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12-07-2011, 10:12 PM   #46
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QuoteOriginally posted by pentup Quote
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.
And much like this one too.

12-07-2011, 11:25 PM   #47
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Thread digest

This is a digest of the more useful information brought up so far on the question of what causes the whirring noise in LiveView and possible reasons that would explain why a K20D I handled was pretty much silent in this respect:

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.
QuoteOriginally posted by Laurentiu Cristofor Quote
The difference I noticed was striking, not at all a matter of "now you hear it, now you don't". My friend and I have both been away last week but I'll check with him to see if his camera is also silent when the mirror is lifted up for cleaning.

SR makes no noise during regular use, so why would it make noise during LiveView? You can just press the shutter half way to activate the SR indicator in the viewfinder and listen to the camera while keeping SR activated - it's completely silent. Go into LiveView and you suddenly have the same noise that the camera makes when you lift the mirror up.

The noise the camera makes was the main reason I didn't warm up to the LiveView feature and I used it only sparingly - I always felt the camera is making some effort to sustain the feature and it may break at any point - I just didn't feel comfortable using it like that. So, obviously, I've been surprised to find that an older model that supposedly had an inferior implementation of LiveView, actually worked better.
QuoteOriginally posted by Gimbal Quote
That's because the servo motors that lift/control the sensor plate (and cause the noise) isn't engaged (even though the SR icon is lit) until they are actually needed. And they are not needed when the shutter is closed. But when the shutter is open, they are engaged, even if SR is off, thus the sound can be heard during long exposures, video, live view or sensor cleaning.
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
QuoteOriginally posted by Gimbal Quote
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.
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.
QuoteOriginally posted by Gimbal Quote
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).
QuoteOriginally posted by all thumbs Quote
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.
[/COLOR]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
Thanks again to those that tried to help. Just because I didn't quote your post above doesn't mean you are excluded from my thanks.
04-07-2012, 10:54 AM   #48
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I noticed today that my K20D made the whirring sound during live view. This thread was the result of my search for an answer. As mentioned above, I turned off shake reduction and the noise went away. So it is caused by the sensor hunting during live view. The K20D does this also. So the K20D mentioned by the OP must have had the shake reduction turned off. Thanks for the help.
04-08-2012, 09:52 PM   #49
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QuoteOriginally posted by Big Dave Quote
So the K20D mentioned by the OP must have had the shake reduction turned off. Thanks for the help.
No. It had it on. There was noise too, but you had to listen to it very carefully in a silent environment. The K-7/K-x make sounds that are much easier to notice than the K20D.

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