Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
02-26-2017, 02:43 PM   #1
Senior Member




Join Date: Mar 2011
Location: Minnesota
Posts: 119
DA* 50-135 AF died

My favorite lens, the DA* 50-135 stopped autofocusing today. What a disappointment for a lens that isn't that old. I read all the warnings about the AF motor being bad but thought I might luck out and not have that problem. For those who have had the same problem where did you get yours fixed and about how much did it cost?

02-26-2017, 03:57 PM   #2
cpk
Site Supporter
Site Supporter
cpk's Avatar

Join Date: Feb 2010
Location: Montreal
Posts: 282
Mine goes to sleep when it is not used. It takes a few minutes of playing with it to wake it up. Have you tried that? Or is the autofocusing dead, dead, dead? If the latter, fix or convert to screw drive are the only options (other than always focusing manually). I've decided to live with my mine as it is.

Last edited by cpk; 02-26-2017 at 04:57 PM.
02-26-2017, 04:16 PM   #3
Site Supporter
Site Supporter




Join Date: Mar 2014
Location: Daphne, Alabama
Posts: 289
My 16-50* & 200*

Uncle Vanya converted both to screw drive for a very modest price. When I use the 16-50 I rarely think about the noise which is not too bad. Funny, I notice the silence of my 300* more than I do the noise from the screw drive. He turned it around quickly and the screw drive is very fast. That might be an option for you. He was doing the conversions for $25 + shipping.
02-26-2017, 04:16 PM   #4
Loyal Site Supporter
Loyal Site Supporter
AquaDome's Avatar

Join Date: Jan 2014
Location: New Carlisle, IN
Photos: Gallery | Albums
Posts: 1,475
I'm sorry to hear that. The DA*50-135 is one of my all-time favorite lenses and one of the reasons (along with the K-3) I'm committed to Pentax for my work camera solution. When mine has acted sluggish after a period of disuse, I attach it to my K-3 and leave them turned on for a few minutes, then "exercise" the lens by turning the focus ring back and forth before I try autofocus again. I'm sure you've tried everything, but in case you want to try again, maybe it will help. (fingers crossed)

When I bought mine, I got a really good deal because the original owner observed a delay in autofocus response after months of disuse and assumed it was on its way out. That was several years ago and it has served me faithfully ever since. If HSM ever failed (knock on wood that it never does), I would not hesitate to send it in for repair. On the other hand, screw-drive conversion wouldn't break my heart and I would absolutely use it as manual-focus-only if it ever came to that. Though it isn't necessarily the most practical lens to use for most of what I do (product photography), I move the tripod further back so I can use the DA*50-135 instead of the Sigma 17-50 whenever I can get away with it. When using focus-peaking, it's manual focus anyway.

Good luck. I hope you get it all sorted out.

02-26-2017, 06:06 PM   #5
Loyal Site Supporter
Loyal Site Supporter
UncleVanya's Avatar

Join Date: Jul 2014
Photos: Gallery | Albums
Posts: 12,908
QuoteOriginally posted by Mr. Ed Quote
Uncle Vanya converted both to screw drive for a very modest price. When I use the 16-50 I rarely think about the noise which is not too bad. Funny, I notice the silence of my 300* more than I do the noise from the screw drive. He turned it around quickly and the screw drive is very fast. That might be an option for you. He was doing the conversions for $25 + shipping.
Thanks for the endorsement! I appreciate the kind words. The fee has increased to $30 but otherwise the service is the same.
02-26-2017, 07:00 PM   #6
Imp
Pentaxian
Imp's Avatar

Join Date: Nov 2014
Location: Washington, DC
Photos: Gallery | Albums
Posts: 1,397
QuoteOriginally posted by UncleVanya Quote
Thanks for the endorsement! I appreciate the kind words. The fee has increased to $30 but otherwise the service is the same.
Double endorsement! Just did it for my 50-135.
02-26-2017, 09:28 PM - 1 Like   #7
Pentaxian
E-man's Avatar

Join Date: Aug 2012
Posts: 512
I haven't had to deal with this as all my autofocus lenses are screw drive but if I were faced with the choice of $300 to replace the motorized drive or a tenth that for an UncleVanya conversion, I know which I'd pick. Hint: I'm a real cheapskate
02-27-2017, 08:45 AM   #8
Senior Member




Join Date: Mar 2011
Location: Minnesota
Posts: 119
Original Poster
Okay, so here's an update. I fiddled with the lens on and off yesterday without success but hoping it would start working. Today I put the lens on my K-5 and at first it was unresponsive. After several tries to get it to autofocus it started working. I put it on my K-3ii and it continues to work. It seems a bit noisier than I remember so I still think something isn't quite right, kind of squeaky. At this point I will just keep using it. If I do have the same problem in the near future I think I will just have it converted. It wouldn't be worth $300 to have the motor fixed and then wonder when it would go out again. I just don't understand why it would stop working and then work again. Any ideas? I'm glad it started working but it does make me nervous thinking about being on a vacation and it stopping again.The pictures I took yesterday turned out surprisingly well using manual focus. I don't use manual focus much anymore so I'm a bit out of practice.

02-27-2017, 08:54 AM   #9
Veteran Member




Join Date: Nov 2014
Location: Edmonton
Posts: 542
if it becomes a nagging issue just convert to screwdrive. you'll actually find that it focuses a bit faster with screwdrive over sdm, and it's guaranteed to work every time.


it's quite typical that these sdms get a bit tired before they die completely. i'm not sure if it's a function of friction in the system or partial binding, but they all seem to do it. guys say that wrapping the focus ring back and forth while activating auto focus helps to "wake them up", but if i had to do that every time i used a lens i'd just put it to screwdrive.
02-27-2017, 10:32 AM   #10
Loyal Site Supporter
Loyal Site Supporter




Join Date: May 2007
Location: Flagstaff, Arizona
Posts: 275
QuoteOriginally posted by Jool Quote
I just don't understand why it would stop working and then work again. Any ideas?
I've not had this experience, so this is just a guess, but ...

