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09-17-2009, 04:28 PM   #16
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As much as there is no better data out there we can access, this poll is unfortunately prone to selection bias, rendering the results quite misleading. Then you also have the possibility of incorrect reporting - failure reports may not actually be SDM failures, only the users haven't picked up on that.

Nevertheless, I don't discount that the SDM mechanism needs more perfecting - it's one of the major Achilles' heels of Pentax gear. Faster, more reliable and more robust...

09-17-2009, 07:07 PM   #17
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QuoteOriginally posted by deadwolfbones Quote
Should mention that it's not only Pentax who are having problems with HSM/SDM/USM motors. Sigma also has a huge issue with some of their lenses.
I apologize for the absence on the forums for the last few days, and not answering the legitimate call for support for my stats before now. I've been working on insulating a 3'6" (about a meter) high section of the basement, including constructing the wall to hold the bats.

Canon has some extremely unhappy lens owners on DPReview and other sites. I restricted my Googling to "lens" failures, and some very expensive Canon glass made some Canon owners just as angry as the DA* 16-50 and 50-135 owners who received faulty lenses.

And frankly, although I received good copies, I would have been just as angry if I had received a decentered 16-50. I'm holding my breath on the 50-135 - it's showing some of the symptoms, but contact cleaning has worked so far. I'm trying to hold out as long as possible during the warranty period.
09-17-2009, 08:29 PM   #18
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QuoteOriginally posted by Canada_Rockies Quote
I'm holding my breath on the 50-135 - it's showing some of the symptoms, but contact cleaning has worked so far. I'm trying to hold out as long as possible during the warranty period.
Al,
Sorry to hear that. That is exactly how it started on my 50-135. I believe the cleaning contacts is a placebo. It is an intermittent problem that comes and goes at first. And then slowly gets worse with time. The process of taking the lens off and putting it back on jars the motor back to life and it works again until you let it sit and want to use it again another day. It probably would have come back to life if you simply spun the focus ring back and forth. Make sure you don't let it go out of warranty if it in any way is behaving that way. Mine very slowly worsened until literally a day before the warranty period was over, I sent it to Pentax. They said the SDM motor system was faulty and sent me a new lens. It was obvious to me, that they have seen this many times before.

Last edited by PentaxPoke; 09-17-2009 at 08:36 PM.
09-18-2009, 10:10 AM   #19
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QuoteOriginally posted by PentaxPoke Quote
Al,
Sorry to hear that. That is exactly how it started on my 50-135. I believe the cleaning contacts is a placebo. It is an intermittent problem that comes and goes at first. And then slowly gets worse with time. The process of taking the lens off and putting it back on jars the motor back to life and it works again until you let it sit and want to use it again another day. It probably would have come back to life if you simply spun the focus ring back and forth. Make sure you don't let it go out of warranty if it in any way is behaving that way. Mine very slowly worsened until literally a day before the warranty period was over, I sent it to Pentax. They said the SDM motor system was faulty and sent me a new lens. It was obvious to me, that they have seen this many times before.
Thanks for the tip. We have a two year warranty period here in Canada, so I have some time yet. I think I will probably send it in in the spring, when my focus (pun intended) is on the 400 rather than the ice rink.

09-18-2009, 02:06 PM   #20
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The question is: Does the fact that the newer model lenses have fewer reported failures merely indicate that they have not yet had time to fail, or also that the SDM system is becoming more reliable as Pentax manufacturing and quality control processes improve and become more stable for the new technology? Time will tell, I suppose. I would expect reliability to gradually improve at least some though.
09-18-2009, 03:06 PM   #21
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PentaxPoke:
>. I believe the cleaning contacts is a placebo.
>It is an intermittent problem that comes and goes at first.
>And then slowly gets worse with time.
>The process of taking the lens off and putting it back on jars the motor back to life
>and it works again until you let it sit and want to use it again another day.

