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10-24-2013, 02:59 PM   #16
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QuoteOriginally posted by rawr Quote
Whatever is happening, it seems to work well. After two years of use, dust remains a rarity on my K-5.
Yes. And I couldn't say so about my old K10D which used the SR for dust removal.

10-25-2013, 07:24 PM   #17
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I wish they also used the SR mechanism for image stabilisation in macro shooting situations.

With large subject distances it is important to counteract rotational shake. This is what the current SR implementation does.

With small subject distances it is important to counteract translational shake. Olympus does this in-camera and a few dedicated macro lenses with built-in OS do it as well. I understand Pentax cameras lack the corresponding type of accelerometers to offer the functionality.

QuoteOriginally posted by rawr Quote
I notice if I have the dust reduction set to run at camera startup, my K-5 makes a certain sound and I feel a slight vibration from the body.
Are you sure your K-5 does not make the sound when you switch off dust reduction at startup?
You might just be experiencing the calibration of the aperture lever mechanism.
10-25-2013, 10:09 PM   #18
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QuoteOriginally posted by Class A Quote
You might just be experiencing the calibration of the aperture lever mechanism.
You are probably right.
If I turn off SR at startup, I do still hear a very faint 'crunch and buzz'.
10-26-2013, 05:00 AM   #19
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QuoteOriginally posted by Class A Quote
I wish they also used the SR mechanism for image stabilisation in macro shooting situations.

With large subject distances it is important to counteract rotational shake. This is what the current SR implementation does.

With small subject distances it is important to counteract translational shake. Olympus does this in-camera and a few dedicated macro lenses with built-in OS do it as well. I understand Pentax cameras lack the corresponding type of accelerometers to offer the functionality.
.....
This might be possible through a firmware only upgrade but not necessarily. It requires the use of linear accelerometers. All Pentax DSLR-s (at least since the k-r) have some form of accelerometer but it would not necessarily be suitable for translational shake reduction.

In the K-r for instance its only use is to set the image orientation in the EXIF data, something which needs neither accuracy nor speed. Also it can be done with a single axis accelerometer. So unless they overspecified the accelerometer it is unlikley to be of any use. (Accurate accelerometers are needed for Astrotracer, which does work on K-r but it probably uses the accelerometers in the O-GPS1 rather than the one in the camera)

In the K-30 and K-5 there is horizon correction which will require rather accurate accelerometers on two axes, which would be sufficient, but only if they have a high enough bandwidth to provide an input to the SR algorithm which I think is not very likely as most off the shelf accelerometers are designed with rather low bandwidth and optimised more for low drift.

I do wish though that they catered for this in the K-3. If we are lucky they may have put in the required hardware (faster response accelerometers) and it will be just a matter of time until they do what's needed in the firmware.

One might think of using the accelerometers in the O-GPS 1 but I don't see that working as even if the accelerometers are fast enough the serial data link to the camera is far too slow anyway.

10-27-2013, 02:34 AM   #20
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I was expecting a 5 axis stabaliser ala em5. Well can't have it all. ...
10-27-2013, 11:16 AM   #21
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QuoteOriginally posted by lister6520 Quote
This might be possible through a firmware only upgrade but not necessarily. It requires the use of linear accelerometers. All Pentax DSLR-s (at least since the k-r) have some form of accelerometer but it would not necessarily be suitable for translational shake reduction.
Actually, the Pentax SR system uses gyroscopes.
10-27-2013, 12:02 PM   #22
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QuoteOriginally posted by kh1234567890 Quote
Actually, the Pentax SR system uses gyroscopes.
Yes I know that but they also have accelerometers.

The accelerometers are used for things such as setting the orientation of the image in EXIF and horizon correction (gyroscopes cannot do that, at least not without help from accelerometers).

The gyroscopes are used for the shake reductioon, but gyroscopes are only good for reduction of angular shake. For shake reduction at close distance, in particular macro you need linear accelerometers in addition to the gyroscopes. The gyroscopes take care of the angular motion and the accelerometers would be needed to measure the sideways (translational) motion.

What I was discussing was whether the already existing gyroscopes accelerometers in Pentax cameras could be used for the second part of shake reduction, that part which is specifically needed for close range and macro shake reduction. The normal shake reduction has no use at all for accelerometers.

Last edited by lister6520; 10-28-2013 at 10:37 AM. Reason: fix typo that was contradictory
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