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02-22-2016, 07:16 PM   #1
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SDM issues today.

Hi all,
I don't currently have any SDM lens and have considered them but honestly reading back on all the past horror stories ,failures, and posts about converting them to screw drive, I have avoided them.

The problem I have with trying to figure out the extent of the problems and if there is still a problem with the SDMs is the info is just really scattered.

Would it be possible for a discussion of the SDM issues today? Was the issue ever resolved by pentax,acknowledged as such? Do new lens with SDM drives have a high failure rate? I know some can be converted to screw drives but thats not something I think you should have to worry about on an expensive new lens....at least I don't want to!

So I guess my question in a round about way of asking is whats the deal with SDM Lenses as they.stand today.

Thanks in advance,
Al

02-22-2016, 07:32 PM   #2
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same with me, i'd like a 50-135, but I guess i'm waiting until its re-released with HD, DC/Ring Drive... maybe it will never be re-released, especially with the new FF focus.

The bigger problem is just that I don't have the money

To answer your question partially, the SDM has been improved, but never acknowledged. There is a very low failure rate, if there is one at all. Its mainly that SDM is not trusted anymore... and that its slowish.
02-22-2016, 07:41 PM   #3
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No problems with my 16-50 and 50-135 since they were fixed 9 months ago with the modified motors...I'm still touching wood...!

https://www.pentaxforums.com/forums/10-pentax-slr-lens-discussion/312649-pent...ml#post3506549
02-22-2016, 07:43 PM - 1 Like   #4
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Years ago, we found out from a Pentax repair guy in Germany that the problem had been resolved. It was never a problem with every lens, but those who suffered a problem were understandably quite vocal. But they carried on for quite a long time after the issue was resolved. That being said, every internal electric motor is going to fail at some point. It was never established that SDM was better or worse than lenses issued by other manufacturers, or that there weren't others with similar problems. At the time SDM was an issue, I read many reports from other brands were people had left one brand for another over similar issues.

The issue largely affects the DA*16-50 as far as we can tell. It seems to have been largely a problem of the lens being slightly underpowered and thus prone to burning out or jamming. The problem seems to have been resolved with the possible introduction of a slightly stronger motor, in later SDM cameras. There are very few problems with the DA*60-250 or DA* 300, and the DA*50-135 while perhaps not as good as those two, never seemed to have had the problem to the same extent as the DA*16-50. The DA* 16-50 has been much better since late 2012 and repairs after that time have had a much higher success rate.

I don't believe Pentax ever acknowledged the issue, my suspicion is that was because the vast majority of lenses actually worked correctly. Again just a suspicion, but I believe that some of the tolerances were not quite specific enough, leading to some lenses having more resistance than others and burning out their motors faster, in some lenses. However when the specs lined up as intended many of the lenses were trouble free.

No one actually knows what was done to increase reliability, but something was done, and the lenses are much more reliable now, but not as reliable as the ring motor lenses, DA 18-135, DA 16-85, D FA 70-200 and D FA 150-450. Although, I've only heard of a very few problems with anything other than the 16-50 and lately the 16-50 is much improved.

So, there is no easy answer to your question... I simply don't think you can make an SDM lens, which is like an internal screw drive as reliable as a ring type motor. But, I'm quite happy with my DA*60-250. As a rough estimate, I'd guess I've taken at least 15,000 images with it over 3 years, and it seems to be completely reliable. Not the fastest, but steady. No one can guarantee you won't have a problem with any lens and if I could just stick to ring motors I would, but the 60-250 is one of my favourite lenses, and it's SDM, and I'd rather not miss out.

I don't think anyone would recommend against buying a DA*60-250, DA*300 or a DA* 200, based on SDM reliability, with the DA*50-135 close behind but not as reliable. Any DA*16-50 would be slightly less reliable than a 50-135 and any 16-50 made before 2012 should probably be looked at with some suspicion if it hasn't had it's motor replaced.

Of course I have no numbers to support any of this, these are just my impressions from following what's going on on the forum.


