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06-14-2008, 05:18 PM   #1
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SR problem on K20D

Hello,
last week I tried to shoot Moon with old mirror 500/8 lens, so I also manually set focal length 500. The result was better than I expected. However, next day, when I did some tests with normal DA18-55 lens, I noticed that pictures taken with SR ON are worse than with SR OFF ! It seems to me that there is a bug in firmware that causes wrong FL is used for SR, i.e. FL of the last manually entered value, instead of actual FL of DA lens.
The behaviour is consistently reproducible - put manual lens and set FL e.g. 50, than put DA lens and set SR ON - the pictures will be better than with SR OFF.
Then put manual lens and set FL e.g. 500, than put DA lens and set SR ON - the pictures will be more blurry than with SR OFF !
(However, the Live View is not affected, i.e. it is always correctly stabilized with DA lens)

06-14-2008, 05:53 PM   #2
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Interesting observations. Have you forwarded your findings to Pentax?
06-14-2008, 06:15 PM   #3
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Maybe the S.R. doesn't reset itself to the new lens by itself after you take off the manual lens. That would explain the blurred photos. Did you try cleaning the contact on your automatic lenses and on the camera? There might be some build-up on the contact preventeng a good contact.
06-15-2008, 12:00 AM   #4
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Is the mirror still up?. I saw someting in the owners manual regarding this.

06-15-2008, 09:38 AM   #5
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Is there a "memory" option in the K20D that remembers the SR settings of the lasted entered value, instead of "auto" ?

Perhaps this is the culprit? Wish I had a K20D to test this on
06-15-2008, 09:52 AM   #6
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Are you using a tripod ?

My guess is that you are.

If so - SR should be turned off.
06-15-2008, 09:55 AM   #7
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You sure got me wondering now, my softness often looked like shake, so i blamed myself not waiting for the shake sign to come on, paid more attention to it and still softness, looking right now, SR is still on 135 from the S-M-C 135/3.5.

cputeq: Memory in menu does not include SR, but it does store the last used FL on a manual lens. Would be nice if EXIF recorded the SR FL used wth any given length, which should of course match the FL the DA lens was set to.

Edit: As much as i would have loved to say it is obvious and confirmable, taking off the lens, changing Input Focal Length and remounting the lens (DA* 16-50) does not seem to change the results. I switched between 50mm and 500mm to make it obvious if there was a bug, curious person i am i will try this on near infinity shots again anyways. I shot 1/30 at 50mm to be in a SR range, and albeit i could handhold 1/30 very possibly, we talk about SR affecting it negatively, so i think 1/30 would be a good value.
I only tested SR on (50mm) vs SR on (500mm), which per OP's description should be very noticably different.
Perhaps the bug is not in the K20D but in the FL reporting of the DA 18-55? Or a combination of both.

Last edited by morfic; 06-15-2008 at 10:14 AM.
06-15-2008, 04:20 PM   #8
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QuoteOriginally posted by ivanp Quote
The behaviour is consistently reproducible - [...]
Then put manual lens and set FL e.g. 500, than put DA lens and set SR ON - the pictures will be more blurry than with SR OFF !
ivanp, this may be turned into a feature if explored further!

Maybe, using a manual lens, dialing in, e.g., 420mm, and then a 1.4x teleconverter with DA 300mm lens eventually allows to combine a teleconverter with SR!

Any way to test this out?

06-16-2008, 07:40 AM   #9
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Are you turning the camera off with the switch, or letting the timer turn it off? If I turn mine off with the switch and change MF lenses it will ask for focal length input when I turn it on. If I just let it time out, it doesn't ask, it retains the setting from the previous lens.
06-16-2008, 09:52 AM   #10
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QuoteOriginally posted by Parallax Quote
Are you turning the camera off with the switch, or letting the timer turn it off? If I turn mine off with the switch and change MF lenses it will ask for focal length input when I turn it on. If I just let it time out, it doesn't ask, it retains the setting from the previous lens.
That's fine, and if he would notice incorrect SR on only MF lenses we may have found why he gets his results, however he talks about switching between an MF lens and a DA lens, in which case, the electronics should listen to the reported focal length of the DA lens......timed out or turned on/off.
06-16-2008, 10:41 AM   #11
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May I repeat and update my question?

Is it true that SR may work with a DA lens and a focal length as entered manually before the DA lens was mounted?

W/o any lens mounted, when you switch the body on, you are able to enter a focal length, say A. Now mount the DA lens with focal length, say B. Does it use A if the lens was mounted hot, or in stand-by?

I found a way to actually find it out:

PhotoME reports two focal lengths for RAW EXIFs:
- One in the generic section.
- Another one in the vendor section, as ShakeReductionInfo[3].

So, it would be great news if it were possible to make both values differ (a bug turned into feature).


(Note: I would try it out myself -- but my K20D is sent to Pentax for a grip replacement )
06-16-2008, 11:52 AM   #12
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Dialed in 500mm, remounted lens, shot, 50mm, SR FL 48mm, that's on a 16-50 at 50mm, i keep seeing that 48mm a lot, it escapes me what it was that also reported 48mm.


This was w/o turning camera off in between

Addition: And the same when turning cam off and on again. The 500mm is never changed.

Edit: I never shot with the 500mm dialed in before remounting the 16-50
Edit2: Even after firing a stabilized shot at 500mm and remounting the 16-50, i get SR FL 48mm

Unless it is the kit lens doing/causing something wonky, there is no free feature to be had it seems.

P.S. i do like the first SR comment, i saw stabilized so i tried waking up the cam and shooting and sure enough the way i shoot when walking around in city, i could get a "not ready", so i will investigate now if the shaky looking shots were SR "not ready", then this thread was at least good for something, and i'll make sure to pimp PhotoME some more

Last edited by morfic; 06-16-2008 at 12:04 PM.
06-17-2008, 02:39 AM   #13
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QuoteOriginally posted by morfic Quote
Dialed in 500mm, remounted lens, shot, 50mm, SR FL 48mm [...] i'll make sure to pimp PhotoME some more
Yeah, I was positively surprised as well that SR ready and SR FL are actually in the EXIF

There may be just one final test missing before we can close this issue ...

Dial in focal length (e.g., w/o a lens), let the camera go in stand-by, then do stealth mount of a DA and shoot w/o switching off, i.e., by just awaking it by the half press, wait for SR, shoot.

What SR FL is in the EXIF then?
06-18-2008, 04:11 AM   #14
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Well, I am perplexed. I tested the behaviour I described in the first post many times - I switched manual FL back and forth at least 15 x, and the problem emerged consistently. Between those switching I always turned the camera off, and before fully pressing the shutter switch I always waited to Hand symbol in viewfinder.
Today I wanted to do more testing (to closly analyze exif info), and ... the problem just disappeared, everything works normally as expected!
The only explanation I have is that firmware got a bit mad, but that it was reset when I removed the battery to charge it. Many problems with PC software can be "solved" by resetting computer And just turning off the camera was not enough - even in Off position it still works - it can save data to SD card, or it can continue to shoot dark frame for NR.

I also did another test - I mounted A50/1.7 lens (i.e. manual, non digital), and take some pictures with FL set to 50, and then with FL set to 500. The picures taken with incorrect 500 FL was totally blurred, it was not the kind of picture degradation I originally observed.

Anyway, K20D is great !!!
06-18-2008, 05:19 AM   #15
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Could this simply be a low battery issue (you mentioned charging the battery). I know my *istD and K10D can both do some odd things when the battery is getting low. Another thing that can correct odd issues is resetting the camera.
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