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 p.2 #15 · Why is it recommended to turn off IBIS on Sony cameras when using a tripod? | |
There's another exception: Pentax.
K1 and K1 MKII have Astrotracer. Other Pentax bodies can do it with a clip on GPS device.
There are some weaknesses, limitations and pros.
It's easier to set up alignment.
It's no good wider than 24mm.
The sensor can only move so far, so exposure time is limited.
It takes up no room in your bag and weighs nothing (K1).
GHarris wrote:
Can't do that without knowing where you're pointing. The way the sky moves depends on your orientation and location.
The only exception to this is if you attach your camera to an "Equatorial mount" (what people in photography communities commonly call a "tracker" in its various forms), which is physically aligned to the axis of the Earth's rotation and keeps up with it - which thereby negates the need for IS.
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.
A camera with a built-in "plate solver" - a process of taking a photo, and then recognising the stars in the frame, and thereby determining location and orientation - could be the start of an IS-based tracking system, albeit a slow one - it would need to take multiple photos, either of the same location set apart by a time interval (to not just determine "what bit of sky is this?", but also, "where am I observing it from and, therefore, how is it moving?"), or of two different areas of the sky at almost the same time. It would, like the use of an equatorial mount, be an optical-observation-based correction of the image, not a movement/force-detection based method. But it would be very limited in range of movement / permissible exposure time, and the camera would have to be turned and reframed/reset often. And would do what computerised tracking mounts, or the simplest equatorial mounts, essentially already do for you. IS is there for the correction of small, variable movement in varying directions, not constant, ongoing movement in a steady direction.
Whatever it is that causes IS to produce blurring on a tripod, it is not the ongoing, shared, undetectable movement of the Earth.
At least, that's how I understand it. Perhaps I am mistaken. My explanation does not account for the ways that weather appears to be gently affected by the Earth's rotation, for example. I would be happy to be corrected. I fear I have probably misunderstood what point you were trying to make / what you were trying to say. Sorry if I'm derailing the thread....Show more →
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