Re: Why is it recommended to turn off IBIS on Sony cameras when using a tripod?
GHarris wrote:
You can't feel the Earth rotating under you, that's fundamental physics, because you're on the Earth and moving just the same way and appear (to yourself) be at rest, experiencing no acceleration, and therefore no amount of IS precision will ever detect it.
That is not correct. While you can't detect constant motion, you can easily detect acceleration. You are moving on a circle around the earths axies which has an inherent acceleration towards the center of that circle. Additionally the direction of local gravity toward the center of the earth changes. There is many simple physics experiments proving this. See e.g. https://en.wikipedia.org/wiki/Foucault_pendulum.
Whatever it is that causes IS to produce blurring on a tripod, it is not the ongoing, shared, undetectable movement of the Earth.
While the native drift of IBIS is usually worse, for the precision you'd need for long exposure IS the earth rotation is indeed an issue. See https://thecentercolumn.com/2020/01/17/earths-rotation-limits-ibis-performance-to-6-3-stops/. That has nothing to do with astronomical imaging, where the astronomical mount would compensate the rotation of the earth and ideally the telescope stops rotating in absolute terms (so an ideal IS would not move a telescope on an ideal mount).
May 27, 2022 at 08:02 AM
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