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01-25-2011, 06:41 PM   #166
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QuoteOriginally posted by dankoBanana Quote
all this "SDM failure" wouldn't be such an issue if they offered a 3 year guarantee for their DA* lenses
make it 5 years + excellent repair service.

01-25-2011, 06:43 PM   #167
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QuoteOriginally posted by Pentaxor Quote
make it 5.
Ditto! While 3 would help, 5 would "close the deal".
01-25-2011, 06:45 PM   #168
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QuoteOriginally posted by sewebster Quote
I think for a lot of people the primary concern is really more the annoyance than the money. At least it would be for me, if I owned any SDM lenses. I guess this makes me one of those ridiculous people who posts about problems when they don't even have the product in question


I would certainly be quite annoyed if one of my SDM lenses failed. I was basically just making an argument for why buying used SDM lenses isn't a terrible idea (vs buying a new one if the cost savings is enough) and in the long run can be cost effective. The annoyance factor of having to send your lens into get repaired and not having it in the meantime would be there whether your lens was purchased new and covered under warranty or not.
01-25-2011, 06:48 PM   #169
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I'm just wondering how many people actually bought a non-working SDM lens and for how much. on the otherhand, how many considered selling their non-working SDM lens.

01-25-2011, 07:14 PM   #170
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QuoteOriginally posted by Pentaxor Quote
I'm just wondering how many people actually bought a non-working SDM lens and for how much. on the otherhand, how many considered selling their non-working SDM lens.
Do you mean knowingly or unknowingly?

If we're talking about knowingly (with full disclosure) then I actually sold a DA17-70 a while back that was having some focusing issues. The SDM hadn't failed (yet) but there were issues focusing above 50mm. The price I paid for the lens initially reflected the potential issues. The person who then bought the lens from me was also fully aware of the situation and if I recall correctly I sold the lens for about $200. The buyer did, in the end, replace the SDM motor for a little under $140, so at the end of the day he still got a decent deal by getting a 17-70 (that was in like-new condition) for about $340 total.

If you meant unknowingly, then I suspect it happens occasionally, although probably not much here as most people buying and selling here are pretty well aware of the SDM issue as a whole.
01-25-2011, 07:24 PM   #171
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hello all.
short intro; extreme newbie, with a lot of theoretical background from reading this forum but minimal practical knowledge on sdm lens. i for one, is very keen to get hold of a DA* sdm lens as an upgrade for my kr.
as an observation, there's a lot of positives & negatives posted on this thread.
there's one thing not emphasis is the rate of warranty returns. being in the eng/ manufacturing field, all complaints/ warranty returns are calculated as a % ( as one member highlighted earlier re. statistic)
to put things in general, rate of warranty returns or customer returns ( industry standard) is calculated based on part per million or simply known as ppm. having said that, current standard requirement/ target is 3.4 ppm. or 3.4 rejects per million deemed as industry acceptable standard. mathematical calculation of +/- 6 sigma, within the statistical process control or spc.
however, what we do see in general population, a rate of 2700ppm (spc term known as +/-3sigma) or 2.7 returns per 1000 lens sold is evident. please note this is purely an estimation within my observation on this thread.
as you can see, if you put it in numbers, it's quite big & it can be scary.
so what do we do about it? .
i'm sure pentax knows about this.
was their sdm development & testing completed before they market their product, in order to compete on market share by other competitors? this are the things we won't find out.
on the other hand you have the aftermarket brands or so call 2nd party manufacturers ie sigma, tamron. they reverse engineer a pentax product previously release & sell it a better price & giving longer warranty. this must say something about the quality of their product. perhaps, perhaps not.
so what can we do to help people like ( the unexperience on lens) get a better idea on what to get or not to get?
my suggestion: pentax forum/ review experts should collate all happy & unhappy customers, tabulate these data using a statistical software & put it out for all to look at. this would be great as a quick look up tool. ( it's a big job for one person, but if an automated database is setup within pentax forum, all members need to do is input on items purchased/ return etc. pretty similar to a fill in an online survey)
i could spent a day reading the reviews, which i have, & still ended up with mixed decision as to what's wrong or right.
again, i will elaborate, this is only my own opinion. it's only to be taken up for general reading only.
01-25-2011, 08:08 PM   #172
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From my experience with 2 SDM lenses, I definitely say "wait until a later time to buy SDM". I won't buy another SDM lens for now. Pentax is just too new in this technology. I'll wait them to sort out the problems. AF lens can't auto focus or can't lock focus - this is just too much hassle for me. I regretted that I have bought into them.
01-25-2011, 08:54 PM   #173
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QuoteOriginally posted by dgaies Quote
Do you mean knowingly or unknowingly?

