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07-10-2012, 06:20 PM   #31
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QuoteOriginally posted by Tom S. Quote
Bull crap. You may equate your statement to consumer's electronics devices that change everyday, like cell phones, but comparing a camera lens to consumer electronics is asinine. Do you really believe your camera was only designed to last 2 years or that any of the lenses were? How about the radio in your car, or even your computer for that matter.
The camera might last for much longer but i doubt they are designed with the goal to make it a long lasting product, lenses is something else but the motors in them won't last decades but they are designed to be replaceable items.

hmmm computers change everyday you know....

07-10-2012, 06:37 PM   #32
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QuoteQuote:
Perhaps. It's important to note that Lens Rentals does not rent Pentax equipment.
They do have a survey on the site which asks how many people have recieved defective lenses. They consider lenses that break during use a separate issue, which if you think about it it is. There could be other parties at fault than the manufacture that would cause a lens to stop working, not that anyone here would ever bump a lens and then report it as a failure.

According to the lens play survey, Pentax is top of the heap in initial quality.

QuoteQuote:
Pentax lenses - 1769 with 112 defects
The probability of getting a good lens is 94 %
The probability of getting 5 good Pentax lenses in a row is 72 %
LensPlay - Lens defects

It would be remiss of me to point to point out that this is the first survey I've seen that rated all brands of lenses... it would suggest that a lot of bad mouthing , complainers might owe Pentax an apology. I suggest all off you go read the survey, and adjust your comments accordingly. We've had lot's of people come on and trash Pentax and compare them poorly to other camera companies. So it looks like they were un-informed.
07-10-2012, 06:46 PM   #33
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QuoteOriginally posted by normhead Quote
They do have a survey on the site which asks how many people have recieved defective lenses. They consider lenses that break during use a separate issue, which if you think about it it is. There could be other parties at fault than the manufacture that would cause a lens to stop working, not that anyone here would ever bump a lens and then report it as a failure.

According to the lens play survey, Pentax is top of the heap in initial quality.



LensPlay - Lens defects

It would be remiss of me to point to point out that this is the first survey I've seen that rated all brands of lenses... it would suggest that a lot of bad mouthing , complainers might owe Pentax an apology. I suggest all off you go read the survey, and adjust your comments accordingly. We've had lot's of people come on and trash Pentax and compare them poorly to other camera companies. So it looks like they were un-informed.
Sorry, not convincing because Pentax does have some great lenses - just not the SDMs and this thread is about them and not Pentax overall. They're unreliable based on reports here at PF where folks are a wee bit bias in favor of Pentax.
07-10-2012, 07:11 PM   #34
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gaps in knowledge

QuoteOriginally posted by Docrwm Quote
Sorry, not convincing because Pentax does have some great lenses - just not the SDMs and this thread is about them and not Pentax overall. They're unreliable based on reports here at PF where folks are a wee bit bias in favor of Pentax.
My 2cents is that we have enough of a gap in hard data to prove conclusively that SDM is a dud RE: repair record but the anecdotal and survey evidence is compelling. I have stayed away from SDM so far but keep being tempted. I like what LensRentals said about 1. recent, 2. IS, 3. zooms are "an accident waiting to happen". I also like the further comment that Sigma wide zooms and primes are very reliable - wouldn't think that from the large sample data of the LensPlay report and comparatively high failure rates of the Sigmas (especially now, since Sigma has gone whole-hog for building in OS into every cotton picking zoom they redesign and a complete waste of money and weight for Pentax and Sony users). So, in comparison to others, and in comparison to the whole range of types of lenses on the market, SDM still feels like it is similar to the mechanical vagarities of a problematic design. Some may never fail, others may fail repeatedly. It seems to be a design issue similar to the complexity of what other manufacturers are experiencing (YES, a redesign of the motor is absolutely warranted, even mandated, based on staying competitive in an extreme marketplace). Again, I am drawing a summary of feelings I get when I read these reports, especially from experienced people like LensRentals and LensPlay. I might go for one SDM (50-135) and keep it at that, perhaps budget for an extended warranty plus a repair down the road. Maybe......or go for a Sigma or Tamron which have horrible record of decentering, sticking apertures, build quality, etc problems (or just keep my ca.1980's Tamron 19AH bought used for $85 and put up with the MF hassle). What fun!




