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K100D SR is Locked when Off

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SamJang

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Just in case those of you who care might have missed it in a previous thread, I'm reposting a bit of info I received from Pentax Tech service here:

I asked about the SR mechanism - whether it is locked when the camera is turned off or if it could potentially move around when the camera is shaken (while off) as mentioned in the October PopPhoto article. Below is a response from Pentax:

"Thank you for contacting Pentax.

The Shake Reduction mechanism which allows free movement of the CCD while in use does indeed lock it in place when the camera is powered off.

If you are in need of further assistance, please respond to this email or call our technical support center at 800-877-0155.

Sincerely,
Pentax Imaging Technical Support"

It resolved my concerns... I hope it answered other member's questions too.

Thanks
Sam
 
Interesting piece of info. Thanks for posting!

Wim

--
Belgium, GMT+1

 
Perhaps we can further probe on the locking mechanism clarification. I am interested to know whether the lock will remain if we remove the battery from the compartment

I assume the lock requires certain power source to enable thus w/o the batteries it should be totally disabled and start moving around.

--
William Tay
A proud owner of a ist DL with DA18-55, 50-200 and FA50/1.4.
 
--
William Tay
A proud owner of a ist DL with DA18-55, 50-200 and FA50/1.4.
 
You're welcome...

It was bugging me more than anything. I am "this" close (hold index finger and thumb close together) to jumping into the DSLR world and this issue was stopping me from getting the K100D. I'm no photographer in that I don't know how to take all the fantastic shots in this forum. I'm just looking for a camera I can rely on to take good pictures of my fast growing (and fast moving!) toddlers. I need all the help I can get and felt the SR feature would be great and until now I was agonizing whether I should spend the big bucks on a camera that might fail earlier than a almost equal but cheaper camera (K110D). But now that I know, I feel a whole lot better.

Thanks
Sam
 
While I can see where you are coming from about needing power to "lock" the sensor, I also think it would be a catastrophic lapse in judgment by Pentax if they allowed constant battery drain to keep the camera off. Imagine the uproar from users when they find that a fully charged battery became drained while being turned OFF! Also, by this logic, we would have to assume that turning the SR off when the camera is ON would also drain the battery which seem to go against the common consensus here that using SR would drain the battery more than not using it.

Thanks,
Sam
 
wtay said:
I assume the lock requires certain power source to enable thus w/o
the batteries it should be totally disabled and start moving around.
Click to expand...
I don't think so. As an engineer I would never design the system that way.

More likely "lock" is actually just a consequence of SR not working (camera being on or off does not matter): only when SR engages camera unlocks sensor plate, move it around to do SR compensation, and as soon as SR stops working sensor gets locked again.

This way default state is "locked", and power is required only to unlock for a brief period of time SR works. Also MUCH more power efficient.

That is the opposite of your assumption that sensor floats freely all the time and requires power to stay in place. That would drain batteries while camera if actually powered off!

-= Ivan =-
 
I can imagine that it is locked because some permanet magnets hold it in place when power is off and when power is on the electrmagnetic coils are what counteracts the permanent magnets and the energy sent to the coils is what causes the CCD to move and repel the force from the permanent magnets just as a loud speaker remains held in place by the permanent magnet and moves when the audio signal is applied.
 
The one thing I wonder about re: the SR being locked... The K100D has this weird sort of "shift" feeling when you turn it vertically in your hand that doesn't seem to just come from the batteries moving. I've never been able to figure out what it is, but I had previously assumed it was related to the SR apparatus.
 
selfnoise04101 said:
The one thing I wonder about re: the SR being locked... The K100D
has this weird sort of "shift" feeling when you turn it vertically
in your hand that doesn't seem to just come from the batteries
moving. I've never been able to figure out what it is, but I had
previously assumed it was related to the SR apparatus.
Click to expand...
Maybe it's a slight shift of the CCD suspended from the force of the permanent magnets I mentioned above. I can imagine it will shift when an external movement occurs.

I am constantly amazed at the speculation and worry that is posted in the forum about how equipment is designed.
 
hcoley said:
I can imagine that it is locked because some permanet magnets hold
it in place when power is off and when power is on the
electrmagnetic coils are what counteracts the permanent magnets and
the energy sent to the coils is what causes the CCD to move and
repel the force from the permanent magnets just as a loud speaker
remains held in place by the permanent magnet and moves when the
audio signal is applied.
Click to expand...
The SR fact sheet shows a diagram of a permanent magnet plate.
http://www.pentaxslr.com/files/scms_docs//PENTAX_SR_Description_091506.pdf

The electromagnetic coils can bee seen in this photo.



Obviously the CCD plate is held firm by the permanent magnets and then moved when a signal is applied to the electromagnetic coils to repel the force of the magnets.
 
I believe the actual "floating mechanism" is only "hot" when the shutter button is pressed, any other time it is rock solid! The on/off switch kills power to the EMs and thus power when the shutter button is depressed.
 
You feel the slight shift because the mechnism is not mechanically locked (the response from Pentax in the original post was incorrect). There is no mechanical locking system in the camera. However, Pentax engineers have thoroughly tested the system, working with the CCD manufacturer, to assure that this system will not be damaged or cause extra wear during the life of the camera.
--
John C.
 
SamJang said:
While I can see where you are coming from about needing power to
"lock" the sensor, I also think it would be a catastrophic lapse in
judgment by Pentax if they allowed constant battery drain to keep
the camera off. Imagine the uproar from users when they find that a
fully charged battery became drained while being turned OFF!
Click to expand...
On the other hand, some of the Nikon cameras that I've seen (D50 and D70) use an LCD overlaying the VF to display gridlines. If the battery is removed (or runs right down) the view through the VF suddenly becomes incredibly murky (really put me off the Nikon when I first saw it in shops without a battery), which seems to indicate that power is being used for the LCD even when the camera is turned off.

Nobody really complains about that -- probably not much power is required.
SamJang said:
Also,
by this logic, we would have to assume that turning the SR off when
the camera is ON would also drain the battery which seem to go
against the common consensus here that using SR would drain the
battery more than not using it.
Click to expand...
It almost certainly draws power when taking a photo with SR off -- it still has to move the sensor to the centre of the image circle; I'm guessing that whatever locking mechanism they use is likely to hold the sensor at one extreme rather than in the dead centre...

And then we still need confirmation of this issue -- what was the rattling noticed in the article that started these concerns, if not the sensor moving?

Pete

--
http://www.magpiementality.org/gallery
 
Seems it uses permanent magnets to hold it against the container at the front (from a post below). So the sensor might be held in the centre when it (or SR) is off...

Still need to know what was moving around in the review though. Perhaps the permanent magnet isn't strong enough for the shaking they were doing at the time?

Pete

--
http://www.magpiementality.org/gallery
 
pjv said:
Seems it uses permanent magnets to hold it against the container at
the front (from a post below). So the sensor might be held in the
centre when it (or SR) is off...
Click to expand...
From the same document [1]:

"Does battery life change while the SR system is engaged?
No, battery life remains the same whether the SR system is turned on or off."

So it probably does still move the sensor with SR off:

It also appears that previous claims about compensating for rotational shake caused by pressing the shutter may have been false. It appears to move the sensor only on two axis', and both at once:

"Based on a free-floating sensor design, PENTAX SR is superior to other sensor-moving systems because it uses no guide rails, allowing the sensor to oscillate in three directions—horizontally, vertically, and diagonally"

Pete

[1] http://www.pentaxslr.com/files/scms_docs//PENTAX_SR_Description_091506.pdf
--
http://www.magpiementality.org/gallery
 
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