If we're talking about knowingly (with full disclosure) then I actually sold a DA17-70 a while back that was having some focusing issues. The SDM hadn't failed (yet) but there were issues focusing above 50mm. The price I paid for the lens initially reflected the potential issues. The person who then bought the lens from me was also fully aware of the situation and if I recall correctly I sold the lens for about $200. The buyer did, in the end, replace the SDM motor for a little under $140, so at the end of the day he still got a decent deal by getting a 17-70 (that was in like-new condition) for about $340 total.

If you meant unknowingly, then I suspect it happens occasionally, although probably not much here as most people buying and selling here are pretty well aware of the SDM issue as a whole.
knowingly. because for certain, I don't think that anyone would even shell out $650 for a lens that has it's SDM no longer functioning. personally, a non-working AF lens is no better than a manual focus lens and their existing price.

01-25-2011, 09:20 PM   #174
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QuoteOriginally posted by Pentaxor Quote
knowingly. because for certain, I don't think that anyone would even shell out $650 for a lens that has it's SDM no longer functioning. personally, a non-working AF lens is no better than a manual focus lens and their existing price.
That's what I figured you meant. I also recalling seeing a handful of 16-50 and 50-135 lenses with broken SDM motors sell in the 400 dollar range on here over the past year.
01-25-2011, 09:29 PM   #175
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A perfectly working 16-50 with no history of SDM issues sold for $425 (when combined with a K-7)....wish I had jumped on that but had just bought a K-7 body
01-25-2011, 10:07 PM   #176
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QuoteOriginally posted by dgaies Quote
Or most people realize the chance of SDM failure during the first year is actually (far) less than 50%. Given that, a $100 spread on a $200 potential repair isn't really a terrible option, statistically speaking.
Love it! Pentax should start marketing SDM lenses to obsessive gamblers. "Will you have a winner? The only way to know is to PLAY THE GAME!"
01-25-2011, 10:17 PM   #177
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QuoteOriginally posted by Hound Tooth Quote
Love it! Pentax should start marketing SDM lenses to obsessive gamblers. "Will you have a winner? The only way to know is to PLAY THE GAME!"
Once again, you've missed my point entirely and taken what I said out of context. I was addressing the cost/benefits of buying a new vs used SDM lens in response to someone else's question about the spread between new and used prices. If you don't want to take the risk, don't buy an SDM lens. Pretty simple isn't it?
01-25-2011, 11:59 PM   #178
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Well I, for one, hope someone will buy my DA* 50-135mm so I can finally be rid of it once and for all. And based on what I've learned in this thread, I can offer it to obsessive gamblers or clueless individuals who don't know any better. All the apologists already have one, and they've never suffered a failure (of any kind, at any time in their lives, because they are perfect).

I'll be sure and point out that it has a 6 month warranty on the SDM, since that part was replaced TWICE within a month. And I'll let potential saps know that it only costs $280 to get it fixed if it breaks, so the $100 they save now can go towards that eventual repair.

Wow, that's looking like quite the deal!
01-26-2011, 04:45 AM   #179
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QuoteOriginally posted by Hound Tooth Quote
Well I, for one, hope someone will buy my DA* 50-135mm so I can finally be rid of it once and for all. And based on what I've learned in this thread, I can offer it to obsessive gamblers or clueless individuals who don't know any better. All the apologists already have one, and they've never suffered a failure (of any kind, at any time in their lives, because they are perfect).

I'll be sure and point out that it has a 6 month warranty on the SDM, since that part was replaced TWICE within a month. And I'll let potential saps know that it only costs $280 to get it fixed if it breaks, so the $100 they save now can go towards that eventual repair.

Wow, that's looking like quite the deal!
Good luck with your sale.
01-26-2011, 11:08 AM   #180
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QuoteOriginally posted by Chwisch87 Quote
If there really was an issue, the used value of these lenses would go down...
QuoteOriginally posted by Hound Tooth Quote
...Wow, that's looking like quite the deal!
I think the DA* lenses have much more merit than that. I don't think too many people buy the lens because it has SDM focusing, they buy them for the optical quality and WR. You can't really argue against that. While I now avoid SDM lenses due to the reliability problems, I can't ignore their other qualities. They sell for a high price just like an A 50 1.2 does. The 50 is manual focus, but renders beautifully. The SDM lens will be a manual-focus lens sooner or later, but still delivers nice pictures. That's why they hold their value.

QuoteOriginally posted by sewebster Quote
I think for a lot of people the primary concern is really more the annoyance than the money...
This is why I won't buy any more SDM lenses. That and the other reason being if I'm buying an AF lens I want it to AF.
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