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Reliability of the DA* lenses's SDM system

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brosenz

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I've been thinking to add to my lens collection some DA* lenses, like the 16-50, 50-135, 60-250 and 55, I currently have the K-5. My only concern is that I've read multiple articles about reliability issues with the SDM system, and I do not have the option to buy an extended warranty for the lenses, as I did with the K-5, which is now protected for 3 years (1 + 2 years of extended warranty). What are your thoughts ?, It's really hard for me to believe that such expensive lenses are still unreliable (the SDM system) after so many years of production, I would have expected that Pentax would have solved all the problems already, thanks
--
Bernard
 
All seems fine now.
--
Regards Dean - Capturing Creation
N.B. All my Images are Protected by Copyright
 
The SDM lenses work a treat and I've had zero issues with mine. Pick up the 50-135, it's mothers milk so to speak. I can't recommend it highly enough.
 
Davros said:
The SDM lenses work a treat and I've had zero issues with mine. Pick up the 50-135, it's mothers milk so to speak. I can't recommend it highly enough.
Click to expand...
I'm on my third DA* 50-135. I'm also on my third DA* 16-50 (and it may be defective), and my third K20D.

Not all problems with the lenses have involved SDM. Optical misalignment plagues the DA* 16-50. But both of my DA* lenses have had an SDM failure.

Joe
 
I bought my 16-50 and 50-135 in July 2011 new from B&H and I noticed a very conspicuous hand drawn blue pen small circle next to the SN on the outside of both boxes...

Not sure what it means, but sure looks like somebody marked the boxes at the factory indicating that these lenses had some kind of special distinction, like that the SDm had a fix applied or something. At least that's what I like to think!

So far both lenses have been simply superb. Time will tell.

--
Edward

http://www.youtube.com/photouniverse
http://www.edwardthomasart.com
http://www.pbase.com/edwardthomas
 
Davros said:
The SDM lenses work a treat and I've had zero issues with mine. Pick up the 50-135, it's mothers milk so to speak. I can't recommend it highly enough.
Click to expand...
Mine is the other way around. My 50-135 has been back for repair twice (within a year) for the focus system. Optically it is absolutely brilliant.

However, I also have a DA* 16-50 (and I have this lens for over 2 years now) and it has never given up on me. I guess you need to have some luck with them. Judging by the repair tickets of the 50-135 they pretty much have replaced everything except the outside and the glass... I hope it keeps working from now on.
 
I have had my 16-50 lens since May 2010 and my 50-135 since May 2011. So far no problems with either lens.

The complaints you read on forums like this or anywhere else on the internet may be legitimate complaints, however I don't believe they statistically represent reality. I believe the vast majority of SDM lens owners are perfectly happy with their performance.

--
Allan in Colorado, USA
 
aplucini said:
The complaints you read on forums like this or anywhere else on the internet may be legitimate complaints, however I don't believe they statistically represent reality.
Click to expand...
There have been 167 SDM issues reported on this forum that I know about. You can always do the mental exercise of thinking how many posters you think are on the forum, and then how many you think actually own a SDM lens, to come up with an idea of a percentage of failures.

For example, Pentaxforums does post statistics about the number of people using the site, and it appears there are now about 2000 a day on the site. I also think that site has more poster than this site and mostly have for the last few years. I therefore think using the number of poster there for the number of poster here isn't that far a stretch.

I'll go with 2000 posters here for the mental experiment, Not all that 2000 will own a SDM lens. To be very generous, say 50-75% own a SDM lens. If 75% of the 2000 owned a SDM lens then the failure rate would be 11%, 167/1500 * 100 = 11%. If 50% of the 2000 owned a SDM lens then the failure rate would be 17% 167/1000 * 100 = 16.7%.

If you don't like the assumptions above about the number of people posting that own a SDM lens, feel free to supply your own. It is mental experiment after all, so you are free to work the assumptions, but what is know, are the number of lenses reported.

https://docs.google.com/spreadsheet/ccc?key=0AoOE9_TdlzaNdHl0U0ljXzUyR1FvX2pkRU1YZGNFbWc&hl=en_US

Thank you
Russell
 
The problem with this assumption, is its not a random sample, in fact you are far more likely to have lens failures in the sample than not. Also it does not cover the oweners of multiple lenses. Yes some have had multiple failures, but there are also plenty with multiple good lenses too.

