A tiny point of light against a dark background gives it nothing to "grab onto," so the camera hunts back and forth, and in the footage the light rhythmically swells and then contracts.

What is digital zoom?

Optical zoom actually brings the subject closer by moving the lenses. Digital zoom, by contrast, only crops the center of the image and enlarges it: it sees no new detail, it just stretches the existing pixels. At high magnification the image becomes blocky, washed out and blotchy because of compression, and strange colored fringes, a "halo," can appear at the edges.

Modern phones go further than this: using several consecutive frames and artificial intelligence, they try to calculate what the enlarged detail might look like. This works well on text or faces, but with an unknown point of light the software can also "draw" edges, patterns and shapes that are not there in reality.

High magnification also magnifies hand shake. At 30-50x zoom even the smallest movement turns into jumping and zigzagging, and the image stabilizer tries to compensate for this, which looks like sudden, "impossible" changes of direction.

What does it look like?

A disk, ring or polygon, often darker in the center and brighter at the edge.
It pulsates or "breathes" as the autofocus hunts.
It ripples, shimmers, changes colors, especially with a low-lying star or planet whose light is distorted by the movement of the atmosphere.
Every point of light in the image has the same shape: the stars, the aircraft's lights and the "object" too.
The image is grainy, blocky, smeared if it was taken with high digital zoom.
It suddenly jumps, zigzags, while the background (if visible) moves along with it.

Why is it misleading?

The shape looks like a "structure." The donut-shaped disk, the dark center, the polygonal edge look as if they were the outline or window of an object.
To the naked eye it is only a point. The observer sees a bright star or planet, but something quite different on the phone, and believes the camera "sees more" than their eyes.
The pulsating looks alive. Focus hunting and atmospheric shimmer make it seem as if the object itself were changing its shape.
The zigzagging. Magnified hand shake is easy to mistake for the object's own, incredibly fast motion.
The zoom seems trustworthy. Many people think the higher the magnification, the more accurate the image, whereas digital and AI zoom are least reliable precisely in the details.

Focus error or real shape?

The best telltale sign is uniformity: if there are several points of light in the image and each one has the same shape, the same orientation, and the same "windowed" center, then the shape comes from the camera, not from the objects. Next to a genuinely triangular object, the stars cannot be triangles as well.

The second sign is focusing: if you set the focus manually to infinity, or first focus the camera on the Moon and lock it there, the large disk shrinks into a tiny, sharp point.

In focus, the stars and the aircraft's light are tiny points; out of focus, each becomes a spot of the same shape. The shape of the spot comes from the camera's aperture, not from the light source. Sky Glitch chart

Known cases

The "pyramid-shaped UFOs," 2019. In July 2019, off the coast of San Diego, the crew of the destroyer USS Russell filmed lights through a night-vision device that looked like blinking, triangular objects in the footage. The video was made public in 2021 by Jeremy Corbell, and the Pentagon confirmed that it was taken by Navy personnel, but gave no explanation. According to Mick West's analysis, the triangles are out-of-focus points of light, their shape coming from a triangular opening in the optics. This is indicated by the fact that the star-like points in the background are the same triangles too, and the blinking of the brightest "pyramid" matches the blinking lights of an aircraft.

The "rippling orb": Venus at high zoom. In footage taken with high-zoom compact cameras (for example the Nikon P900), Venus or a bright star often appears as a rippling, colorful, shape-shifting orb. The camera cannot focus on the point-like light, so it records a bokeh disk on which the movement of the atmosphere appears magnified. The effect can also be reproduced in a laboratory with a small light source and air movement created by a candle, and it disappears with manual focusing.
Samsung's "Moon photos," 2023. A Reddit user put a deliberately blurred photo of the Moon on their monitor and then photographed it with a Galaxy S23 Ultra. The phone's image showed details that were not present in the blurred original. According to Samsung, the phone recognizes the Moon, works from several frames, and enhances the details with artificial intelligence. This case shows well that the details in high-magnification phone images do not necessarily record reality.

How can you check, and what should you do?

Also take footage without zoom. A wide-angle shot that also shows the trees, houses and horizon reveals a lot about the light's position and movement.
Focus manually. On many phones the focus can be locked by touching and holding the screen. If the disk shrinks into a point, it was a focus error.
Look at the other points of light. If the stars and lights have the same shape, the shape belongs to the camera.
Brace the phone. A fence, a car roof or a tripod eliminates the zigzagging caused by magnified hand shake.
Check the sky. Use a star map app to see whether there is a bright planet (Venus, Jupiter) or star in that direction. Near the horizon these "ripple" the most.
Turn off scene optimization if your phone allows it, and see how much the image changes.
Keep the original file. Social media sites compress video further, which introduces new errors into the image.

Quick identifying signs

Disk, ring or polygon, often with a darker center
Every point of light in the image has the same shape
Pulsates, "breathes," ripples
To the naked eye, only a bright point
Shrinks into a point with manual focusing

The sober take

A point of light recorded out of focus appears not as a point but as a disk, ring or polygon showing the shape of the camera's aperture, and it pulsates and ripples because of the hunting autofocus or the movement of the atmosphere. Digital zoom magnifies this error and hand shake as well, and AI processing can even draw nonexistent details onto the image. If every point of light in the image has the same shape and shrinks into a point with manual focusing, the shape comes from the camera.