[snake]

The 16~50 was once known to have an uncommonly high incidence of SDM failures, which seem to have abated more recently. I don't recall the 50~135 having been prone to an unusual SDM failure rate. Some, sure, but it's old news anyway -- linky linky.

Of course we could be wrong and you could be correct. I'm interested in your citations - can you provide links?

The German and French forums are still reporting failures of later production runs. Not to mention, repairs were made using supposedly improved parts (which people keep dropping, but not a single person has been able to back it up) that are failing repeatedly, as well.

[monochrome]

The German and French forums are still reporting failures of later production runs. Not to mention, repairs were made using supposedly improved parts (which people keep dropping, but not a single person has been able to back it up) that are failing repeatedly, as well.

Cites? I'm not grinding an axe here and I'm not a fanboy. I'm just tired of "received wisdom" and "settled science" that - well - isn't.

[Uluru]

The German and French forums are still reporting failures of later production runs. Not to mention, repairs were made using supposedly improved parts (which people keep dropping, but not a single person has been able to back it up) that are failing repeatedly, as well.

Another Toyota case? Shall we send all later SDM lenses to NASA, to spend one year of unbiased research to ascertain the truth, or we'll unconditionally believe everything posted in an online forum somewhere, and based on .. what exactly? I'm telling you, let Pentax not release something in 6 months, even screwdrive lenses will start exploding before people's noses.

[snake]

Cites? I'm not grinding an axe here and I'm not a fanboy. I'm just tired of "received wisdom" and "settled science" that - well - isn't.

No further than the German and French forums. If you can read German and French, they are there and searchable. Even megathreads. They have fewer apologists on their forums than the English-speaking ones.

[MMVIII]

No further than the German and French forums. If you can read German and French, they are there and searchable. Even megathreads. They have fewer apologists on their forums than the English-speaking ones.

That's a useless reference, just a plain unsubstantiated claim. However, reading f.e. the largest german pentax related forum (dfn) there is one thread where not a single person claims a defect (of the type common to older version) of a new series of the sdm lenses.
Nevertheless, the 16-50 seems to be on the way to be replaced next...

[snake]

there is one thread where not a single person claims a defect (of the type common to older version)

This is a fabrication. Not to mention, multiple posts of repaired lenses failing, too.

As far as "unsubstantiated" goes, nothing is more unsubstantiated than the claims of:

-SDM problems in the past (as we've seen for four years now)
-new parts that will eliminate failures (as we've seen for four years now, yet failures continue and no one will back up the sources for the claims of new parts, nor will part numbers be supplied)
-repaired lenses receive redesigned parts, thus failures would be in the past (tell that to people on their fourth repairs, including on the German forums)

Backing up the issues:

-out of desperation, a FW hack was developed by Pentax users to simply bypass the SDM altogether because who likes being left with an AF lens that doesn't do such things as AF?
-Pentax (now Ricoh) offer rather poor warranties on their lenses. At least the EU mandates a 2 year warranty. Luckily, Pentax doesn't offer that for the US. My Tamron 17-50 has a 5 year warranty.

Luckily, Pentax doesn't sell much in Europe, so little to worry about for them, I guess.

Additional problems with such lenses as the 16-50:

-decentered elements (which many don't like talking about, but there are many of them)

My opinion:

-people don't want their SDM lenses to lose any further value, so they reject/deny/spam any and all threads about SDM failures using distortion of stats, distorted interpretation, relying on anecdotal evidence to reject any claims people made about their own failures, perpetuation of the "redesigned parts" rumor that has NEVER, in four years, been substantiated in any way, shape, or form.

[monochrome]

-people don't want their SDM lenses to lose any further value, so they reject/deny/spam any and all threads about SDM failures using distortion of stats, distorted interpretation, relying on anecdotal evidence to reject any claims people made about their own failures, perpetuation of the "redesigned parts" rumor that has NEVER, in four years, been substantiated in any way, shape, or form.

Wow - that would be quite a conspiracy. Just as likely the FR. and Gr. Forum threads are populated by posters who don't even own the lenses but make unsubstantiated posts to keep the pot stirred because they don't want to let their evenings' entertainment end.

[snake]

Wow - that would be quite a conspiracy. Just as likely the FR. and Gr. Forum threads are populated by posters who don't even own the lenses but make unsubstantiated posts to keep the pot stirred because they don't want to let their evenings' entertainment end.

Can you provide proof of "redesigned SDM parts", in the form of direct visual comparisons, part numbers, vendor information, etc.?

I know I've tried to get this information direct from Pentax and they won't give it up. Others have tried with the Pentax DE/AT/CH distributor, but they are dead in the water anyhow, ignoring parts request emails while simultaneously playing on Facebook all day.

[monochrome]

Can you provide proof of "redesigned SDM parts", in the form of direct visual comparisons, part numbers, vendor information, etc.?

I know I've tried to get this information direct from Pentax and they won't give it up. Others have tried with the Pentax DE/AT/CH distributor, but they are dead in the water anyhow, ignoring parts request emails while simultaneously playing on Facebook all day.