Your statistics do show that the early lenses seem to be plagued with problems, but that it now seems to be fixed.
Russell Evans said:
aplucini said:
The complaints you read on forums like this or anywhere else on the internet may be legitimate complaints, however I don't believe they statistically represent reality.
Click to expand...
There have been 167 SDM issues reported on this forum that I know about. You can always do the mental exercise of thinking how many posters you think are on the forum, and then how many you think actually own a SDM lens, to come up with an idea of a percentage of failures.

For example, Pentaxforums does post statistics about the number of people using the site, and it appears there are now about 2000 a day on the site. I also think that site has more poster than this site and mostly have for the last few years. I therefore think using the number of poster there for the number of poster here isn't that far a stretch.

I'll go with 2000 posters here for the mental experiment, Not all that 2000 will own a SDM lens. To be very generous, say 50-75% own a SDM lens. If 75% of the 2000 owned a SDM lens then the failure rate would be 11%, 167/1500 * 100 = 11%. If 50% of the 2000 owned a SDM lens then the failure rate would be 17% 167/1000 * 100 = 16.7%.

If you don't like the assumptions above about the number of people posting that own a SDM lens, feel free to supply your own. It is mental experiment after all, so you are free to work the assumptions, but what is know, are the number of lenses reported.

https://docs.google.com/spreadsheet/ccc?key=0AoOE9_TdlzaNdHl0U0ljXzUyR1FvX2pkRU1YZGNFbWc&hl=en_US

Thank you
Russell
Click to expand...
--
Justin
--------------------------------------------------------
http://www.pentaxphotogallery/justinwatson
 
I think that's about right.

My calculations worked out at 12% for the 16-50 and 14% for the 50-135 over a 3 year period.

Giving around 3% and 3.5% in the first year, Slightly above the average for lens of this type 2-3% but considerably below the 8% that other manufacturers have hit with some of their first generation lens.

But as to whther later versions are more resilient I have two minds on that.

1 Pentax have a poor record fixing anything they can get away not doing, this has gone on so long it traditional. the FA28-70 f2.8 is a good example with it dodgy PZ button.

2 Marking boxes is a Pentax trait to mark re-worked units so the fact some are appearing may represent an engineering revision.

In all this Pentax behave exactly like all the rest they all don't seem to want to shell out for repair unless their livelihoods depend on it ......funny that.

--
My PPG

http://www.pentaxphotogallery.com/home#section=ARTIST&subSection=1471087&subSubSection=0&language=EN
My Photo Stream
http://www.flickr.com/photos/awaldram/
 
justin23 said:
The problem with this assumption, is its not a random sample, in fact you are far more likely to have lens failures in the sample than not. Also it does not cover the oweners of multiple lenses. Yes some have had multiple failures, but there are also plenty with multiple good lenses too.
Click to expand...
My personal experience is 4 SDM lens and zero failures
justin23 said:
Your statistics do show that the early lenses seem to be plagued with problems, but that it now seems to be fixed.
Click to expand...
3 are first generation and 2 of the worst 16-50,50-135

So if I report my own experience I can see nothing wrong with SDM it reliable and consistent :)
justin23 said:
--
Justin
--------------------------------------------------------
http://www.pentaxphotogallery/justinwatson
Click to expand...
--
My PPG

http://www.pentaxphotogallery.com/home#section=ARTIST&subSection=1471087&subSubSection=0&language=EN
My Photo Stream
http://www.flickr.com/photos/awaldram/
 
...or Silent Drive Motor. I have a bunch of each class and so far no failures. Knock wood. My 55-300 sounds like a garbage disposal though.

