Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
09-06-2015, 01:09 AM   #16
Loyal Site Supporter
Loyal Site Supporter
UncleVanya's Avatar

Join Date: Jul 2014
Photos: Gallery | Albums
Posts: 15,973
With my 50-135 I just put it in manual focus on the camera and rapidly RAPIDLY spun it back and forth for a few minutes.

09-06-2015, 03:35 AM   #17
Veteran Member
channeler's Avatar

Join Date: Jun 2007
Location: Northwich Cheshire England
Photos: Gallery
Posts: 1,008
QuoteOriginally posted by UncleVanya Quote
With my 50-135 I just put it in manual focus on the camera and rapidly RAPIDLY spun it back and forth for a few minutes.
Did you put the lens in manual focus as well or was it in AF?

Paul
09-06-2015, 07:21 AM   #18
Loyal Site Supporter
Loyal Site Supporter
UncleVanya's Avatar

Join Date: Jul 2014
Photos: Gallery | Albums
Posts: 15,973
QuoteOriginally posted by channeler Quote
Did you put the lens in manual focus as well or was it in AF?

Paul
I honestly don't remember. Sorry.
09-06-2015, 07:26 AM   #19
Pentaxian
cmohr's Avatar

Join Date: Apr 2011
Location: Brisbane. Australia
Photos: Gallery
Posts: 1,407
I have basically done this with my 50-135 in the past, and yes, it works.

12-04-2015, 03:49 PM   #20
Site Supporter
Site Supporter




Join Date: Aug 2014
Posts: 407
well, just tried this on my 16-50 from keh and the sdm is still dead. I suppose it will be going back next week then. Sad day, I thought it was a good bargain. I could convert to screw drive, but I wanted silent focus. I guess I may get the Sigma instead now.
12-19-2015, 01:28 PM   #21
Veteran Member




Join Date: Aug 2013
Location: Chicago, IL
Posts: 439
Is this only helpful when the green light is on?

Last edited by Newtophotos; 12-19-2015 at 01:35 PM.
12-30-2015, 06:18 AM   #22
Veteran Member
LeDave's Avatar

Join Date: Jun 2009
Location: Minneapolis - St. Paul
Photos: Gallery
Posts: 3,044
Original Poster
QuoteOriginally posted by Newtophotos Quote
Is this only helpful when the green light is on?
Nope, the green light is just optional, it's useful because you'll know when it is done trying to focus so that you release the AF button and hold it again for how longer the green light is. But once you get used to this, you won't need to follow the green light thing anymore. As long as it's trying to focus, that's all it matters regradless of green light or no light.

QuoteOriginally posted by willskywalker93 Quote
well, just tried this on my 16-50 from keh and the sdm is still dead. I suppose it will be going back next week then. Sad day, I thought it was a good bargain. I could convert to screw drive, but I wanted silent focus. I guess I may get the Sigma instead now.
How long have you tried doing this for? The longest it took me to revive my 16-50 was about 5 minutes.

Last edited by LeDave; 12-30-2015 at 06:23 AM.
12-30-2015, 01:25 PM   #23
Site Supporter
Site Supporter
RobA_Oz's Avatar

Join Date: Nov 2008
Location: Tasmania, Australia
Photos: Gallery
Posts: 5,597
I used this technique successfully several times on my 16-50 a couple of years ago, but it eventually didn't revive it, so I moved to the dismantling method to unstick the drive motor. What I did learn from the latter, is that it is the motor itself that sticks, and not anything else in the drive train, so the early speculative comments in this thread are incorrect.

In the end, the periods between successive dismantlings got smaller and smaller, so I converted it to screw drive, and damn the extra noise, which I don't find intrusive anyway. The OP's technique still works on my 50-135, though.

12-31-2015, 05:17 AM   #24
Veteran Member
Papa Lazarou's Avatar

Join Date: Mar 2013
Location: Bletchley, Buckinghamshire, UK
Posts: 340
To the OP, thanks so much for the tip. I haven't used my 16-50 in 6 months. Got it out of the bag and it wasn't focussing. Replaced the SDM motor only 12 months ago. Your tip worked a treat. Works like a dream. Bravo!
02-25-2016, 10:00 PM - 2 Likes   #25
Pentaxian
johnmflores's Avatar

Join Date: Apr 2009
Location: Somerville, NJ
Photos: Gallery | Albums
Posts: 5,295
SUCCESS!!!!

After doing as described for several minutes, I finally saw the lens come to life. IT'S ALIVE! But it was slow as molasses and not consistent. I kept at it, and then refined the process:
  1. Set to AF.C
  2. Put camera on table or lap and aim at distant object (~infinity or across the room)
  3. Manually move focus to 1'
  4. Press and hold AF button
  5. As motor moves lens to infinity, manually move the focus back to 1'
  6. Do this for several minutes, sometimes releasing AF and starting over
  7. You can feel when the manual rotation to 1' would "catch" the AF motor as it tried to move to infinity, sometimes it felt like it would catch the motor and wind it the other way
  8. Eventually, the AF motor got faster as it moved to infinity

I then reversed the exercise, focusing on a near object, manually moving the AF to infinity, and then pressing AF, working against the motor as it tried to move to 1'.

The 16-50 went from molasses to maple syrup to olive oil in a matter of minutes. I imagine if I do it for another hour or so it would become a Canon L-lens!

