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11-19-2012, 03:20 PM   #16
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QuoteOriginally posted by vonBaloney Quote
No, I'm talking about hand-holding a macro or near-macro shot. If you're on a tripod or rail, you'd have the SR off anyway, so that's what the OPs question was about -- why doesn't SR work well at close distances? It is assumed if you are using SR you're hand-holding the camera, and at that close distance your hand shake (that would matter) would include forward/back/sideways/rotation -- everything.
Me too, when hand holding camera for macro shots I usually move the camera back /forth to focus as the hit rate is better than if using focus ring. It's very difficult to hold the camera steady and turning focus ring at the same time.

11-19-2012, 03:33 PM   #17
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QuoteOriginally posted by vonBaloney Quote
Again, it is still all movement parallel to the focal plane that it is correcting for, ...
No, the SR is correcting for rotational movement, as Fogel70 wrote.

The SR mechanism uses in-plane X-Y movement and rotation to compensate for the rotational movement but that doesn't mean it compensates for camera position translation shake.

A few macro lenses with an optical SR system sense translational movement and compensate for it, but the in-body SR of Pentax cameras does not even detect the translational movement.
11-19-2012, 03:37 PM   #18
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QuoteOriginally posted by Class A Quote
No, the SR is correcting for rotational movement, as Fogel70 wrote.

The SR mechanism uses in-plane X-Y movement and rotation to compensate for the rotational movement but that doesn't mean it compensates for camera position translation shake.

A few macro lenses with an optical SR system sense translational movement and compensate for it, but the in-body SR of Pentax cameras does not even detect the translational movement.
You'll have to put that in English. Define "rotational" in the sense that you mean.
11-19-2012, 04:31 PM   #19
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Check this video of Olympus OM-D 5-axis image stabilization.

Pentax 3-axis SR can detect and compensate for what Olympus call - vertical angle rotation, horizontal angle rotation and rolling camera shake.

11-19-2012, 04:39 PM   #20
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QuoteOriginally posted by Fogel70 Quote
Check this video of Olympus OM-D 5-axis image stabilization.
OLYMPUS OM-D - 5-AXIS IMAGE STABILIZATION - YouTube

Pentax 3-axis SR can detect and compensate for what Olympus call - vertical angle rotation, horizontal angle rotation and rolling camera shake.
Aha...ok so you are saying Pentax cannot compensate for what they are calling "shift", and I was thinking the only thing it could compensate for was shift and "rolling camera shake". I'll have to take your word for it. I don't even see how it is possible to compensate for the rotation as they show it, so that is just over my head I guess. And it seems like "shift" would be easy so why can't it do that? (It also seems like shift is what needs to be compensated for primarily.)
11-19-2012, 10:54 PM   #21
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QuoteOriginally posted by vonBaloney Quote
And it seems like "shift" would be easy so why can't it do that? (It also seems like shift is what needs to be compensated for primarily.)
Pentax DSLRs cannot compensate "shift" (translational) movement since they don't have the respective sensors. However, as Fogel70 already wrote, the image blur introduced by the camera rotating around the pitch and yaw axes dominates by far with larger distances.

Imagine a laser point hitting a wall in 20m distance. If you shift it by one mm, the point it projects will also just shift by one mm. If you slightly rotate the laser pointer, however, the displacement of the projected point will be much larger. The amount of displacement corresponds to the image blur introduced. You'll also notice that the point movement can be counteracted with a shift movement. At infinity, a rotational movement is equivalent to a translational movement. The closer the subject, the less well compensating rotational motion with a translational shift works.

Last edited by Class A; 11-19-2012 at 10:59 PM.
11-19-2012, 11:09 PM   #22
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QuoteOriginally posted by Class A Quote
Pentax DSLRs cannot compensate "shift" (translational) movement since they don't have the respective sensors. However, as Fogel70 already wrote, the image blur introduced by the camera rotating around the pitch and yaw axes dominates by far with larger distances.

Imagine a laser point hitting a wall in 20m distance. If you shift it by one mm, the point it projects will also just shift by one mm. If you slightly rotate the laser pointer, however, the displacement of the projected point will be much larger. The amount of displacement corresponds to the image blur introduced. You'll also notice that the point movement can be counteracted with a shift movement. At infinity, a rotational movement is equivalent to a translational movement. The closer the subject, the less well compensating rotational motion with a translational shift works.
Ah, so the *sensor* is in fact merely "shifting" to compensate for the rotational movement. That's what I was getting it -- I didn't see how it was possible for the sensor to be doing anything other than moving laterally to compensate (for any kind of movement), and in that I am correct. We'll call that shift-for-rotation. So the additional pure shift-for-shift compensation that the Olympus is doing is really only valuable at close distances...
11-20-2012, 12:56 PM   #23
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QuoteOriginally posted by vonBaloney Quote
Ah, so the *sensor* is in fact merely "shifting" to compensate for the rotational movement. That's what I was getting it -- I didn't see how it was possible for the sensor to be doing anything other than moving laterally to compensate (for any kind of movement), and in that I am correct. We'll call that shift-for-rotation. So the additional pure shift-for-shift compensation that the Olympus is doing is really only valuable at close distances...
On the K-30, apart from moving left<>right and up<>down it can also rotate (clockwise/anticlockwise) by a few degrees. On the K-r the mechanism can also rotate the image sensor it cannot actually sense rotational movement so does not compensate for it. The K-r only uses the rotational in conjunction with the O-GPS1 for the star tracking function - in all other situations the rotational movement is locked.

On the K-30 the clockwise/anticlockwise motion is used to compensate for rotational shake and also for automatic horizon correction.


edit forgot to mention:
The K-30 can actually sense translational movement so in that respect it could compensate for shake in macro shots but there is a snag. The Pentax autofocus system has no knowledge of the absolute focus distance as the lenses do not report it. The lens only gives a very rough indication, such as far, medium distance, near or macro. To correctly compensate for translational movement the camera would need to know the actual subject distance to within a few mm. In theory one could design it so that the photographer manually enters the subject distance but it would not be practical at all and not worth the bother.
There are some clever things that Pentax could do to get the camera to know focus distance but I doubt they would find it worth doing and in any case it would need very detailed lens information tables to be stored in the camera.


Last edited by lister6520; 11-20-2012 at 01:06 PM.
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