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11-23-2009, 12:20 PM   #1
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More SDM problems

My problems with SDM lenses have been pretty well documented here. I just had more experience I thought I would add to the pool in hopes of helping others with similar issues:

Several months ago, my DA* 50-135 had the typical symptoms of SDM failure: (intermittent operation, slow to "wake up" etc. etc.). I sent the lens back to Pentax, for repair, and they sent me a brand new one that worked fine. I used it for a while, and then put it back in storage for a couple of months. Yesterday, I took it out again since I needed to take pictures at my daughter's play, and I needed the wide aperture, and the zoom. Well to my horror, I push the shutter button on the K-7 and...NOTHING. Again, and again...nothing. Took the lens off and on, etc. nothing. then I manually swung the focus back and forth several times, and then pushed the shutter button, and I got a little motion. After going through several cycles of this, the SDM finally "woke up" and started working again.

So it seems that not using the SDM frequently, is just as bad or worse than using it a lot.

Before I get the inevitable "did you clean the contacts" question...the answer is "yes." I cleaned the contacts with microfiber cloth, and they are so clean and shiny you can see yourself in them. It is not the contacts! Also, I take immaculate care of my lenses, storing them in their protective pouches in an air conditioned environment when not being used.

Oh, and it is not the camera either, since the problem happens on both my k20d and K-7.

I am so frustrated with SDM lenses. Five bad copies now (3x DA* 16-50, and 2xDA* 50-135) ALL my other Pentax glass (non SDM) has been flawless since the 1980's.

11-23-2009, 12:41 PM   #2
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I've read about the same thing happening a few times before, so you aren't alone.

Before anyone slams the design I'll point out that it isn't just with SDM lenses.
As an example, if you don't start and move a car from time to time the gas will go stagnent, the rubber will start to rot and you'll have have a host of additional problems after a while.
The best way to avoid problems with anything like a car or even an autofocus lens is use it from time to time. It only takes a few minutes of your time once or twice a month.
11-23-2009, 12:56 PM   #3
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Reading stories like this I'm not feeling bad for selling my DA*50-135. At least my wife has nice set of earrings now and I didn't have to dip into the savings

....and I can buy more primes

Peter
11-23-2009, 01:02 PM   #4
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Aint you the guy sending Pentax gear to the freezing cold, empty and lonely space?

I am sure the Pentax Gods are not happy with this and is somehow getting back at you!




Jokes aside, it is a very scary situation... does anyone know if the newest SDM lenses (DA* 55 & DA 17-70 & DA* 60-250) face the same problem?

11-23-2009, 01:04 PM   #5
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PentaxPoke;

I experienced the EXACT same symptoms as you on my 50-135: it would take about 30-40 seconds to wake-up then it would work OK until I put it away and then it would act the same THE NEXT DAY! I have a K10, 2-K20's and now a K7 and it would exhibit the same problem on all bodies. Cleaned the contacts, played with the focus and zoom rings to no avail. It was like there was a timer in the damn thing!
Went to Pentax Canada here in Mississauga (I work on the next corner), they would of course deny any knowledge of any problems with SDM's, on any lenses! It was quite funny (not really, in retrospect) while I was there arguing with the Pentax rep., when the representative of a reputable distributor here in Toronto walked-in with not one, but two (!) 50-135's with failed SDM's!!!!
They finally took the lens back and gave me another one, one week later, which works OK so far, although the serial number is older that the one I "surrendered". I assume it's a refurb.

To Little Laker's comment: I respectfully disagree. I use this lens or a very regular basis, at least twice a week, and this should NOT be happening. We are not talking about storing the lense for six months to a year here.

Gene
11-23-2009, 01:04 PM   #6
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This is a sad series of events mate.
I really do hope Pentax gets their act together with their SDM lenses - it's becoming more and more of an indicment on their top quality and most expensive lenses.

I'd even gone to the extent of writing a formal letter to Pentax through Adam to voice my concerns and solicit a response on the matter. Nothing yet after over 2 months. Perhaps if others petitioned it may have some effect, but it'd be bad for Pentax to have people walk away from the brand just for their SDM failings.


QuoteOriginally posted by axl Quote
Reading stories like this I'm not feeling bad for selling my DA*50-135. At least my wife has nice set of earrings now and I didn't have to dip into the savings

....and I can buy more primes

Peter
You tease, Peter!
11-23-2009, 01:08 PM   #7
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Have we established what part of the SDM system is causing the failures?
11-23-2009, 01:13 PM   #8
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Judging by the buzzing/whirring noise it was making when trying to focus, I would say it is the micro-motor itself, but I can't prove it. Pentax Canada never gave me any feedback, although I did talk to the Service Manager (Stephen Ho) on the matter.