In mechanics, there is something called "stiction" (check the wikipedia entry for some more info), wherein it takes more force to get something starting to move than is necessary to keep it moving once it has broken free. I can imagine something like this occurring in a lens that hasn't been used in a while: any lubricants in there could congeal a bit, and you can even have bonding over time between pieces of metal that are in contact with each other. (I can not get some steel setscrews in my jointer loose from the aluminum hub that they are screwed into!! There has been some kind of bonding between the metals over several years.)

The solutions mentioned above: trying a different camera (there may be more power sent to the motor) and manual focusing (breaks the stiction, thanks to the extra force your hand can apply) seem consistent with this.
02-27-2017, 11:14 AM   #11
Veteran Member




Join Date: Sep 2013
Location: Pasadena, CA
Photos: Albums
Posts: 1,125
QuoteOriginally posted by Jool Quote
Okay, so here's an update. I fiddled with the lens on and off yesterday without success but hoping it would start working. Today I put the lens on my K-5 and at first it was unresponsive. After several tries to get it to autofocus it started working. I put it on my K-3ii and it continues to work. It seems a bit noisier than I remember so I still think something isn't quite right, kind of squeaky. At this point I will just keep using it. If I do have the same problem in the near future I think I will just have it converted. It wouldn't be worth $300 to have the motor fixed and then wonder when it would go out again. I just don't understand why it would stop working and then work again. Any ideas? I'm glad it started working but it does make me nervous thinking about being on a vacation and it stopping again.The pictures I took yesterday turned out surprisingly well using manual focus. I don't use manual focus much anymore so I'm a bit out of practice.
Ultrasonic motors have little feet that move on a track of something hard, for example a ceramic one. The distances between the feet and track are very small, so even a small misalignment could mean that motor won't work. I use a similar motor in one of my research instruments (they are MRI compatible) and I run into this issue of motors sticking on a regular basis. What helps in my case is cleaning the ceramic track, but my motors are a lot easier to access. "Exercising" the motors also seem to put them back in shape for some time. If you hear some extra noise, it probably means that the track and feet are not aligned as well as they should be.
02-27-2017, 12:36 PM   #12
Loyal Site Supporter
Loyal Site Supporter
UncleVanya's Avatar

Join Date: Jul 2014
Photos: Gallery | Albums
Posts: 12,908
My view from owning 3 working SDM lenses and one dead lens (now converted) is that I can't predict when SDM will die. I have heard people insist that storing them for a long time without use is a contributor but that doesn't really make sense. New old stock lenses have not seemed to have this issue - only lenses that have been used and then put away. But I also know people who say that they used theirs all the time and it died nevertheless.

What I can confirm from personal experience working on other people's lenses and my own. There are lenses that can be woken up and never seem to go back to sleep. I own a DA* 50-135 that was sold as dead SDM and after a manual exercise of the focus ring for a few minutes it woke up and has never given me any trouble since and I have owned it for several years now. The lens is quiet and while not fast it isn't slower than others I have seen.

What I can also say is that some lenses seem to get slower on SDM as the SDM begins to die. The SDM can sometimes fail to lock focus as it gives out. This is not always accompanied by any unusual sounds but more often than not the lens starts to squeek more when the SDM starts to die.

Conversion to ScrewDrive when a lens has worn out SDM will improve focus speed and accuracy of lock. You may still see front/rear focus and focus missing due to the AF of the system but the overall accuracy seems to improve back to the original performance.

I hope this helps.

---------- Post added 02-27-17 at 02:37 PM ----------

To the OP: for my data - are you a back button af person?
03-05-2017, 07:15 PM   #13
Site Supporter
Site Supporter
KA5TXL's Avatar

Join Date: Mar 2008
Location: Dallas
Photos: Gallery | Albums
Posts: 113
My 50-135 died last year at 1st it wouldn't work with my K1 but worked great with my K20D last summer but by November it wouldn't work on any platform. So I took it to my local shop that I have used for years. They could not even get anyone from Pentax to return their calls or emails. And they sell Pentax???? So they sent it to Precision Camera for me and Precision could not repair it, they had to send it back to Pentax. I finally received it and it work's great but I'm out about $360.
Reply

Bookmarks
  • Submit Thread to Facebook Facebook
  • Submit Thread to Twitter Twitter
  • Submit Thread to Digg Digg
Tags - Make this thread easier to find by adding keywords to it!
accuracy, af, da*, da* 50-135 af, die, focus, k-mount, lens, lenses, pentax lens, people, sdm, sdm lenses, slr lens, time
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
For Sale - Sold: DA* 200, DA*50-135, M 135 3.5, DA-L 50-200, Kiron 2x TC EstimatedEyes Sold Items 7 05-31-2016 08:32 AM
AF speed: DA*50-135 screwdrive vs Sigma 50-150 WillWeaverRVA Pentax SLR Lens Discussion 10 04-08-2016 11:38 AM
For Sale - Sold: Pentax K5,DA*50-135,DA 35 Macro,Sigma 10-20,Tamron17-50 2.8,AF 540 Flash Bigkidneys Sold Items 23 08-24-2011 06:51 PM
For Sale - Sold: Pentax k-7 k7, DA*16-50, DA*50-135, FA 43mm F1.9 Ltd, DA 10-17mm (FISHEYE), AF llhh0223 Sold Items 2 04-08-2011 03:38 PM



All times are GMT -7. The time now is 11:49 AM. | See also: NikonForums.com, CanonForums.com part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
register
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]
Top