Last edited by goldenarrow; 07-10-2012 at 07:19 PM. Reason: text
07-10-2012, 07:58 PM   #35
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The 16-50 and 50-135 where pentax first lenses with a build-in motor like the SDM and they also included a screw mount, i think they wanted too much with those lenses.
I wonder if they can not now simply pull out the screw drive and make the whole AF system less complex, i wonder how much that will help in reliability.
07-10-2012, 08:04 PM   #36
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QuoteQuote:
They're unreliable based on reports here at PF where folks are a wee bit bias in favor of Pentax.
You can't be serious. ( I feel like John McEnroe). I'm guessing the opposite. I'm guessing everyone who has had a problem here on the forum has rushed to fill in the survey while I bet there are a pile of people out there with working SDM lenses who just don't care enough to bother. Your problem with the reports not being related to SDM... which in itself is on error, because some of those lenses are SDM lenses, so SDM does make up part of that result, and because you assume that this forum is more accurate because of a bias that may or may not exist. The accuracy of this forum cannot be assumed without some kind of independent evaluation. The Lensplay survey, while not without it's faults is clear evidence that the SDM shiner on the forum may not be right.. that what Pentax says , that SDM has about the same failure rate as it's other lenses, etc may in fact also be right. There's a difference between evidence, and conclusive evidence.. but suggesting reasons why one set of evidence might not be incorrect does not by default mean another set of evidence is correct. The anti Pentax bias displayed by those who've recieved a bad lens is virulent. And apparently not at all justified in the overall scheme of things, looking at the camera industry as a whole. Personally, I have 6 Pentax lenses, one SDM , all good. I've had 3 Sigma lenses , 2 bad upon delivery. My experience parallels the Lensplay survey, not the Forum survey.
07-11-2012, 03:36 AM   #37
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QuoteOriginally posted by robgo2 Quote
I, too, thought that things were better until my three year old DA*16-50 failed recently. Not surprisingly, I have changed my mind about that. Although the SDM failure survey on this site may not be scientific, the percentage of reported failures of the 16-50 is too high to be a matter of adverse selection.

Rob
Well, I expect to eventually need to replace the motors in all my lenses. I hope they last six or seven years, but who knows? I just know that the chatter about SDM failures has dropped off considerably from three years ago.
07-11-2012, 03:57 AM   #38
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The chatter is there, there is one every month but the reports of SDM not working are getting rare.
Maybe everyone knows the drill by now?

07-11-2012, 04:01 AM   #39
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QuoteOriginally posted by normhead Quote
You can't be serious. ( I feel like John McEnroe). I'm guessing the opposite. I'm guessing everyone who has had a problem here on the forum has rushed to fill in the survey while I bet there are a pile of people out there with working SDM lenses who just don't care enough to bother. Your problem with the reports not being related to SDM... which in itself is on error, because some of those lenses are SDM lenses, so SDM does make up part of that result, and because you assume that this forum is more accurate because of a bias that may or may not exist. The accuracy of this forum cannot be assumed without some kind of independent evaluation. The Lensplay survey, while not without it's faults is clear evidence that the SDM shiner on the forum may not be right.. that what Pentax says , that SDM has about the same failure rate as it's other lenses, etc may in fact also be right. There's a difference between evidence, and conclusive evidence.. but suggesting reasons why one set of evidence might not be incorrect does not by default mean another set of evidence is correct. The anti Pentax bias displayed by those who've recieved a bad lens is virulent. And apparently not at all justified in the overall scheme of things, looking at the camera industry as a whole. Personally, I have 6 Pentax lenses, one SDM , all good. I've had 3 Sigma lenses , 2 bad upon delivery. My experience parallels the Lensplay survey, not the Forum survey.
That's the problem, the survey is not independant.
Information about a store how many they sold and how many return with a problem would be more reliable info, here in the EU at least you need to contact the store first and they handle things with Pentax.
They also have insight in probably other brands as well... we could maybe ask SRS microsystem in London for some info, they are the main store in the UK i believe?
07-11-2012, 04:44 AM   #40
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QuoteOriginally posted by Anvh Quote
uhhh catastrophic failure, like that the lens explode or stop working? we are talking only about AF the rest of the lens is still fine.
Most repairs SDM repairs involve unsrewing the back of the lens where the mount it, it's basically a cover where the electronics are and the SDM.
Not sure how the SDM is held in placed but it's meant to be replaceable so not a big of an deal really.

The report is few hundred pages so there would be data about the kind of failures i assume.

Well that's a warranty problem, something very else you went on about first. And it's not 40% of the value it's 10 to 15% and that's with the man hour, you can actually replace the motor yourself if you want.
Here in my country there is a law about that actually extend the warranty of the product by expected expectations. The DA* range is put forward as a professional lens serries and as such it's expected to be better and more reliable then the consumer product so that the lens stop working after 6 years is unacceptable since there are many cases of SDM failures that makes it a strong case for me. I'm not worried.

Fixed income is much better you know what you get at the moment i don't have that luxury so i need to watchout what i do...
When my SDM went, I couldn't focus the lens on auto or manual. I consider that catastrophic since with the exception of the one focus point it was stuck at, it was useless. I'm not sure where you get the idea that most SDM repairs can be easily fixed. The link for the self repair has people stating it didn't work for them. I can tell you first hand it didn't work for me. So without the parts, how easy to fix is it? Are you suggesting the repair facilities are ripping us off because this is such an easy fix?