Nope. We've argued this to a standstill on this Forum. All we have is what I originally wrote. posters suspect Pentax quietly changed SDM; lenses made in more recent batch runs seem to have fewer failures; there's a Serial Number thread to attempt to identify batch runs; Pentax is silent; believe what you want.

The frequency of failed SDM post has decreased dramatically. No one can prove anything.

[snake]

Nope. We've argued this to a standstill on this Forum. All we have is what I originally wrote. posters suspect Pentax quietly changed SDM; lenses made in more recent batch runs seem to have fewer failures; there's a Serial Number thread to attempt to identify batch runs; Pentax is silent; believe what you want.

The frequency of failed SDM post has decreased dramatically. No one can prove anything.

So that rumor started here?

Most of the variants I've read throughout the forums has been that Pentax has said it directly and said it to customers.

As far as "fewer failures" goes, it's too early to tell, especially if the sales of SDM lenses are lower than earlier. Going by that Pentax engineer interview posted on this very forum, SDM's problems, according to him, weren't solved until mere months ago, but the fundamental design problems remain.

And again, the decentered elements in the 16-50 were/are also an issue.

How the Tokina-branded variants fare with other manufacturers is beyond me.

[gazonk]

So that rumor started here?

Yes and no (it started as an statement from an employee, not a rumor): Jens Petersen of Pentax Germany said it to Pentaxforums in an interview: Pentax Engineer on SDM Failure and Pentax DC - Photokina 2012 - PentaxForums.com

I did a search on a couple of German forums and can't say the tone is much different from here.

And for the record: I have no SDM lenses and have no intention to by any SDM lens, I'm fine with screw drive lenses until they come up with something more trustworthy.

[mecrox]

Nope. We've argued this to a standstill on this Forum. All we have is what I originally wrote. posters suspect Pentax quietly changed SDM; lenses made in more recent batch runs seem to have fewer failures; there's a Serial Number thread to attempt to identify batch runs; Pentax is silent; believe what you want.

The frequency of failed SDM post has decreased dramatically. No one can prove anything.

I don't think anything needs to be proved because in this biz perception is all. The perception among a lot of folks is that SDM is or was inherently faulty, that SDM lenses are not to be trusted, and that Pentax knew all about it but stonewalled instead of tackling the problem upfront.

All this really says to me is that a lot of Japanese companies are culturally incapable of establishing a rapport or relationship with their end-users and won't stand behind their products other than with the legal minimum guarantees. Its unfair to single out Pentax, of course: most of them are at it in one way or another. A company more sensitive to its customers and what they think would have quietly scuttled SDM and all who sail in her a very long time ago. It was pretty clearly damaging the brand regardless of whether or not the brouahaha was justified. Fact of business life really.

Even so, my guess would be that in the end this incapacity to relate is going to cost Japan Inc. a fortune and drive some companies to the wall. The reason is that Westernized IT companies, who understand consumer relations only too well, are running rings round Japan Inc.'s stuttering attempts at innovation and customer relationships. The camera companies have already lost the P&S biz: so, what next?

Just my 2 cents, of course. Even so, my own SDM experience - a 16-50mm which had to be sent back twice in two months at considerable expense after I bought it new in 2012 - has changed my view of Pentax. The SDM products are all very expensive, higher-end items. People are quite right to expect the product to live up to that and for the company to stand behind what they make whether one unit fails or 1000 fail. That simply has not happened.

[H. Sapiens]

I don't know if recent lenses have problems or not. But I just searched for "Pentax SDM" and the second link, following wikipedia's article, is a post from this forum aiming to document just how common the problem is (or was) and the 6th post deals with DIY-fixing a lens with said problems. Even if recent lenses don't fail, Ricoh have a very real problem in public perception of the reliability of the lenses. It makes me wonder if the dollars Pentax have saved in the repair department by not communicating openly about perceived issues and how they dealt with it, have not more than eating up by less activity in the sales department. It is also interesting that no lenses with SDM have been introduced for a couple of years now. Will we see more updated lenses, like the DAs?

Edit: Mecrox managed to write his long, elaborate post while I wrote mine, which now have the bad fortune of looking like a poor summary ;-)

[mecrox]

I don't know if recent lenses have problems or not. But I just searched for "Pentax SDM" and the second link, following wikipedia's article, is a post from this forum aiming to document just how common the problem is (or was) and the 6th post deals with DIY-fixing a lens with said problems. Even if recent lenses don't fail, Ricoh have a very real problem in public perception of the reliability of the lenses. It makes me wonder if the dollars Pentax have saved in the repair department by not communicating openly about perceived issues and how they dealt with it, have not more than eating up by less activity in the sales department. It is also interesting that no lenses with SDM have been introduced for a couple of years now. Will we see more updated lenses, like the DAs?

Edit: Mecrox managed to write his long, elaborate post while I wrote mine, which now have the bad fortune of looking like a poor summary ;-)

Aw Next time it will be the other way round, I'm sure

[Barry Pearson]

It is also interesting that no lenses with SDM have been introduced for a couple of years now.

Wasn't the PENTAX DA 18-270mm F3.5-5.6 ED SDM launched just a year ago?

(Just for the record, I bought 2 SDM lenses over 4 years ago, and 2 more about a year and a half ago, they are among my most used lenses, and none of them has had an SDM motor failure).