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06-10-2011, 02:20 PM   #16
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QuoteOriginally posted by robgo2 Quote
I have no doubt whatsoever that SDM failure is a bonafide issue with Pentax lenses, but none of its knows is its actual rate of occurrence. Is it 2%, 6%, 10%? I have no idea. But one thing we do know is that people who experience SDM failure are moderately likely to complain about it loudly and repeatedly on forums such as this, which can create an impression that it is more common than it actually is.

My sense is that there were many more failure reports in the first year after the lenses were introduced. If true, this suggests that Pentax has made some adjustments in the fabrication process without any public announcement. It would be very foolish of them not to do so and to continue selling products with a high failure rate. However, if there continues to be an inordinate number of failures in recently produced batches, it would suggest a fundamental design flaw, something that I do not rule out.

I do think that purchasing an extended warranty makes sense, given the cloud of uncertainty that hovers over the SDMs.

Rob
What gets my attention is there are a lot of "regulars" on this site that have had these problems and have been some of the biggest Pentax folks around. Plus, how often to you see a thread "my screw drive autofocus lens failed" much less " my screw drive autofocus lens failed again."

06-10-2011, 03:02 PM   #17
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QuoteOriginally posted by Blue Quote
To be honest, I am surprised that someone hasn't sued the pants off of those Hoya boys over the way they handled this. My experience with Nikon was a lot different. The replaced a sensor in a camera that was 2 years out of warranty because it had been on recall. All I was out of was shipping one way.
I won't be surprised they have kept silence just to avoid any worldwide recall that will cost them a lot. I have no doubt in my mind the SDM was ill designed to begin with. So instead of admitting the problem and going forward, they stick their heads in the sand. I wonder how many potential SDM sales have been lost because of that. Also, they seemed to replace experience engineers with rookies since the take over.
06-10-2011, 11:58 PM   #18
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As much as I don't like how Hoya and Pentax handled the SDM issue I don't think it's SDM as such to be blamed. If you think of it, there are 7 lenses with it out of which 3 are primes. I've heard only one instance of SDM dying on DA*300 and haven't heard anything about troublesome 55 or 200. I've seen one thread saying 17-70 died and one or two with 60-250. The two lenses that keep failing are 16-50 + 50-135. Now correct me if I'm wrong but aren't they the only ones with combination of being zoom and having both SDM and screw drive? This would lead me to believe that it's the implementation of combined AF drive in zooms (60-250 and 17-70 are SDM only and 200+300 have both screw and SDM but are primes) rather than issue with SDM motors themselves. Also huge delay of DA*60-250 speaks out loud if you ask me...

All this aside, my local Pentax dealer (one of the biggest and best in UK) says that SDM issue was blown out of proportion on forums...
06-11-2011, 12:11 AM   #19
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QuoteOriginally posted by axl Quote
As much as I don't like how Hoya and Pentax handled the SDM issue I don't think it's SDM as such to be blamed. If you think of it, there are 7 lenses with it out of which 3 are primes. I've heard only one instance of SDM dying on DA*300 and haven't heard anything about troublesome 55 or 200. I've seen one thread saying 17-70 died and one or two with 60-250. The two lenses that keep failing are 16-50 + 50-135. Now correct me if I'm wrong but aren't they the only ones with combination of being zoom and having both SDM and screw drive? This would lead me to believe that it's the implementation of combined AF drive in zooms (60-250 and 17-70 are SDM only and 200+300 have both screw and SDM but are primes) rather than issue with SDM motors themselves. Also huge delay of DA*60-250 speaks out loud if you ask me...

All this aside, my local Pentax dealer (one of the biggest and best in UK) says that SDM issue was blown out of proportion on forums...
It may have more to do with the fact that those DA* zooms are not only IF but internal zoom as well. The 17-70 is IF but not internal zoom. The 60-250 is a much newer design. As far as Pentax and what few dealers there are around saying it is blown out of proportion, Hoya/Pentax could have mitigated this by having a better warranty on the DA* lenses given their price point, the DA 17-70 could even have a little better warranty but not as good as the DA*.

06-11-2011, 06:38 AM   #20
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QuoteOriginally posted by axl Quote
Now correct me if I'm wrong but aren't they the only ones with combination of being zoom and having both SDM and screw drive? This would lead me to believe that it's the implementation of combined AF drive in zooms (60-250 and 17-70 are SDM only and 200+300 have both screw and SDM but are primes) rather than issue with SDM motors themselves. Also huge delay of DA*60-250 speaks out loud if you ask me...
Actually, the DA*60-250 has both an SDM motor and a screw drive.

It was actually kind of cool when I tried it (and my other DA* lenses) out on an K10D body last week with firmware v1.2. As other have said in the past, it would be great if Pentax updated the firmware on all of their bodies to allow the user to select SDM or the screw drive on lenses that support both.
06-11-2011, 09:25 AM   #21
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QuoteOriginally posted by Blue Quote
What gets my attention is there are a lot of "regulars" on this site that have had these problems and have been some of the biggest Pentax folks around. Plus, how often to you see a thread "my screw drive autofocus lens failed" much less " my screw drive autofocus lens failed again."
I do have a 16-45 where the screw drive gears are off and I need to get it repaired ~$200. That said, I still have not acquired an SDM lens. Actually, I have gone backwards as my last two lens have been pure manual focus, manual aperture - a Super Tak and a Contax Zeiss.

06-11-2011, 09:58 AM   #22
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QuoteOriginally posted by interested_observer Quote
I do have a 16-45 where the screw drive gears are off and I need to get it repaired ~$200.
Lucky you, that is like winning the lottery.

I'm not a fan for the 16-50, but I can recommend 50-135 and 60-250 and for peacesakes take some extra warrenty if you like.
06-11-2011, 10:30 AM   #23
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QuoteOriginally posted by dgaies Quote
Actually, the DA*60-250 has both an SDM motor and a screw drive.
.
Didn't know that! Thanks foe pointing it out

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