I'm glad you have warranty protection in your country, but what about the rest of the world? I'm not even sure what the point of that comment was. Sounds like you have the attitude that since you are covered, you don't care about anyone else.

BTW: Fixed income means I'll have the same rate of income in twenty years that I have now. Ever heard of inflation? When I was working, I seldom cared about inflation because my rate of pay was adjusted for it, plus I could always work more hours if I needed extra income.
07-11-2012, 10:39 AM   #41
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If that's the case then it wasn't your SDM since there is a clutch between the systems or else you would turn the motor while manual focusing.

i'm not talking about the fix in the link, that might work for some but i'm talking about actually replacing the motor. In your case it was the gearing that most likely failed so that wouldnt have helped.

Should i be concerned about the rest of the world? there are so many different rules as there are countries and i ain't going to learn them.
I'm saying that in my case i'm covered and i know the country i live isnt the only one with this system it's quite normal in the EU i believe, we do you want me to do feel sorry about you living in the USA? That''s quite silly right and doesnt solve a thing.

Ah yes in such a way, well sorry that you live in the USA maybe it's time to move?
07-11-2012, 10:56 AM   #42
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QuoteOriginally posted by normhead Quote
You can't be serious. ( I feel like John McEnroe). I'm guessing the opposite. I'm guessing everyone who has had a problem here on the forum has rushed to fill in the survey while I bet there are a pile of people out there with working SDM lenses who just don't care enough to bother. Your problem with the reports not being related to SDM... which in itself is on error, because some of those lenses are SDM lenses, so SDM does make up part of that result, and because you assume that this forum is more accurate because of a bias that may or may not exist. The accuracy of this forum cannot be assumed without some kind of independent evaluation. The Lensplay survey, while not without it's faults is clear evidence that the SDM shiner on the forum may not be right.. that what Pentax says , that SDM has about the same failure rate as it's other lenses, etc may in fact also be right. There's a difference between evidence, and conclusive evidence.. but suggesting reasons why one set of evidence might not be incorrect does not by default mean another set of evidence is correct. The anti Pentax bias displayed by those who've recieved a bad lens is virulent. And apparently not at all justified in the overall scheme of things, looking at the camera industry as a whole. Personally, I have 6 Pentax lenses, one SDM , all good. I've had 3 Sigma lenses , 2 bad upon delivery. My experience parallels the Lensplay survey, not the Forum survey.
If you look at the survey results, you will see that not all of the SDM lenses have high rates of user reported failures. I believe that this refutes your contention that those with failed lenses are skewing the results. The survey is not scientific, but the results are still highly suggestive of an actual defect in the design or manufacture of some of the SDM mechanisms.

Rob
07-11-2012, 10:59 AM   #43
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QuoteOriginally posted by robgo2 Quote
If you look at the survey results, you will see that not all of the SDM lenses have high rates of user reported failures. I believe that this refutes your contention that those with failed lenses are skewing the results. The survey is not scientific, but the results are still highly suggestive of an actual defect in the design or manufacture of some of the SDM mechanisms.

Rob
Rob,
Exactly. I would add that if you look at the Zooms apart from the Primes with SDM the picture is clearer that SDM + Zoom = serious design/manufacture problems.
07-11-2012, 11:09 AM   #44
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QuoteOriginally posted by Anvh Quote
uhhh catastrophic failure, like that the lens explode or stop working? we are talking only about AF the rest of the lens is still fine.
Most repairs SDM repairs involve unsrewing the back of the lens where the mount it, it's basically a cover where the electronics are and the SDM.
Not sure how the SDM is held in placed but it's meant to be replaceable so not a big of an deal really.

The report is few hundred pages so there would be data about the kind of failures i assume.

Well that's a warranty problem, something very else you went on about first. And it's not 40% of the value it's 10 to 15% and that's with the man hour, you can actually replace the motor yourself if you want.
Here in my country there is a law about that actually extend the warranty of the product by expected expectations. The DA* range is put forward as a professional lens serries and as such it's expected to be better and more reliable then the consumer product so that the lens stop working after 6 years is unacceptable since there are many cases of SDM failures that makes it a strong case for me. I'm not worried.

Fixed income is much better you know what you get at the moment i don't have that luxury so i need to watchout what i do...
My DA*16-50 is currently at the C.R.I.S facility for repair, which will cost me about $225 and will carry a warranty of only six months. I have spoken directly with people at Pentax USA who informed me that the repair will be performed with the original--not upgraded--parts. Add to that the reports of repaired SDM lenses failing multiple times, and I am not feeling very good about the 16-50 at the moment. When it works, it is terrific, but when it doesn't, it is an expensive bother.

Rob
07-11-2012, 11:12 AM   #45
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Ur saying they are putting the old type of SDM in the lenses, sounds a bit strange to me.
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