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AussieTrev · 08-01-2015, 02:53 PM

Do we have a list of serial numbers for the DA* 16-50 that had the SDM failure? My wife's lens has stopped focusing. It is a newer lens than mine and mine is fine. Thanks for any help.

LensBeginner · 08-01-2015, 03:08 PM

Closest I could find, goes for year:
Pentax SDM Failure Survey Results - Articles and Tips | PentaxForums.com

There's been also been a thread about a "resuscitation" method, can't remember exactly, but involved moving the thing by hand while cycling the af selector, and there was speculation about the fact that failures could be related more to something like grease solidifying rather than the motor itself breaking apart.

Edit: aaaah, there it is!

worth a try, at least...
https://www.pentaxforums.com/forums/10-pentax-slr-lens-discussion/300459-foun...-failures.html

**RobA_Oz** · 08-01-2015, 03:35 PM

Originally posted by LensBeginner

Closest I could find, goes for year:
Pentax SDM Failure Survey Results - Articles and Tips | PentaxForums.com

There's been also been a thread about a "resuscitation" method, can't remember exactly, but involved moving the thing by hand while cycling the af selector, and there was speculation about the fact that failures could be related more to something like grease solidifying rather than the motor itself breaking apart.

Edit: aaaah, there it is!

worth a try, at least...
https://www.pentaxforums.com/forums/10-pentax-slr-lens-discussion/300459-foun...-failures.html

I used that method for a long time, until it didn't work any more, so then I had to start taking the lens apart to unstick it. The description of motor "burnout" (I've never seen it described as "breaking apart") I believe is misleading, as it's a piezo-electric drive. Eventually, I gave up and converted it to screw drive, and even though it's noisier in that mode, it isn't terrible and it's reliable, at least.

**jatrax** · 08-01-2015, 04:06 PM

Originally posted by AussieTrev

Do we have a list of serial numbers for the DA* 16-50 that had the SDM failure? My wife's lens has stopped focusing. It is a newer lens than mine and mine is fine. Thanks for any help.

Serial number lists only go so far. The newer ones should be more reliable but that does not mean they are 100%. And I believe it was in 2012 that the statement was made that new ones would not have the issue. So even if newer it has to be made 2012 or later.

I had mine repaired once, the second time I just converted it to screw drive and never looked back. I don't find the noise any different than the squeaks the SDM was giving out and it is now rock solid reliable. And though subjective, I think it focuses faster now.

pathdoc · 08-01-2015, 04:30 PM

It's this sort of thing that hardens my hostility to anything except screw drive or MF. The easiest way to convert to screw drive is of course to fit the lens to an *istD series body.

Adam · 08-01-2015, 06:22 PM

SDM failure has really given Pentax some bad rep in the silent AF department.

Fortunately the newer DC motors are much more reliable.

Sandy Hancock · 08-01-2015, 06:54 PM

For what it's worth, compared to other screw drive lenses a converted DA*16-50 is very quiet. I suspect the polycarbonate and the mass of glass helps to dampen the noise.

**Canada_Rockies** · 08-01-2015, 09:31 PM

I bought both the DA* 50-135/2.8 and the DA* 16-50/2.8 in 2007 when I first got my K10D. Wouldn't you know it was the 50-135 that lost its SDM? The one where I actually used AF? If the 16-50 SDM goes, it won't matter at all. In that focal range, MF is better in my eyes than AF.

AussieTrev · 08-01-2015, 09:52 PM

Originally posted by LensBeginner

aaaah, there it is! worth a try, at least...

Gave it a try and it working again. I think the lens is just over 2 years old so I might be out of luck with warranty, but will give it a try through the local agent. Might get lucky.

Thanks heaps for the feed back.

LensBeginner · 08-02-2015, 12:59 AM

Originally posted by AussieTrev

Gave it a try and it working again. I think the lens is just over 2 years old so I might be out of luck with warranty, but will give it a try through the local agent. Might get lucky.

Thanks heaps for the feed back.

Whatever works...

My pleasure

08-01-2015, 02:53 PM	#1
AussieTrev Veteran Member Join Date: Jul 2010 Location: Queensland Photos: Gallery \| Albums Posts: 3,590	SDM Failure 16-50. Do we have a list of serial numbers for the DA* 16-50 that had the SDM failure? My wife's lens has stopped focusing. It is a newer lens than mine and mine is fine. Thanks for any help.

