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A99M2 SteadyShot with Shutter

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Post Options Post Options   Quote sybersitizen Quote  Post ReplyReply Direct Link To This Post Posted: 17 June 2017 at 06:22
Originally posted by kefkafloyd kefkafloyd wrote:

Sure. Since it doesn't have a lens mounted it is probably assuming a 50mm lens at infinity like they used to before the custom focal length setting.

That assumption has been disproven with recent cameras in the SLT line by myself and Photosopher - maybe others. Link. It was never proven with cameras in the A100 generation, so it's simply a guess that's been perpetuated.
 



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Post Options Post Options   Quote kefkafloyd Quote  Post ReplyReply Direct Link To This Post Posted: 17 June 2017 at 14:13
Originally posted by sybersitizen sybersitizen wrote:

Originally posted by kefkafloyd kefkafloyd wrote:

Sure. Since it doesn't have a lens mounted it is probably assuming a 50mm lens at infinity like they used to before the custom focal length setting.

That assumption has been disproven with recent cameras in the SLT line by myself and Photosopher - maybe others. Link. It was never proven with cameras in the A100 generation, so it's simply a guess that's been perpetuated.


I even have posts on that page, so shame on me for not remembering.
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Post Options Post Options   Quote analytical Quote  Post ReplyReply Direct Link To This Post Posted: 17 June 2017 at 19:04
Originally posted by Swede101 Swede101 wrote:

First, for a solid body, 5 axis stabilization does not exist. 5 axes stabilization is an "invention" by marketing people, originally by Olympus.
Well, yes and no.

Certainly some of the illustrations that seem to show the show the sensor pitching and yawing relative to the body are wrong. The sensor must stay in the plane perpendicular to lens axis or focusing across the entire sensor would be impossible. And descriptions have sometimes been just as misleading.



Olympus Source Page

So marketing is definitely guilty of their usual exaggerations.

Roll of sensor relative to the body is possible, along with the original 2 axes, vertical and horizontal translation.   = 3 axes.   


But sensing 5 axes of camera movement is possible and important for some circumstances.   While the sensor can only move in the focus plane (3 axes) relative to the camera, the amount it needs to move to correct for shake depends on whether the shake is angular pitch and yaw or translational x and y.

The clearest example is macro distance and focus where x and y shake moves the image a long way on the sensor (up to 1 to 1) compared to a telephoto used at telephoto distances. In that case translation shake hardly moves the image on the sensor at all. On the other hand a telephoto moves the image much more for a given angular shake than a shorter focal length lens at the same distance.

FWIW the original 2 axis anti-shake sensed only rotation, because rotation shake dominates image movement on the sensor in most circumstances. And those cameras advised turning AS off in macro.    

       
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Post Options Post Options   Quote sybersitizen Quote  Post ReplyReply Direct Link To This Post Posted: 17 June 2017 at 19:28
Originally posted by analytical analytical wrote:

FWIW the original 2 axis anti-shake sensed only rotation, because rotation shake dominates image movement on the sensor in most circumstances. And those cameras advised turning AS off in macro.

Indications do suggest that pure X/Y shake correction was not supported; and I share the opinion that it 1) was absent and 2) would only rarely be needed anyway if it existed. However, I'm not aware of a reliable source - an explicit Minolta/Sony statement, for example - that tells us we're right.
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Post Options Post Options   Quote analytical Quote  Post ReplyReply Direct Link To This Post Posted: 17 June 2017 at 21:49
The original Minolta brochures say specifically that the sensors are angular. One or the other of us has posted it before I think. I'll look at mine.
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Post Options Post Options   Quote sybersitizen Quote  Post ReplyReply Direct Link To This Post Posted: 17 June 2017 at 22:02
Originally posted by analytical analytical wrote:

The original Minolta brochures say specifically that the sensors are angular. One or the other of us has posted it before I think.

I posted the description from the 7D (2004) on the previous page; but that still doesn't exactly exclude an X/Y capability, especially in later iterations up through last year.
 



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Post Options Post Options   Quote Miranda F Quote  Post ReplyReply Direct Link To This Post Posted: 19 June 2017 at 15:21
Certainly the 2-axis IBIS on my A58 is worse than useless in macro. The trouble I have is remembering to switch it off ...

In terms of how likely translation versus angular movements are to occur, they depend on the position of the C of G handheld. I'll have to try comparing IBIS with a short lens to that with a long lens of the same FL. But as the 5-axis camera is sensing both it doesn't have to guess.

Re sensor movement, I assume that most of the sensors do purely move in X and Y (as well as a Z-rotation now), but I wonder if the new magnetic support can work in angle as well? I guess with small movements the two are equivalent, but a large movement of a short FL lens at wide aperture might produce an angled plane of focus at the sensor which would leave two sides OOF. I wonder if anyone has seen that?
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Post Options Post Options   Quote sybersitizen Quote  Post ReplyReply Direct Link To This Post Posted: 19 June 2017 at 17:32
Originally posted by Miranda F Miranda F wrote:

I assume that most of the sensors do purely move in X and Y (as well as a Z-rotation now), but I wonder if the new magnetic support can work in angle as well?

That could only make any sense if a lens has IS that works by simple rotation of the optical axis that causes the focal plane to assume some angle other than perpendicular to the lens barrel. Is that how lens IS works? Or does it work by skewing the light path so that the focal plane remains unchanged and is only shifted in X/Y?

For normal non-IS lenses, it would just throw the focal plane off. It could be useful for very mild tilt/shift effects, though.

Edited by sybersitizen - 19 June 2017 at 18:17
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Post Options Post Options   Quote Miranda F Quote  Post ReplyReply Direct Link To This Post Posted: 20 June 2017 at 10:15
Originally posted by sybersitizen sybersitizen wrote:

That could only make any sense if a lens has IS that works by simple rotation of the optical axis that causes the focal plane to assume some angle other than perpendicular to the lens barrel. Is that how lens IS works? Or does it work by skewing the light path so that the focal plane remains unchanged and is only shifted in X/Y?


To change the light path in the lens while keeping the axis constant would need two titlable elements, not one. Therefore I assume all (consumer-grade, at least) in-lens stabilisation alters the axis.
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Post Options Post Options   Quote sybersitizen Quote  Post ReplyReply Direct Link To This Post Posted: 20 June 2017 at 16:55
Originally posted by Miranda F Miranda F wrote:

Originally posted by sybersitizen sybersitizen wrote:

That could only make any sense if a lens has IS that works by simple rotation of the optical axis that causes the focal plane to assume some angle other than perpendicular to the lens barrel. Is that how lens IS works? Or does it work by skewing the light path so that the focal plane remains unchanged and is only shifted in X/Y?

To change the light path in the lens while keeping the axis constant would need two titlable elements, not one. Therefore I assume all (consumer-grade, at least) in-lens stabilisation alters the axis.

I'm not suggesting the axis is constant; the axis pretty much has to change for in-lens IS to do something. What I wonder is what happens to the focal plane. Since there are plenty of examples of in-lens IS and no examples of tilting sensor planes to operate with them, we have to assume that either the plane does not change, or it changes so minutely as to not cause issues.
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