Cheers. ernie
 
Russell Evans said:
aplucini said:
The complaints you read on forums like this or anywhere else on the internet may be legitimate complaints, however I don't believe they statistically represent reality.
Click to expand...
There have been 167 SDM issues reported on this forum that I know about. You can always do the mental exercise of thinking how many posters you think are on the forum, and then how many you think actually own a SDM lens, to come up with an idea of a percentage of failures.

For example, Pentaxforums does post statistics about the number of people using the site, and it appears there are now about 2000 a day on the site. I also think that site has more poster than this site and mostly have for the last few years. I therefore think using the number of poster there for the number of poster here isn't that far a stretch.

I'll go with 2000 posters here for the mental experiment, Not all that 2000 will own a SDM lens. To be very generous, say 50-75% own a SDM lens. If 75% of the 2000 owned a SDM lens then the failure rate would be 11%, 167/1500 * 100 = 11%. If 50% of the 2000 owned a SDM lens then the failure rate would be 17% 167/1000 * 100 = 16.7%.

If you don't like the assumptions above about the number of people posting that own a SDM lens, feel free to supply your own. It is mental experiment after all, so you are free to work the assumptions, but what is know, are the number of lenses reported.

https://docs.google.com/spreadsheet/ccc?key=0AoOE9_TdlzaNdHl0U0ljXzUyR1FvX2pkRU1YZGNFbWc&hl=en_US

Thank you
Russell
Click to expand...
Russel,

167 total failures that you know about and your dividing by 2000 people PER DAY. This presuposses that there are 167 FAILURES PER DAY.

Meaningless. Sorry.
--
Edward

http://www.youtube.com/photouniverse
http://www.edwardthomasart.com
http://www.pbase.com/edwardthomas
 
Also note that the first 3 SDM lenses (16-50,50-135,55) are not particulary fast to focus. That seems to be much improved with 300 and 60-250. If you plan to shoot sports, DA60-250 is better bet than 50-135.

Regarding failure rate, that seems to be in line with statistics made by lensrentals on Canon, Nikon or Sony products. Even better lately.
--

Through a Pentax Limited prime things may appear sharper than they actually are...
http://www.pentaxphotogallery.com/jaroslavhoudek
 
For what it's worth, I bought a DA* 60-250mm from Amazon last year (Oct.) and the SDM was semi-to-non-functional out of the box. It took about 20 secs for the lens to focus.

I immediately sent it back, and received a replacement. The replacement has worked perfectly for the last year.

-j
 
My only DA* lens is the 200mm. Got it less than 1 year ago and had to send it in for repair of the SDM 2 months ago.

The focus motor is a questionable design, and don"t assume that getting a new lens will solve the problem.
I would still by the lens, but wish they would fix this ongoing problem.

Pete
 
Here is the story on "Russel Evans". Never owned a Pentax SDM lens, doesn't appear to own a camera, known as an "SDM statistics" troll. A great candidate to laugh at and then put on ignore.

I've owned the DA*55 and DA*200 - never had an issue with SDM.
Russell Evans said:
I don't own any of the things I talk about, but I try so hard, why won't you listen?!?!
Click to expand...
--
My Website
http://www.andrewallenphoto.com

My Pentax Street Gallery - Arranged By Lens Used
http://photobucket.com/andy_allen
 
I love my Pentax and have been delighted with my primes. I recently upgraded to a 16-50 from a Sigma 17-70 because I wanted the 2.8 throughout and decided to go with the real thing. The quality of the lenses is night and day. I cannot believe how poorly made the Sigma looks now.

The lens was a delight to use - tack sharp at both ends after adjusting +10. I used it steadily for week while visiting family in Florida and then took it off for the trip back. When I put it back on the camera it was dead as a door nail and interfered with the functioning of my K5, which makes me think the failure was related to a short, rather than a motor failure per se.

Just replaced it at B and H yesterday and am not sure that I will stay with the new one, since it is ever so slightly front focusing at the wide end, even at +10. I use a Lens Align, so no guess work here. I want to get some real world use, to see if it makes a difference.

That said, even if I have to go back and get a third or even a fourth lens, I will stick with the lens because it is so far superior to the Sigma.
 
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