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11-04-2008, 07:07 PM   #16
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QuoteOriginally posted by pixelpruner Quote
I think the SR uses an induced magnetic field to hold the sensor in place... so if the camera is off nothing holds it in place (well, obviously it's movement is limited!).
That's the right answer. The sensor can move freely and you hear it moving within the camera if you move the camera in certain ways.

That's why turning SR off, won't save you any noticeable battery life, because even when it is off, the sensor is held in place by electromagnetic fields (which need power to be generated).

11-04-2008, 07:14 PM   #17
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QuoteOriginally posted by pixelpruner Quote
Same thing on my K10D. It freaked me a bit when i first got it but I guessed it was the SR.

I think the SR uses an induced magnetic field to hold the sensor in place... so if the camera is off nothing holds it in place (well, obviously it's movement is limited!). Not sure if that's how it works, just a guess.
Makes sense, but why does it do the thunk when it is turned from portrait to landscape position? Almost as though the sensor is being reoriented?.

Aha, woodworm says earlier...
QuoteQuote:
My K10D does that and it's perfectly normal - I was lead to believe that it's the orientation sensor.

The camera knows when it's being held in either landscape or portrait - you will notice you don't have to rotate your images when viewing them.
Could this be it then, the sensor 'flops' between modes as the camera is turned.Then at the time of taking the shot the electromagnets actuate and lock it in place.
Would explain why it happens with the camera both off and on.
Note to self.. will go and try turning the camera during a long exposure and see if it thunks.

Any comments?.
11-05-2008, 12:26 AM   #18
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QuoteOriginally posted by bobD Quote
.
Forgive my newcomers ignorance. I thought the SR system was an active one so how can it clunk when not powered up and no batteries?
I don't know what you mean by "active" here. The sensor is basically loose in its slots and free to slie around at all times, which is why it clunks when rotting or shaking the camera even when turned off. Only when turned *on* does the mechanism hold the sensor steady.

Trust me, virtually *everyone* who has ever bought a Pentax camera with SR asks abut this. There have been hundreds of posts asking this very question over the last several years. It's SR, not even the slightest doubt about it.
11-05-2008, 01:25 AM   #19
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QuoteOriginally posted by bobD Quote
So you have the same noise/vibration?
From new out of the box?
With or without batteries in, or lens on/off?

More info would be helpful in my decision as to purchasing this camera. Thank you.
If I rotate the camera that noise is there, with or without batteries, still the same. As others stated here already I think there is nothing to worry about.

11-05-2008, 01:48 AM   #20
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First off, this has been discussed ever since the K100D was introduced in 2006. There is nothing wrong with the camera.

Go to this web page and click on the links on the page for a detailed explanation of Pentax's Shake Reduction.

Pentax Imaging - Pentax Press Release
11-05-2008, 02:17 AM   #21
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Thanks everyone.
I am feeling more confidant about this camera and you have pointed me in the right direction.
I followed up the Shake Reduction information and found this....

www.pentaximaging.com/files/scms_docs/SHAKE_REDUCTION_FACT_SHEET.pdf -

Now that I see the mechanism involved I can understand the movement and thus the noise it will make.

I do think that the manual should say something about it and note that it is normal.
Otherwise it feels like it is broken straight out of the box.

There are probably degrees of clunk varying with different samples and perhaps I just have a particularly clunky one. I will check with the importer/agent tomorrow.

Having worked through that I have to say on the up side that I have just tried my old bellows and a super-takumar 1:3.5/135 to take some shots of finger rings and I am well pleased.
Someone here suggested the smallest extension ring between the bellows and body to aid fit and clearance.This was a great idea

Used the self timer to lock the mirror up and reduce shake.

I am really looking forward to experimenting more!

Thanks to all, once again.
11-05-2008, 04:07 AM   #22
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I always thought the clunk was the orientation sensor.
If it is the SR system. I find it strange that when holding the shutter button halfway to maintain SR, my camera (k10d) will still clunk when I tilt it over. Surely SR keeps the sensor roughly in one place by means of its electromagents, and wouldn't let it tip over again..?
SR does work properly on my camera, so I'm ruling out a fault.
11-05-2008, 04:20 AM   #23
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QuoteOriginally posted by Spongefingers Quote
I find it strange that when holding the shutter button halfway to maintain SR, my camera (k10d) will still clunk when I tilt it over.
This is because pressing the shutter button halfway doesn't cause the sensor to be kept in place yet.

