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04-15-2012, 08:04 PM   #1
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K5 and DA*300/4 intermittent focus OOF/blurriness

Title typo error: K% = K5

My set up with the K5 and the DA*300/4 has always been very good in terms of AF acuracy.

Today, there seems to be some sort of intermittent problem with the final images, especially those taken at fair distances, say >50 feet or so.
This is usually not a problem at all, even in cases when I try to "over-reach" the target(s), but this is rather strange.

For instance, I can get good focus at near range ... less than 20 feet, then a repeat shot at the same distance results in OOF, or "blurriness".
Also, same in reverse: good AF at 50-100 feet then "blurriness" or OOF at the same distance.

Anyway, I am going to post some pics once I have them all processed.

What gets me is that the combo lens-camera is usually just fine but now it has shown some intermittent focusing "problems".
Weird thing is that this happened once before and just went away!

Back soon with pics.


JP

That will take some time because I tried the "old way" via "manage attachments" and it is making a mess. I will post them via Flickr as soon as I have the chance.


Last edited by jpzk; 04-15-2012 at 08:16 PM.
04-15-2012, 08:44 PM   #2
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is it focus or movement blur? Tripod or hand held? Is SR on? Shutter speed? I had some issues with SR where taking a shot before it initialized would show up as blur.
04-15-2012, 09:43 PM   #3
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I think I feel your pain. I have probably 1,000 outings on my da*300 and although I love it and give it hugs when I tuck it in at night, I am aware of its personality.
- if its been a rare time where it was not used for more than a few days it can be slow to AF or just not try the first time or two. So I always start my walk with a few horizon to my feet and back kind of shots to warm it up. It seems fine always after that.
- I keep it focused near infinity as it seems much happier and faster to acquire focus as it zooms in than if it was already set too close and has to zoom in, then out. Sometimes in those cases it stops after one try and I have a blinking icon in the viewfinder and nothing to shoot.
- It was probably only reliable %50 of the time when using a Tamron 1.4x Tz MC4 teleconverter so I dropped that.

Otherwise it seems to be aging gracefully but at no time have I ever felt the SDM motor was more than minimum power for it. Still, won't trade it unless it stops keeping up with the BIFs.

If any of this sounds familiar and you want more detail let me know.
04-15-2012, 09:53 PM   #4
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I hope for your that it is not the start of SDM failure. But your description tends to match a number of threads describing incoming SDM failure.....

Hope that you are still under warranty.

04-16-2012, 12:02 AM   #5
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Sdm failures on non-zoom lenses are very, very rare..
Take a look at the SDM survey made by PF.
04-16-2012, 12:52 AM   #6
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You might try cleaning all the contact pins between the lens and body, like the Pz contacts - just a thought.

I had a FA 50 act up at one point and cleaning the contacts solved the problem. Not sure if members have had similar problems with the Pz contacts.
04-16-2012, 07:21 AM   #7
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What do you mean by repeat shot.
My K5&me have trouble keeping the focus for any image sequence after the first one - that includes slight movements of the subject or the camera. I only do singkle shots and refocus for the next shot.
04-16-2012, 01:11 PM   #8
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maybe just a hick-up bu the combination.

04-16-2012, 01:43 PM   #9
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QuoteOriginally posted by derekkite Quote
is it focus or movement blur? Tripod or hand held? Is SR on? Shutter speed? I had some issues with SR where taking a shot before it initialized would show up as blur.
Focus ... definitely; no movement blur at 1/1250s
Hand held, as always.
Yes, SR was "ON" ... maybe that where the problem is, however, I tested that w/w-out SR: same thing.

Incidentally: the focus was bang on today ! , even with tiny birds at 50 feet +
04-16-2012, 01:49 PM   #10
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QuoteOriginally posted by imtheguy Quote
I think I feel your pain. I have probably 1,000 outings on my da*300 and although I love it and give it hugs when I tuck it in at night, I am aware of its personality.
- if its been a rare time where it was not used for more than a few days it can be slow to AF or just not try the first time or two. So I always start my walk with a few horizon to my feet and back kind of shots to warm it up. It seems fine always after that.
- I keep it focused near infinity as it seems much happier and faster to acquire focus as it zooms in than if it was already set too close and has to zoom in, then out. Sometimes in those cases it stops after one try and I have a blinking icon in the viewfinder and nothing to shoot.
- It was probably only reliable %50 of the time when using a Tamron 1.4x Tz MC4 teleconverter so I dropped that.

Otherwise it seems to be aging gracefully but at no time have I ever felt the SDM motor was more than minimum power for it. Still, won't trade it unless it stops keeping up with the BIFs.

If any of this sounds familiar and you want more detail let me know.
This seems to be the case indeed:

Today: I focused on close/distant subjects so the lens would actually "work" before taking aim to the wanted target and this seems to work.
Letting the lens "acquire" the target is the key I think.
Then as you said, I tried focusing on a target when I was "very close" to the wanted focus ... and it misbehaved again, intermitently.

This is not the type of SDM upcoming failure I experienced with the DA*16-50 (which was replaced - now I have a great copy).

It would be nice to know about your details ... it does sound very much like you said.

JP
04-16-2012, 01:50 PM   #11
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QuoteOriginally posted by hcc Quote
I hope for your that it is not the start of SDM failure. But your description tends to match a number of threads describing incoming SDM failure.....

Hope that you are still under warranty.
Nope ... I know what a SDM failure does, believe me.

JP
04-16-2012, 01:51 PM   #12
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QuoteOriginally posted by Couscousdelight Quote
Sdm failures on non-zoom lenses are very, very rare..
Take a look at the SDM survey made by PF.
Agreed; I had only one failure and it was with the DA*16-50.
This is a different matter altogether and I think imtheguy nailed it.

JP
04-16-2012, 01:52 PM   #13
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QuoteOriginally posted by philbaum Quote
You might try cleaning all the contact pins between the lens and body, like the Pz contacts - just a thought.

I had a FA 50 act up at one point and cleaning the contacts solved the problem. Not sure if members have had similar problems with the Pz contacts.
That couln't hurt to do it, right?

Thanks for the tip.

JP
04-16-2012, 01:53 PM   #14
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QuoteOriginally posted by zapp Quote
What do you mean by repeat shot.
My K5&me have trouble keeping the focus for any image sequence after the first one - that includes slight movements of the subject or the camera. I only do singkle shots and refocus for the next shot.
I said "repeat shots", not "continous".

JP
04-17-2012, 07:55 PM   #15
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AF area size is bigger than little red square wich is only a visual indicator of the AF area selected.

If several objects are in an AF area, focus is made on any object detected by the cross type AF sensor of the area. So focus may vary between two consecutive shots if there is some movement of the objects in the AF area selected. It's good to keep in mind. To get good focus, take care of complex subjects, for them select a secure Aperture with large DOF or try Liveview.

See https://www.pentaxforums.com/forums/pentax-k-5-forum/177572-all-fuss-about-au...oint-size.html

Last edited by pscl57; 04-17-2012 at 08:07 PM.
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