Exactly my situation!
And, my lens is not (practically) covered by warranty.
Now, I really do need a way to make the screw driven focusing system operate.
It is within the lens and apparently operational!
For some reason that entirely escapes me, I am not allowed to use it!
Oh, come on, Pentax!
09-18-2009, 03:46 PM   #22
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QuoteOriginally posted by bc_the_path Quote
PentaxPoke:
>. I believe the cleaning contacts is a placebo.
>It is an intermittent problem that comes and goes at first.
>And then slowly gets worse with time.
>The process of taking the lens off and putting it back on jars the motor back to life
>and it works again until you let it sit and want to use it again another day.

Exactly my situation!
And, my lens is not (practically) covered by warranty.
Now, I really do need a way to make the screw driven focusing system operate.
It is within the lens and apparently operational!
For some reason that entirely escapes me, I am not allowed to use it!
Oh, come on, Pentax!
If you are using a K10d, revert the lens to 1.20 firmware. I believe that the SDM update was in 1.30. Of course, all your SDM lenses will now function only with the screw drive, and the 17-70, if you have it, will be manual focus.
09-18-2009, 09:01 PM   #23
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QuoteOriginally posted by bc_the_path Quote
Exactly my situation!
And, my lens is not (practically) covered by warranty.
Now, I really do need a way to make the screw driven focusing system operate.
It is within the lens and apparently operational!
For some reason that entirely escapes me, I am not allowed to use it!
Oh, come on, Pentax!
I'm just wondering if you can just tape off the SDM contacts
If it works some nail polish on the lenses contacts might just do the trick for you.

09-18-2009, 10:05 PM   #24
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QuoteOriginally posted by little laker Quote
I'm just wondering if you can just tape off the SDM contacts
If it works some nail polish on the lenses contacts might just do the trick for you.
NO! This does not work. Has been suggested many times in many threads, in many forums. Fails every time.
09-19-2009, 06:39 PM   #25
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Unfortunately, the SDM in my DA 16-50 just failed. Quite frustrating. You could manual focus just fine, but SDM motors couldn't actually move the elements. Lens is only 6 months old. I am sending it in, but you have to think that Pentax will figure something out. Lenses that cost 700 or 800 dollars have got to have more durability than a couple of years.
09-20-2009, 10:37 PM   #26
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Add another 16-50 SDM failure to the tally. I purchased a 2nd hand 16-50 where the AF worked fine on the *istDS but would not work on the K200D. Lens reeturned for refund from buyer.
09-21-2009, 02:06 AM   #27
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Sad to hear all the 16-50 failures coming out of the woodworks.
Indeed this is my bone of contention for Pentax.
SDM development should be made a priority, not only for improving AF speed, but also in robustness.
09-21-2009, 07:57 AM   #28
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QuoteOriginally posted by pat_123 Quote
Add another 16-50 SDM failure to the tally. I purchased a 2nd hand 16-50 where the AF worked fine on the *istDS but would not work on the K200D. Lens reeturned for refund from buyer.
So maybe this is a K200d issue?
09-21-2009, 07:21 PM   #29
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QuoteOriginally posted by emr Quote
Those statistics DO NOT look good even if there's a bias! I've been pondering for months whether to buy a DA* zoom or not. I think this was the last straw for me.

Any direct link to the source? Or is it a verboten source?

EDIT: OK, found it with Google. A poll of yours, it seems.
The info is from this thread :
Re: so the 16-50 is the worst...: Pentax SLR Talk Forum: Digital Photography Review

And there was a discussion of it here :
SDM - maybe a precautionary application for use? [Page 1]: Pentax SLR Talk Forum: Digital Photography Review


It seems the early dual-shaft zooms, are the ones with most havoc.
Now that Pentax are creating SDM only lenses, it should leave room for more powerful motors.
Primes are generally more robust than zooms, so after some contemplating; Im leaning towards some DA* offerings that Ive been considering some time. I'm happy we've had the discussion, as it narrowed down a closer look at the issues.
I do expect well see updated versions of the DA* zooms, at some point.

Edit : And as stated in the manual, always turn off your camera before changing lenses. It seems the DA* might be more prone to error, than screw-drive.

Last edited by Jonson PL; 09-22-2009 at 01:06 AM.
09-21-2009, 08:24 PM   #30
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"plastic part" LOL :-)

Got a repair estimate for my 3 faulty SDM lenses ....: Pentax SLR Talk Forum: Digital Photography Review
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