Thanks OP! My hero!
02-25-2016, 11:15 PM   #26
Pentaxian




Join Date: Jun 2009
Location: GMT +10
Photos: Albums
Posts: 11,671
I really hope someone in Ricoh has been reading all these 'DIY SDM fix' threads, and that someone in Ricoh lens engineering has learnt some good design lessons from the experience of SDM users/victims. Whatever Pentax were doing with SDM, they were doing it wrong.
02-26-2016, 05:30 AM   #27
Site Supporter
Site Supporter
RobA_Oz's Avatar

Join Date: Nov 2008
Location: Tasmania, Australia
Photos: Gallery
Posts: 5,597
QuoteOriginally posted by rawr Quote
I really hope someone in Ricoh has been reading all these 'DIY SDM fix' threads, and that someone in Ricoh lens engineering has learnt some good design lessons from the experience of SDM users/victims. Whatever Pentax were doing with SDM, they were doing it wrong.
You'd hope so, wouldn't you? Given that the problem hasn't appeared from the first, but only after a fair number of actuations (except, perhaps, in a small number of cases) I think the design process was probably inadequate at the prototype testing phase. A more rigorous testing procedure should minimise the chances of a similar failure, mainly more units involved for a greater number of actuations.
03-05-2016, 09:55 PM   #28
Veteran Member
LeDave's Avatar

Join Date: Jun 2009
Location: Minneapolis - St. Paul
Photos: Gallery
Posts: 3,044
Original Poster
Hey guys, I recently found another way to do it, I edited my first post. If this works on you guys too, then this is the easiest and most basic way to jumpstart the SDM. Here's what the update said,

3/5/2016 Update:

Hey guys, I found another cheap way to quick fix the SDM problem. You just hold the AF button down for a couple of seconds and let go, then you hold the AF button down for a couple of seconds and let go, repeat, repeat, and repeat until it starts to move and focus again.
03-06-2016, 12:15 AM   #29
Site Supporter
Site Supporter
RobA_Oz's Avatar

Join Date: Nov 2008
Location: Tasmania, Australia
Photos: Gallery
Posts: 5,597
…which is what a number of us do already, as noted in the original SDM fix threads. Given the length of those threads, though, I don't condemn you for not reading through each and every post.

PS: that worked, too, for a while, with my DA*16-50, but, like the spinning focus ring method, its effectiveness tended to fade with use and time, so don't be surprised if that happens with yours, too.
03-06-2016, 04:42 AM   #30
Veteran Member
channeler's Avatar

Join Date: Jun 2007
Location: Northwich Cheshire England
Photos: Gallery
Posts: 1,008
QuoteOriginally posted by LeDave Quote
Hey guys, I recently found another way to do it, I edited my first post. If this works on you guys too, then this is the easiest and most basic way to jumpstart the SDM. Here's what the update said,

3/5/2016 Update:

Hey guys, I found another cheap way to quick fix the SDM problem. You just hold the AF button down for a couple of seconds and let go, then you hold the AF button down for a couple of seconds and let go, repeat, repeat, and repeat until it starts to move and focus again.
Hi, I found a variation on this (which I had come across in another post) worked for me for my DA*300. I pointed the lens horizontal, then down, then up, each time half pressing the shutter button to try to get autofocus. It took a long time to get the sdm back to life but it suddenly kicked in. I don't know it is was about trying to use gravity or just giving the autofocus alternative points. I had tried the other techniques before this without success ie: rapidly moving the lens back and forth in manual focus mode, keeping the lens cap on, pressing AF and spinning the focus. The first time I had a problem the lens had been stored in a camera bag for a couple of months. After I managed to revive it and left it for a few weeks I had the same seizure/sticking problem, but the lens revived more quickly after applying the above method. If I just leave it a day it will stick initially but revives very quickly. I don't think the lens is working quite as quietly as it did when first bought. I don't know what the fundamental problem is. I presume there is some kind of lubrication inside the lens mechanism. Can it dry up? The first time I experienced any problems I had taken the lens to France (so in a consistently warmer, but on that trip also wetter, climate) on holiday for a few weeks. I did not get the lens out of the bag. A few weeks after my return I had the first SDM problem. Anyhow, I am just going to try to exercise the lens regularly every day or two and see if that improves things.

Paul
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!
af, auto, button, clutch, degrees, focus, k-mount, lens, light, mechanism, pentax lens, pentax lenses, procedure, sdm, shift, slr lens, thread
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
No more SDM failures? -Pentax smc DA* 50-135mm F2.8 ED (IF) SDM Taviali Pentax SLR Lens Discussion 12 03-13-2012 10:01 AM
Are SDM Failures a Thing of the Past? Parallax Pentax SLR Lens Discussion 15 11-02-2010 12:58 AM
Is there a way to keep DA*16-50mm SDM working for a LONG time? shang Pentax SLR Lens Discussion 5 07-29-2010 06:33 PM
SDM Failures and Warranty Issues (Factory and Aftermarket) sandpipe Pentax SLR Lens Discussion 7 07-27-2010 09:58 AM
K10D - has anyone found a way to trigger optical slave with onboard flash? Hornet Pentax DSLR Discussion 19 12-01-2008 03:27 PM



All times are GMT -7. The time now is 04:31 PM. | 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