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12-04-2011, 07:34 PM   #31
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QuoteOriginally posted by Gimbal Quote
It's the SR mechanism. And as far as I know all Pentax cameras with SR is sometimes silent and sometimes audible. So the K20 isn't always silent, and the K7 isn't always audible.

Focal length affects the SR (when SR is activated) and the sound emitted. Different play in the mechanism can cause different cameras to be more or less audible.

Gimbal,

May I ask how you know the SR is the source of the whirring? Is it documented somewhere?
I'm not trying to argue otherwise, I'm simply curious.

Tim

12-04-2011, 08:05 PM   #32
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Incidentally, this question was addressed here previously:
https://www.pentaxforums.com/forums/pentax-dslr-discussion/91083-pentax-k-x-a...-liveview.html
and in other threads too, I believe.

I'm satisfied with Gimbal's (and Wheatfield's) description of the probable reason; but for those who aren't satisfied why not simply contact Pentax and ask them?
12-05-2011, 01:18 AM   #33
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QuoteOriginally posted by all thumbs Quote
Gimbal,

May I ask how you know the SR is the source of the whirring? Is it documented somewhere?
I'm not trying to argue otherwise, I'm simply curious.

Tim
I deduced it from observing the SR on my first DSLR (the K10d), a lot can be learned by only watching and experimenting (and reading some patents).

For instance, try a long exposure without a lens attached. Watch the actual sensor plate and listen while you "shake" the camera during the exposure. Try it with SR on/off. You will clearly see how the sound correspond to the sensor movements.

Last edited by Gimbal; 12-05-2011 at 01:31 AM.
12-05-2011, 01:47 AM   #34
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Gimbal,

Ok. Thanks.
I'll get my K-7 out and do some messing around.

Tim

12-05-2011, 02:16 AM   #35
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QuoteOriginally posted by ChipB Quote
I have both a K20D and a K-x - both sound the same in live view - some sort of "whirring" noise. Never noticed it before, but then I've never put my ear up to the camera before!!
Interesting. On all my cameras, I can hear the noise with no effort, even over ambient noise. On my friend's K20D I couldn't hear it even though I listened intently in a silent environment. If your K20D is as noisy as a K-x, it sounds like there is some significant variation between cameras in this respect.
12-05-2011, 02:21 AM   #36
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QuoteOriginally posted by pentup Quote
Incidentally, this question was addressed here previously:
https://www.pentaxforums.com/forums/pentax-dslr-discussion/91083-pentax-k-x-a...-liveview.html
and in other threads too, I believe.
Interestingly, the last answer proposes a different theory than SR:

QuoteOriginally posted by rwik78 Quote
In live view the mirror is locked up (similar to the sensor cleaning procedure) so that the image is projected directly on the sensor. As the action of "holding up" the mirror is elctro-mechanical, there is some sound associated. To verify this, simply enter sensor cleaning mode, you shall hear the same noise. Also, when you enter LV, you hear a click, that's the mirror being lifted.
Not saying it's the right answer, I'm just pointing out that multiple answers were given for this question.
12-05-2011, 02:33 AM   #37
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Just another thought: why would SR in Pentax cameras be noisier than compared to an Olympus Pen? I have a feeling that Sony cameras wouldn't have this noise either.
12-05-2011, 05:01 AM   #38
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QuoteOriginally posted by Laurentiu Cristofor Quote
Just another thought: why would SR in Pentax cameras be noisier than compared to an Olympus Pen? I have a feeling that Sony cameras wouldn't have this noise either.
They are using entirely different systems for controlling the sensor. Pentax uses voice coil type motors (pretty much identical to those found in hard drives controlling the arm with the read/write heads. Where Sony (if I recall correctly) uses some kind of ultrasonic motors.

I don't know what Olympus uses though. But the main thing is that the systems are very different, probably due to patents. (I'm guessing here).

