[Leaf Fan]

Well, curious thing happened.

I had an SDM failure in late September. I was pretty bummed because I really like the 50-135, it quickly became my favourite lens.

I was going away for most of October, so I had a decision to make, either take the lens into Pentax and not have it for my trips or take it and use it MF only. I decided to take it with me.

Well, lo and behold, I pulled it out of the bag and mounted it, and it worked. Worked flawlessly the entire trip and is still going strong.

I'm tending to think that my initial failure was some type of incorrect mounting on my part, some dust on one of the contacts, or some other "fixable" issue that I didn't notice at the time.

So I'm a happy camper again.

[EsBee]

Well, curious thing happened...

I had an SDM failure...

Well, lo and behold, I pulled it out of the bag and mounted it, and it worked....

Same thing happened with my 16-50mm, which I purchased used not too long ago. I didn't even realize that the SDM was not working and kept shooting away because I was not used to the quiet motor.

After I looked at the photos and realized none of them were in focus, I unmounted the lens, dusted off the contacts on the K20D and the lens, remounted and everything worked fine.

This has happened twice so far. The second time I paid attention and quickly switched to MF and there were no lost shots. Again an unmount, quick dust off and remount fixed it.

[Canada_Rockies]

Well, curious thing happened.

I had an SDM failure in late September. I was pretty bummed because I really like the 50-135, it quickly became my favourite lens.

I was going away for most of October, so I had a decision to make, either take the lens into Pentax and not have it for my trips or take it and use it MF only. I decided to take it with me.

Well, lo and behold, I pulled it out of the bag and mounted it, and it worked. Worked flawlessly the entire trip and is still going strong.

I'm tending to think that my initial failure was some type of incorrect mounting on my part, some dust on one of the contacts, or some other "fixable" issue that I didn't notice at the time.

So I'm a happy camper again.

I sent mine off with the k10d two weeks ago. Even the manual focus ring had a stiff gritty feel. It felt as if a bearing ball had cracked. My warranty expires Nov 12, so at least it was the right time for it. As with you, I love the lens.

[Rondec]

I had a 16-50 SDM failure. Took about four weeks for CRIS to get the parts in to replace the motor, but once they did, they got it back to me in short order. Seems to be working really well at this point. Not seeing any hesitation with it at all. Prior, it felt like the motors were trying to move the lens elements but just weren't able, although you could manual focus it without any problem. Hopefully it is good for awhile.

[Ash]

Well, curious thing happened.

I had an SDM failure in late September. I was pretty bummed because I really like the 50-135, it quickly became my favourite lens.

I was going away for most of October, so I had a decision to make, either take the lens into Pentax and not have it for my trips or take it and use it MF only. I decided to take it with me.

Well, lo and behold, I pulled it out of the bag and mounted it, and it worked. Worked flawlessly the entire trip and is still going strong.

I'm tending to think that my initial failure was some type of incorrect mounting on my part, some dust on one of the contacts, or some other "fixable" issue that I didn't notice at the time.

So I'm a happy camper again.

Glad to hear that.
There may be more of this kind of think happening than we realise.

[cwood]

For the record I have had 16-50, 50-135 and 200mm lenses with SDM with no failures although I have never participated in a poll to state that fact.

[philbaum]

I have the DA 300 and the DA 50-135, and use the latter a lot - no problems. I was photographing on Wednesday beside a Pentax friend who has one of the screw drive macros. Couldn't believe how loud it sounded in a small room we were doing portraits in.

I don't subscribe to the notion that electric motors are inherently unreliable. Look how many small electric motors are installed in watches, wall clocks and other applications, and function year after year. There is a push to get new electronic stuff to market so fast that i think many times, quality testing is short-cutted in the drive to beat out other vendors. So the customers sometimes identify the problems. On the other hand, the marketplace often rewards the newest trend in equipment, often foregoing more tested reliable products.

I have no proof but tend to believe those that indicate the percent of failures is probably low. I'm not surprised that lenses with dual screw and SDM mechanisms installed seem to have more of the problems - more mechanism = equals more chance for something to go wrong. I do believe those that report failures; and won't hesitate to report it if it happens to me :-)

Think i'll go out and take some more pics :-)

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Last edited by philbaum; 10-30-2009 at 12:46 PM.

[philbaum]

The question is: Does the fact that the newer model lenses have fewer reported failures merely indicate that they have not yet had time to fail, or also that the SDM system is becoming more reliable as Pentax manufacturing and quality control processes improve and become more stable for the new technology? Time will tell, I suppose. I would expect reliability to gradually improve at least some though.

Charlie,
I believe the latter to be true. For one thing, with the statistics available to Pentax on warranty repairs and repairs in general, its a safe bet that they know exactly how much of a problem this is. Secondly, no sane manufacturer is going to intentionally continue to manufacture defective products, since its a guaranteed way to destroy the credibiity of the brand. So, in general, one will always find a product being fine tuned after initial introduction, unless of course they are manufactured in batch processes, which means that it takes a while to get all the defective parts out of the retail storage areas.

I presently have a DA 300 lens for over a year and a DA 50-135 lens for over 7 months. Both are going strong and work fine. I just took out the DA300 two nights ago and it worked fine after two months of non-use.

I'm not discounting at all that there have been SDM failures, but i hope and think that Pentax has done what any legitimate manufacturer would have done and has fixed the intial manufacturing process or materials. I put a lot of thought into whether i wanted to buy the DA 50-135, and so far its paid off, one very fine pro quality lens. And i used it on a rainy morning the other day while my Canon friend was reduced to carrying an umbrella around for his equipment. I would note that the long hood on the DA 50-135 does an excellent job of keeping rain droplets off the front lens. If it fails i will get it fixed, but so far its all been good.

[hyyz]

In another thread I described the situation I encountered with DA* 50-135mm. Please see the thread here: Observation on DA* 50-135mm AF/MF operations

Does anyone dare to try what I did? I think what I did is logical from user's perspective and shouldn't cause any trouble, but I am less confident after experiencing that.

My feeling of the DA* lens is: although you have 99% chance of not having problem with it, the other 1% of chance may damage the lens.

[Rondec]

My personal feeling is that something about having the dual mode (ability to use either SDM or screw driven depending on the camera) makes the 16-50 and 50-135 more prone to failure. I guess I am banking on the fact that Pentax has hopefully figured out how to fix things so they don't break again, or they will engender a significant amount of ill will.