08-01-2015, 06:22 PM	#6
Adam Administrator Site Webmaster Join Date: Sep 2006 Location: Arizona Photos: Gallery \| Albums Posts: 51,608	SDM failure has really given Pentax some bad rep in the silent AF department. Fortunately the newer DC motors are much more reliable. Adam PentaxForums.com Webmaster (Site Usage Guide \| Site Help \| My Photography) PentaxForums.com server and development costs are user-supported. You can help cover these costs by donating or purchasing one of our Pentax eBooks. Or, buy your photo gear from our affiliates, Adorama, B&H Photo, KEH, or Topaz Labs, and get FREE Marketplace access - click here to see how! Trusted Pentax retailers:

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08-01-2015, 03:08 PM	#2
LensBeginner Veteran Member Join Date: Sep 2014 Photos: Albums Posts: 4,696	Closest I could find, goes for year: Pentax SDM Failure Survey Results - Articles and Tips \| PentaxForums.com There's been also been a thread about a "resuscitation" method, can't remember exactly, but involved moving the thing by hand while cycling the af selector, and there was speculation about the fact that failures could be related more to something like grease solidifying rather than the motor itself breaking apart. Edit: aaaah, there it is! worth a try, at least... https://www.pentaxforums.com/forums/10-pentax-slr-lens-discussion/300459-foun...-failures.html

08-01-2015, 03:35 PM	#3
RobA_Oz Site Supporter Join Date: Nov 2008 Location: Tasmania, Australia Photos: Gallery Posts: 8,209	Originally posted by LensBeginner Closest I could find, goes for year: Pentax SDM Failure Survey Results - Articles and Tips \| PentaxForums.com There's been also been a thread about a "resuscitation" method, can't remember exactly, but involved moving the thing by hand while cycling the af selector, and there was speculation about the fact that failures could be related more to something like grease solidifying rather than the motor itself breaking apart. Edit: aaaah, there it is! worth a try, at least... https://www.pentaxforums.com/forums/10-pentax-slr-lens-discussion/300459-foun...-failures.html I used that method for a long time, until it didn't work any more, so then I had to start taking the lens apart to unstick it. The description of motor "burnout" (I've never seen it described as "breaking apart") I believe is misleading, as it's a piezo-electric drive. Eventually, I gave up and converted it to screw drive, and even though it's noisier in that mode, it isn't terrible and it's reliable, at least.

08-01-2015, 04:06 PM	#4
jatrax Site Supporter Join Date: May 2010 Location: Washington Cascades Photos: Gallery \| Albums Posts: 12,991	Originally posted by AussieTrev Do we have a list of serial numbers for the DA* 16-50 that had the SDM failure? My wife's lens has stopped focusing. It is a newer lens than mine and mine is fine. Thanks for any help. Serial number lists only go so far. The newer ones should be more reliable but that does not mean they are 100%. And I believe it was in 2012 that the statement was made that new ones would not have the issue. So even if newer it has to be made 2012 or later. I had mine repaired once, the second time I just converted it to screw drive and never looked back. I don't find the noise any different than the squeaks the SDM was giving out and it is now rock solid reliable. And though subjective, I think it focuses faster now.

08-01-2015, 04:30 PM	#5
pathdoc Pentaxian Join Date: Mar 2015 Photos: Gallery \| Albums Posts: 6,381	It's this sort of thing that hardens my hostility to anything except screw drive or MF. The easiest way to convert to screw drive is of course to fit the lens to an *istD series body.

08-01-2015, 06:54 PM	#7
Sandy Hancock Moderator Site Supporter Join Date: Feb 2012 Location: Adelaide Hills, South Australia Photos: Gallery \| Albums Posts: 11,275	For what it's worth, compared to other screw drive lenses a converted DA*16-50 is very quiet. I suspect the polycarbonate and the mass of glass helps to dampen the noise.

08-01-2015, 09:31 PM	#8
Canada_Rockies Loyal Site Supporter Join Date: Nov 2007 Location: Sparwood, BC, Canada Photos: Gallery \| Albums Posts: 12,385	I bought both the DA* 50-135/2.8 and the DA* 16-50/2.8 in 2007 when I first got my K10D. Wouldn't you know it was the 50-135 that lost its SDM? The one where I actually used AF? If the 16-50 SDM goes, it won't matter at all. In that focal range, MF is better in my eyes than AF.

08-01-2015, 09:52 PM	#9
AussieTrev Veteran Member Join Date: Jul 2010 Location: Queensland Photos: Gallery \| Albums Posts: 3,590 Original Poster	Originally posted by LensBeginner aaaah, there it is! worth a try, at least... Gave it a try and it working again. I think the lens is just over 2 years old so I might be out of luck with warranty, but will give it a try through the local agent. Might get lucky. Thanks heaps for the feed back.

08-02-2015, 12:59 AM	#10
LensBeginner Veteran Member Join Date: Sep 2014 Photos: Albums Posts: 4,696	Originally posted by AussieTrev Gave it a try and it working again. I think the lens is just over 2 years old so I might be out of luck with warranty, but will give it a try through the local agent. Might get lucky. Thanks heaps for the feed back. Whatever works... My pleasure

SDM Failure 16-50.

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