Last edited by normhead; 02-22-2016 at 07:50 PM.
02-22-2016, 07:48 PM   #5
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The best preventative measure to avoid sdm failure is keep the lens on a body with a charged battery in the body. This will keep the capasitor in the lens from losing charge. The capasitor in the motor is issue. I have a body that my 50-135 never is removed from. If you only have one body then remove the lens and shoot. Always put your sdm lens back on before storing.
02-22-2016, 08:21 PM   #6
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QuoteOriginally posted by macman24054 Quote
The best preventative measure to avoid sdm failure is keep the lens on a body with a charged battery in the body. This will keep the capasitor in the lens from losing charge. The capasitor in the motor is issue. I have a body that my 50-135 never is removed from. If you only have one body then remove the lens and shoot. Always put your sdm lens back on before storing.

I think that's not the issue in most of the past failures. There were some reported where it all came to life after letting charge flow, but most were where the motor seized and had to be replaced.


Master Pentax repairman Erik Henderson notes in an interview on this forum that none of the motors he puts in these days as replacements have ever failed. Make of that what you will.
02-22-2016, 08:59 PM   #7
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QuoteOriginally posted by clackers Quote
...Master Pentax repairman Erik Henderson...
Not to be pedantic, but it's Eric Hendrickson. Enough of a difference that a resultant search might not be successful. Anyway, Eric's website.
02-22-2016, 09:14 PM   #8
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QuoteOriginally posted by macman24054 Quote
The best preventative measure to avoid sdm failure is keep the lens on a body with a charged battery in the body. This will keep the capasitor in the lens from losing charge. The capasitor in the motor is issue. I have a body that my 50-135 never is removed from. If you only have one body then remove the lens and shoot. Always put your sdm lens back on before storing.
I have a pair of SDM lenses, 16-50 and 50-135, they are both earlier versions, both have been replaced with the new parts. My experience with these SDM lenses is that if you are not using them, it is better to be store and kept in the upward position with the front-element down; and I always keep them in the pouch. I have not experienced any sluggishness every time I mount the lens on the camera. Again, I have no scientific proof why the motor is less likely to be stuck when I kept in upside down position when not used. In fact that is when I experienced the SDM problem initially when I left the lens in the camera.

02-22-2016, 09:23 PM   #9
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QuoteOriginally posted by macman24054 Quote
The best preventative measure to avoid sdm failure is keep the lens on a body with a charged battery in the body. This will keep the capasitor in the lens from losing charge. The capasitor in the motor is issue. I have a body that my 50-135 never is removed from. If you only have one body then remove the lens and shoot. Always put your sdm lens back on before storing.
I am just repeating what I have read and the experience of my father and myself. We both have early models and have practiced this for over 3 years with no sluggish performace.
02-22-2016, 09:30 PM   #10
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QuoteOriginally posted by filoxophy Quote
Not to be pedantic, but it's Eric Hendrickson. Enough of a difference that a resultant search might not be successful. Anyway, Eric's website.

Thanks for the save, Filoxophy!
02-23-2016, 02:38 AM - 1 Like   #11
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Hi Al. I found this on the forum and hope it helps you out. I found it an interesting read. I have a DA* 16-50 that hasn't missed a beat. The percentage of failures these days seem pretty few and far between. Good luck.


Pentax SDM Failure Survey Results - Articles and Tips | PentaxForums.com
02-23-2016, 04:27 AM - 1 Like   #12
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QuoteOriginally posted by pjv Quote
Hi Al. I found this on the forum and hope it helps you out. I found it an interesting read. I have a DA* 16-50 that hasn't missed a beat. The percentage of failures these days seem pretty few and far between. Good luck.


Pentax SDM Failure Survey Results - Articles and Tips | PentaxForums.com
Thanks for that survey! Looking at the data it sure looks like there was a major issue with several zooms at least at the point the survey was done to when it closed out.


Norm, thanks for the historical summary! Very helpful.

Thank you everyone else that has commented so far. The impression I am getting is that yes it was a problem, but though they did not acknowledge it as such...it appears that Pentax/Ricoh has taken steps to correct it or minimize in current motors?

With all the discussions on Sdm to screw conversions on the forum and even in the market place one might think the problem was still an issue though , at least its an impression given. Unless people are doing these conversions not because of motor issues but because the sdm is slower than the screw? Id be interested in hearing from people that opted to convert their lens and why.

Thanks,Al
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