12-05-2011, 05:08 AM   #39
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QuoteOriginally posted by Laurentiu Cristofor Quote
Not saying it's the right answer, I'm just pointing out that multiple answers were given for this question.
Usually when the mirror is up, the shutter is also up, and thus the sensor plate is held in position by the SR-system motors. But maybe the mirror also makes some sound? I don't know.
12-05-2011, 09:48 PM   #40
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QuoteOriginally posted by Gimbal Quote
Usually when the mirror is up, the shutter is also up, and thus the sensor plate is held in position by the SR-system motors. But maybe the mirror also makes some sound? I don't know.
I wasn't trying to revive that explanation, I was just pointing out that the quoted thread ends up in a rather ambiguous way.

I played more with my cameras, and your explanation matches the behavior I observed. I am surprised by the implications.

It sounds like the sensor plate is lying around all the time and only gets moved into place at the time the exposure is made or the mirror is lifted for cleanup. I'm surprised the camera can move the sensor and stabilize it so quickly.

I am also wondering about the succession of actions - the camera must try to figure out if the shake can be compensated to show the indicator, and then it must place the sensor into position and actually counter the shake when the shutter is fully pressed. Pretty amazing they can do this in a fraction of a second.

Still mysterious why the sound is better muffled on some cameras.
12-07-2011, 06:16 PM - 1 Like   #41
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Laurentiu,

I followed pentup's advice and emailed Pentax about the whirring. According to the reply I received, Gimbal, et al are correct about SR being the source. Here's the response:

QuoteQuote:
The “whirring” is a normal operational sound made by the Shake Reduction/sensor assembly and that the sound will be made whether Shake Reduction is on or off. The mirror mechanism will make an audible sound when the mirror is swung up and swung down, but again the “whirring” sound made when the mirror is in the up position is normal and associated with the Shake Reduction assembly.

There is an exploded view of the Shake Reduction assembly on our Web site, but it doesn’t explain how the assembly itself works. (The sensor is on a plate containing motion sensors and electromagnets. The plate rides on bearings between two other plates, one of which contains permanent magnets. When an exposure is made, the plate with the sensor is held in place by a balance of forces between the electromagnets and permanent magnets. If Shake Reduction is turned on, input from the motion sensors will be used to vary the pull of individual electromagnets and adjust the sensor position.


By the way, that reply came from a third party (Total Outsourced Systems Inc.). I suppose farming out such tasks is the norm...

QuoteOriginally posted by Laurentiu Cristofor Quote
...Still mysterious why the sound is better muffled on some cameras.
Both my K-7 and K10D make a noticeable whir when their mirrors are up.
For what it's worth, while digging around I found a thread where a Forums member asked about K20D noisy live view:
https://www.pentaxforums.com/forums/pentax-dslr-discussion/51485-liveview-audible-noise.html

Last edited by .a.t.; 12-07-2011 at 07:46 PM.
12-07-2011, 07:15 PM   #42
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QuoteOriginally posted by pentup Quote
And into pomposity and ingratitude.
12-07-2011, 10:05 PM   #43
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QuoteOriginally posted by jpzk Quote
Isn't it strange how people feel the need to contribute even when they don't have much to say on topic?
12-07-2011, 10:09 PM   #44
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Let it go folks. My remark, which jpzk is kindly smiling at, was gratuitous and and added nothing to the discussion -- much like the remark of yours that prompted it, Laurentiu.
12-07-2011, 10:09 PM   #45
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QuoteOriginally posted by all thumbs Quote
I followed pentup's advice and emailed Pentax about the whirring. According to the reply I received, Gimbal, et al are correct about SR being the source.
Thanks for the confirmation!

QuoteOriginally posted by all thumbs Quote
Both my K-7 and K10D make a noticeable whir when their mirrors are up.
Mine too. It's the K20D I found to be more silent.

QuoteOriginally posted by all thumbs Quote
For what it's worth, while digging around I found a thread where a Forums member asked about K20D noisy live view:
https://www.pentaxforums.com/forums/pentax-dslr-discussion/51485-liveview-audible-noise.html
Yes, there is an earlier post in this thread too, by Kunzite, that points this out. Seemks like there is some variation in the build of K20Ds.
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