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09-14-2009, 03:55 AM   #16
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If I'm guessing right, the SR system is some sort of adaptive servo loop system, which makes sense since it need some time with the shutter half pressed before it starts to work properly. Servo loops like this is very hard to get robust, and there are lots of opportunities for oscillations and saturation. Or maybe the system fails to lock fast enough in certain conditions that the designers at Pentax did not predict.

Anyway, if this is a real problem, and Pentax acknowledge it, it should be fixable through firmware.

09-14-2009, 04:09 AM   #17
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I have updated to 1.01 firmware and was not able to reproduce the problem so far. Let's keep fingers crossed and hope it's not just coincidence.
09-19-2009, 02:34 PM   #18
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Unfortunately it was just coincidence. SR still occationately blurs fast shutter speed pictures
11-29-2009, 09:48 AM   #19
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QuoteOriginally posted by Edvinas Quote
Last hour I've taken about 100 pictures with K-7 + DA 16-45mm with various shutter speeds and here's what I've noticed:
  • 1/180s seems like worst shutter speed for SR, slower and faster shutter does not produce such blur.
  • SR blur isn't consistent. There can be five perfectly sharp pictures and then something happens and SR blurs a few pictures.
  • In slow shutter sutuations when I need to get 2-3 additional stops SR works. Not 100%, but works. It looks really weird when SR manages to get tack sharp picture at 1/10 sec (45mm focal length) however blurs picture taken at 1/180 sec.
Anyway, from now on I will keep SR turned off and will turn it on only when I really need it.
Your solution, to turn SR off most of the time, is the best workaround for now, I suppose. But, in my mind, it's ABSOLUTELY UNACCEPTABLE that this issue exists. I have the same problem with my K-7, and I'm quite disappointed (to put it mildly), as one of the reasons I made the switch from Canon to Pentax was because of in-camera SR. So now I have a camera that not only has ineffective SR, but one where you basically need to turn SR off to avoid blurry pictures. And I don't have the option to get in-lens IS, as Pentax doesn't do that.

I sent my camera in to get this problem fixed, so I really hope things will work out...

11-29-2009, 10:03 AM   #20
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I have my k20d set to jump shutter speeds in 1/3 stop increments. It can be set to 1/160 and 1/200 but no way to set it to 1/180 unless in X-sync mode.

I agree that 1/180th and SR issues seem connected as I have seen other threads asking about this.

Maybe the camera assumes that if you got 1/180th, you must be in X-sync mode and using a strobe of some sort? It assumes the strobe will stop the action and somehow it messes up the SR in the process.
11-29-2009, 01:08 PM   #21
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QuoteOriginally posted by joshnl Quote
So now I have a camera that not only has ineffective SR, but one where you basically need to turn SR off to avoid blurry pictures.
Maybe you have a defective camera. That happens all the time with every brand.

If your camera is OK, you are exaggerating a lot. The Pentax SR has been tested and proven to work many times. It remains to be seen if it is (perhaps purposefully) less effective at 1/180 but there is absolutely no doubt that it is of tremendous value at slower shutter speeds.

QuoteOriginally posted by enoeske Quote
I agree that 1/180th and SR issues seem connected as I have seen other threads asking about this.
I did a search and only found this " SR Disabled in Wireless Flash Mode?" thread where a user reports SR being disabled in a particular (wireless flash) mode.
Could you please post links to the threads you mentioned?

Last edited by Class A; 11-29-2009 at 01:34 PM.
11-29-2009, 01:35 PM   #22
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QuoteOriginally posted by Edvinas Quote
I have updated to 1.01 firmware and was not able to reproduce the problem so far. Let's keep fingers crossed and hope it's not just coincidence.
the EXIF data on the OP shots say that the camera has firmware v1.00

Update and try again.

Edit: didn't see that one above me. Seems to be working then?
11-29-2009, 01:51 PM   #23
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QuoteOriginally posted by joshnl Quote
I sent my camera in to get this problem fixed, so I really hope things will work out...
I also had this situation, however mine was just bad at all speeds. Sent the camera in a month ago, and have learned that a SR Block Assembly is on order to correct the condition. It's like any new product being mass produced, there is a factor of the units that aren't right straight out of the box. The tough part is spending a small fortune only to have the camera in the shop for weeks on end.

11-29-2009, 01:54 PM   #24
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QuoteOriginally posted by Class A Quote
Could you please post links to the threads you mentioned?
Here's one
https://www.pentaxforums.com/forums/pentax-dslr-discussion/68202-pentax-k-7-s...n-problem.html
11-29-2009, 02:58 PM   #25
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I was thinking about a connection between ineffective SR and 1/180 shutter speed. There is no such connection in this thread.

Also, note that the OP had a defective camera and got it replaced. Since then he has been happy.
11-29-2009, 09:17 PM   #26
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QuoteOriginally posted by Class A Quote
I was thinking about a connection between ineffective SR and 1/180 shutter speed.
I've had one case where I was using flash (540) semi-outside (taking picture of the schools canteen manager for yearbook... she was behind counter inside canteen, I was wanting to include "her window" in the scene which was much brighter than her indoor lighting). Haven't got the files here but pretty sure it was 1/180th sec. I was fudging the FEC to balance the light on her and when reviewing the pics on the LCD could see none were sharp. Eventually decided that since it was only going to be a 2" wide pic in the book it would have to do! Looking at it full-size there's a distinct 2nd 'ghosted' image. Will need to post the actual pic to show.

Nige.
11-30-2009, 01:15 AM   #27
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Edvinas, I have noticed similar problem with my K10D and SR. Not at 1/180 shutter speed, but the problem seems very similar to yours - SR is not helping, but actually making things worse. We had a familly meeting, and I did some portraits. I used tamron 17-50 f2.8. I noticed the problem with one of my sisters and her husband, I just couldn't make sharp picture of them. With all previous and next shots everything was ok. Later I tried to analyze what I did differently with these particular shots. My conclusion is that I didn't wait long enough to steady the SR mechanisam. Although I had the signal in my viewfinder that SR is ON, it seems that this indicator showed up to early in this particural situation - I had to focus to her dress (I use only center AF point), and after AF confirmation I quickly moved the camera to the right position. This quick move somehow confused SR. Afterwards I did experiment with this quick movement to find out what I did wrong, and it seems that I moved the camera to quickly, so that SR did not calm enough. The solution I found is that I just had to wait another second or two and then take a shot. This would steady SR sensor before it should decide how to compensate my hand shake. All of my shots were taken at 1/40.
11-30-2009, 05:25 AM   #28
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here's my example

full pic, resized


100% crop


Notice how it has a distinct secondary image (easiest to see where it says 'School Straps') but it's not blurred like you'd expect camera shake would look like. I haven't noticed this in any other pics since but if I encounter it again I'll try turning 'shake reduction' off!
11-30-2009, 01:45 PM   #29
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QuoteOriginally posted by HGMonaro Quote
here's my example...
At that focal length (26mm) and shutter speed (1/100) there should not have been blur even without shake reduction unless you jerked the camera around big time.

The image resembles a multi-flash exposure. It almost looks like that one (ghost) image resulted from a pre-flash and the other from the real flash. If the weaker image had been created by the ambient light one would expect movement blur, unless perhaps the sensor stayed at one position most of the time and then moved increadibly fast to a second one.

I've never seen anything like it.
11-30-2009, 04:17 PM   #30
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thanks for those comments... never even thought the flash could be the culprit but what you describe makes more sense than anything else!
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