Gene

11-23-2009, 01:16 PM   #9
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QuoteOriginally posted by Ash Quote
You tease, Peter!
well, 50-135 covers lots of good primes, since I already had F50 (faster, smaller, focuses faster an closer) and Sigma 105 I figured out that by getting another 1 or 2 primes I'll cover the lost range with lenses that are optically as good or better and won't have to run risk of SDM failure.

Jokes aside, it's very sad situation with these lenses...
Good lucck to all owners
11-23-2009, 01:16 PM   #10
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QuoteOriginally posted by PentaxPoke Quote
...

I am so frustrated with SDM lenses. Five bad copies now (3x DA* 16-50, and 2xDA* 50-135) ALL my other Pentax glass (non SDM) has been flawless since the 1980's.
Wow, can't blame you, I'd be too if that happened to me. I'm a big DA Ltd fan, so there's little SDM in my inventory and I only have one SDM Lense, the DA*300, which has showns some intermitent failure but never failed totally on me. I wish it would if it is going to die anytime soon as I only have a few more months of warranty left and sending a perfectly working lens now to Pentax is a waste of time and money. I have to admit that I am no big fan of AF altogether, especially if it's going to be in the lens, any lens, any brand. With stablization in lenses in addition to SDM (non Pentax that is), it's just more things that can go wrong, so switching system is no guaranty of reliability or longevity for that matter. I can't affort most quality modern MF lenses (eg Zeiss), and accurate visual MF is difficult at best on APS-C size viewfinders (not to mention innacurate in the case of my K10D, I can't speak for the K7), so fixing failing AF SDM lenses is I guess still the cheaper alternative in the long run, albeit frustrating I'll admit.
11-23-2009, 02:09 PM   #11
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Oh, well...

I have a failed 50-135mm f/2.8 with SDM.
Two of the four SDM-repair-capable services refused to answer my mails requesting a paid repair. The third replied after a friend living in their country contacted them by phone. Then, I was able to send the lens for repair.
It is now about a month since they have my to-be-repaired lens.
No information is provided on when they will finish fixing the issue.
When I will get my lens back, more than half the price of that lens will be spent to make it work again. And, this is only because Pentax refuses to let me use the "properly functioning" screw-driven AF system. I find this behaviour (with an explained basis) unacceptable.
Here are my questions:
- Why do they charge me for a failed SDM even though I did nothing to make it inoperable? (Has anyone seen warnings on SDM boxes regarding the use of them, specifically? Are we told that these must be treated differently then our other AF lenses? Should we kiss them, for example, before and after each use?)
- Why do they charge me for using AF again even while I have a perfectly solid, fully functional mechanism residing within the lens? Why can't I use it? Didn't I pay for it?

In any case, I doubt if my confidence in this most expensive lens of mine will ever be restored. (Remembering the horror stories that it fails "again").

I certainly do not believe that the problem is the result of my misuse.

I would be willing to "change ship" if I did not currently have three separate Pentax systems including a 35mm and a MF camera, lenses, adapters, strobes, cables as well as the digital stuff...

It is certain, however, that I will never buy another lens with SDM. Period.

(I must stress that, I accept all electronic and mechanical devices may need repairs in their lifetime for whatever reason. What I do not accept is the ignorance).
11-23-2009, 02:14 PM   #12
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When used on a pre-K10D camera it works as a screw-drive, correct?

Does covering up the SDM contacts on the lens revert it to a screw-drive system? How does it know to use SDM vs. screw drive?
11-23-2009, 02:25 PM   #13
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Unfortunately covering the contacts in any combination will not let you use Sd over SDM. It completely sucks and there should be a firmware fix to allow the user to choose the AF drive when they need to. For any user this is wrong but for those that need their cameras and lenses for work, it's even worse.

Imagine you've been paid $3000.00 to shoot an event or wedding and your primary lenses fail mid way through. If you didn't buy backup lenses, you are in serious trouble and there is no reason Pentax should leave you in this situation.

Last edited by Peter Zack; 11-23-2009 at 02:49 PM.
11-23-2009, 02:33 PM   #14
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If you've invested $3,000 in lenses you should be able to trust that the SDM motors don't jam up.

I wonder how many people have had the screwdrive motor fail. Those drive several different lenses without breaking a sweat. For the SDM motor to fail just driving one lens is unacceptable.
11-23-2009, 02:48 PM   #15
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QuoteOriginally posted by sebberry Quote

I wonder how many people have had the screwdrive motor fail.
Uh I would say none! And even if it did, who cares. The lens is the important part and you would just go repair or replace the body if the internal motor failed.

Plus anyone who uses a camera for work will have a couple of extra bodies. So that's an easy swap out in the middle of a shoot.

It's a lot cheaper to have a spare body than to have spares of every important lens you need on hand just in case of a failure.
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