[seszett]

It's explained here:

> Your camera, which is using its IBIS system to attempt to keep everything as still as possible, may not realize that you are rotating with your subject and will instead try to zero out any rotation of the camera, including that of the Earth

The problem is that the stabilization system tries to compensate for the rotation of Earth (because it can't make the difference between the rotation of Earth, which shouldn't be compensated for, and the movement of the holder which should be).

So it would work if you were taking a photo of a subject not rotating together with the Earth. Like the stars.

[tetris11]

I guess I couldn't quite grok how IBIS would measure the Earth's rotation whilst being on Earth, but as I've now just learned (through various slaps of the forehead) a perfectly vertical spinning gyroscope will definitely tilt with time due to the Earth's rotation and this is measurable to high degrees of precision.

[anilakar]

Not just randomly tilt - it will align itself with the poles of a spinning celestial body. It's used in applications that can't rely on correct magnetic variation, like surveying and aircraft inertial navigation systems.

[thrdbndndn]

Why does it stop at Earth's rotation? What about revolution around the Sun?

[seszett]

It also does track the revolution of the Earth around the Sun, and that of the Sun around the Milky Way, as well as the various influences over the Milky Way that make it go less than straight on its way towards the Great Attractor.

Those movements just happen to be slow enough that they don't limit image stabilization to 6.3 stops.

[thrdbndndn]

I still don't quite get it.

Under what definition the Earth's revolution is "slower" than its rotation?

Why can the camera's stabilization system detect the rotation and correct it (and causes undesirable result) but not the revolution?

[_ph_]

The relevant "speed" is the change of the direction you are pointing at. The Earth rotates around itself in 24 hours, but around the Sun in 365 days, so the daily rotation is 365x as fast. We also rotate around the center of the Milky Way every couple of hundreds of millions of years.

[thrdbndndn]

Ah, so the angle (orientation?) is what actually matters? It makes sense now.

Thanks!

[_ph_]

At least with respect to the influence of the Earths rotation. With respect to compensating actual camera shake, the modern systems correct 5 axis's. 3 for rotation around the 3 space axis's, and 2 translational, which leaves only motion towards or away from the motive uncorrected for (which usually only expresses itself in the need of refocussing, but that usually is far beyond camera shake, except for macro photography).

[zamalek]

Per my other comment: Earth isn't attached to the sun, the sun isn't attached to the galactic center (they are orbiting). They are independent rotational frames of reference. They are also gyroscopes in their own right.

As far as taking pictures of other things on Earth, at least. Taking a picture of another planet/star/galaxy would also face similar challenges.

[thrdbndndn]

What's the difference between our "attachment" to Earth compared to Earth's attachment to the Sun? Aren't both doing circular motion due to gravity (in us-Earth's case, gravity + support force from the ground) and inertia?

[zamalek]

The Earth is in freefall above the sun. We are not in freefall. https://en.wikipedia.org/wiki/Free_fall

[blueflow]

It doesn't.

[Euphorbium]

Eventually we will have to compensate for gallactic rotation.

[viraptor]

I never thought of that one. It's fun to think "we know the whole universe isn't spinning very fast, because our gyros are stable". Feels both obvious and somehow bigger-than-life to me.

[zamalek]

We are not kinetically bound to the galactic center, there is no friction causing earth to remain "upright" in respect to the galaxy. Earth is also a freely rotating inertial body and, even though wobbly, it is itself a gyroscope.

The next level of stabilization would probably be gravitational waves.

[jerich]

Anyone who’s read the short story “The Billiard Ball” by Asimov would have taken it into account.