If light spreads spherically, then why do we see these light sources spread in just four (perpendicular) angles on images?

Question

Many times on this site it is said, that light spreads spherically, in all spatial directions.

Incoherent light can be made coherent making a point source but the spread is still spherical.

Why is light able to shine in a narrow beam?

Yet, we can see on a lot of images where these light sources spread in exactly four perpendicular directions. My question is why only these specific four angles, instead of seeing a spherically (or circle like in 2D) shape spreading from the light source?

First, I thought it was just an out of focus effect, but then I found a lot of out of focus images ,that show otherwise, these are exactly round as one would expect from the fact that light spreads spherically.

Question:

1. If light spreads spherically, then why do we see these light sources spread in just four (perpendicular) angles on images?

Answer 1

Light is spreading out spherically (or mostly so depending on the source). But only the bit that reaches your eye directly can be seen unless it reflects off something else.

The "cross" pattern is due to light reflecting off other surfaces in one of two ways.

Most likely it's either an artifact of your camera imaging system where reflections or diffraction inside the camera from bright sources are visible in darker fields (https://petapixel.com/2018/05/19/the-physics-behind-sunbursts-and-how-it-can-help-you-focus-your-photos/),

...or it's due to scratches/scoring on a window you're looking through (Why do lights appear like straight lines on a windshield of a car? (becomes more prominent at sunset and night))

If you can rotate your camera and the spikes rotate with it, then it's internal to the camer.