Select "bulb mode" press the shutter button and keep it pressed. Now move the camera around. There shouldn't be any clunking sound now (at least not on a K100D which has no orientation sensor ). Instead you'll hear a whirring sound which is caused by the sensor being held in place by the electromagnets.

11-05-2008, 04:30 AM   #24
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QuoteOriginally posted by Class A Quote
This is because pressing the shutter button halfway doesn't cause the sensor to be kept in place yet.

Select "bulb mode" press the shutter button and keep it pressed. Now move the camera around. There shouldn't be any clunking sound now (at least not on a K100D which has no orientation sensor ). Instead you'll hear a whirring sound which is caused by the sensor being held in place by the electromagnets.
My goodness, you're right!
It's not often I use bulb mode, the last time was when shooting some fireworks on the weekend. That was a noisy affair, as you can imagine. But I tried what you suggested in a quiet room, and I noticed the noise the SR makes on a long exposure - a nasty rumbling, scraping kind of noise. Quite unpleasant. No clunking, though, as you said.

I wonder if the Sony A900 sounds even worse?
11-05-2008, 04:51 AM   #25
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I'm still not convinced its the SR or tilt sensor on the K200D

A tilt sensor can be a very simple electrical device like a mercury switch. It doesn't have to be large and therefore heavy enough to thunk. Even my old P&S Canon A75 had a tilt sensor, and it didn't thunk.

The SR should by definition not thunk. Its a bunch of electromagnets that can move the sensor around. Class A's description of the sound and SpongeFingers comment support this.

Its really a matter of elimination.

With my K200D I took off my lense (18-55) and put on the caps (keep that nasty dust out ), removed the batteries and rotated the camera from horizontal to vertical (ie just the body). Couldn't really hear a sound - there was a faint sound, but it turned out to be strap hitting the body.

Added the batteries and tried again....there was very faint thunk turning anti-clockwise, and louder if turned clockwise.

Added the lens instead (batteries out) - now the thunk (slightly louder than the batteries) was there, but in both directions.

So there you go - at least in my case it the 18-55mm AL II lens - there appears to be some slap from the lens that makes the bulk of the noise.

Try it out with your camera as well and see what you get.

Cheers
11-05-2008, 05:50 AM   #26
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I haven't experienced this one either of my K200D bodies. Then again, neither one of them came with the lit lens.
11-05-2008, 07:24 AM   #27
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These cameras have no "tilt sensors" per se, they have two (or even three) axis accelerometers to detect camera shake to be compensated. These are incredibly precise yet tiny all-electronic chips. Since they also detect the acceleration due to gravity they double as tilt sensors for picture rotation.
11-05-2008, 11:37 AM   #28
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QuoteOriginally posted by MoiVous Quote
A tilt sensor can be a very simple electrical device like a mercury switch. It doesn't have to be large and therefore heavy enough to thunk.
You are correct here.

QuoteQuote:
The SR should by definition not thunk. Its a bunch of electromagnets that can move the sensor around.
This not correct. The sensor moves freely *until* it is held in place (and then mvoed *carefully*) by the electromagnets. This really isn't an open question - this has been well-known and described in detail in these forums ever since the K100D first came out over two years ago. SR definitely results in the sensor clunking around while it is not being held in place.

Which isn't to say there can't be *other* sources of clunking, like batteries or lenses or straps. But there is absolutely no question that SR causes a clunk too.
11-05-2008, 12:03 PM   #29
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QuoteOriginally posted by MoiVous Quote
With my K200D I took off my lense (18-55) and put on the caps (keep that nasty dust out ), removed the batteries and rotated the camera from horizontal to vertical (ie just the body). Couldn't really hear a sound - there was a faint sound, but it turned out to be strap hitting the body.
With my K200D, no lens,no batteries and held at arms length and turned I hear and feel a thunk.
11-05-2008, 12:22 PM   #30
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My K100 and K200 both do this, I'd assumed it was the SR (as with the K10) and haven't worried about it. Doesn't cause any problems.

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