SDM Failure


JAK

Link Posted 08/01/2018 - 14:44
smudge wrote:
The DA*200 is a great lens. I don't think you will be disappointed.

Agreed on that. DA*300 ditto.
John K

doingthebobs

Link Posted 08/01/2018 - 23:10
I have a manual focus DA50-135. Lovely lens but have not got it fixed yet. Rather begrudge paying to get it fixed.

I also have the DA200. This one is full AF and has never had any problem with the SDM. Definitely one of Pentax's best lenses, touched by the angels!
Bob

ronniemac

Link Posted 09/01/2018 - 17:52
Sorry to hear about the problems experienced by Phil, Peter and Philip. I will inevitably post a message here if the SDM motor fails in any of my lenses, it's perfectly understandable that users do this. When everything is fine and ticking along nicely, it's not newsworthy.

On the other hand:

I have been fortunate in that to date, all of my SDM lenses (7) have given good and uninterrupted service. I hope others have similar experience too, and share this information.

I don't post this to gloat, my intention is just to help give a balanced perspective.

davidstorm

Link Posted 09/01/2018 - 20:54
johnriley wrote:
This stems from some early problems with a design fault in a couple of SDM lenses and it was tackled years ago by Pentax. There will always be some failures of any item, but SDM should be as fine as any other focusing system motor. WE haven't heard much about the issue for a very long time.

Sorry John, but I think you are sticking your head in the sand and not being realistic. The SDM problems are not just on early samples, they affect all SDM's, particularly on 16-50 and 50-135 lenses, right up to the present day. This is obvious by the number of reports of second or third failures after motors have been replaced with 'updated' ones.

The users on here are not stupid, we make our own minds up about these things. It's a shame because in other regards these lenses are superb and for me it's worth taking the risk. My 50-135 is on its way out, after having been repaired once with the 'updated' motor that supposedly fixed the issue.........

I think I speak with the majority of view on this subject?

Regards
David
My Website http://imagesbydavidstorm.foliopic.com

Flickr

Some cameras, some lenses, some bits 'n' bobs

johnriley

Link Posted 09/01/2018 - 21:20
The point I would make David is that we don't actually know. We know of some failures (how many?) but we don't know, as ronniemac points out, those that didn't fail as that isn't something that's newsworthy. It's anecdotal as it stands and I wouldn't let it stop me buying an SDM lens. In fact, we have some and they haven't been any different to the DC lenses or the screw drive ones for reliability. But that too doesn't mean anything.

I have some statistics somewhere on the failure rate of VHS video recorders, from about 1980 or so, and in the first year some 35% of them failed for some manufacturers. Now if that happened with SDM lenses we would have a crisis. But we simply don't have the data to judge, and that's the only point I make.
Best regards, John

RobL

Link Posted 09/01/2018 - 22:34
I cannot believe that a firm like Pentax doesnít know or are uninterested in how many repairs have been needed to their lenses, gleaned from numbers of replacement motors supplied. Basic quality control. And presumably some of these have been done under warranty. Of course they may choose not to share such information for commercial reasons but they have a reputation to maintain.

CMW

Link Posted 10/01/2018 - 22:13
Is the following survey the best we have (provided the results are treated as indicative rather than gospel)?

https://www.pentaxforums.com/articles/photo-articles/pentax-sdm-failure-survey-r...

SDM implementation on certain lenses does (did? ó the survey was five years ago) seem to be questionable. The 16-50, 17-70: and 50-135 stand out, not in a good way. There are all sorts of cautions and caveats that need to attach to the figures, but the results of the limited survey donít strike me as inherently implausible.
Regards, Christopher

ChristopherWheelerPhotography

davidstorm

Link Posted 10/01/2018 - 22:23
CMW wrote:
Is the following survey the best we have (provided the results are treated as indicative rather than gospel)?

https://www.pentaxforums.com/articles/photo-articles/pentax-sdm-failure-survey-r...

SDM implementation on certain lenses does (did? ó the survey was five years ago) seem to be questionable. The 16-50, 17-70: and 50-135 stand out, not in a good way. There are all sorts of cautions and caveats that need to attach to the figures, but the results of the limited survey donít strike me as inherently implausible.

Hi Christopher, yes, I'd seen that survey before and although not huge numbers it bears out what the majority say on here about the SDM lenses, particularly the three highlighted as the least reliable in the survey. What's also interesting is that these survey numbers are approaching the 'crisis levels' John has quoted for VHS recorder failures. Now that's an eye-opener, if some SDM lenses approach the unreliability levels of VHS video recorders when they first came out, then indeed there is something to worry about and something that Pentax should have come clean about a long time ago.

Regards
David
My Website http://imagesbydavidstorm.foliopic.com

Flickr

Some cameras, some lenses, some bits 'n' bobs

richandfleur

Link Posted 11/01/2018 - 07:59
Yikes!

Typically surveys are slanted towards the negative (those most aggrieved are more likely to complete a survey) but regardless those numbers don't look good.

RobL

Link Posted 11/01/2018 - 08:14
Contrast with Leicaís response to similar problem:
https://www.getdpi.com/forum/attachment.php?attachmentid=126076&d=1491290969

ilovesaabs

Link Posted 12/01/2018 - 00:30
ronniemac wrote:
Sorry to hear about the problems experienced by Phil, Peter and Philip. I will inevitably post a message here if the SDM motor fails in any of my lenses, it's perfectly understandable that users do this. When everything is fine and ticking along nicely, it's not newsworthy.

On the other hand:

I have been fortunate in that to date, all of my SDM lenses (7) have given good and uninterrupted service. I hope others have similar experience too, and share this information.

I don't post this to gloat, my intention is just to help give a balanced perspective.

I was aware of the issues but that hasn't prevented me from owning 3 SDM lenses (DA*) and repairing 2 (one twice). I've actually looked at it as the lenses completing their PDI (pre-delivery inspection) or major service and coming back from JPSS or Asahi Photo like new. I have had three items repaired because I have been totally inept and careless, and the work done by JPSS has been perfect. Just a shame the motors are unpredictably unreliable.

I have a lens and camera that needs to go to Nikon becase sharpness at 400mm on the new 80-400G VR attached to the D500 is apalling, it wasn't always like that but either the camera or the lens is developing a fault.

I just have to treat this as a sad fact of life
AKA Welshwizard/PWynneJ
Assorted Pentax/Nikon/Mamiya stuff
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