DA*50-135mm f2.8 SDM Problems / No Problem

SALUKIS97 · 03-19-2010, 08:18 AM

I don't have a 50-135, but I was just getting ready to pull the trigger and buy one. As of yesterday, I couldn't even find one to buy online in the U.S. Sorry if I'm slow, but did I miss something? Has Pentax stopped shipping the 50-135 for the time being due to the SDM issues?

I'm actually glad I couldn't find one yesterday because I would have purchased it. I'm thinking of staying far away from SDM for now.

rustynail925 · 03-19-2010, 09:03 AM

Try adorama, amazon, B&H

SALUKIS97 · 03-19-2010, 09:51 AM

Originally posted by rustynail925

Try adorama, amazon, B&H

Yeah those are the obvious ones and the first places I looked, but as of yesterday, they are all out of stock. Like I said, I couldn't find a single place to buy a 50-135 online in the U.S.

rustynail925 · 03-19-2010, 10:19 AM

Lets hope they are replacing it with the new sdm motor

GoremanX · 03-19-2010, 11:50 AM

I had a thought about this while I was out riding today. I think part of the issue comes from the fact that the DA* line is weather sealed, and to most of us, this implies a certain level of ruggedness. Unfortunately, this isn't the case at all for the DA* 50-135mm. Case in point, the focus mechanism takes over SEVENTEEN turns of the screw-drive to go from close focus to infinity. That's right, OVER SEVENTEEN! Compare this to my F 35-70mm, which requires less than 3 turns. Or the WR kit lens, which requires 5.5 turns. Obviously, by making the focus drive in the 50-135mm use 17+ turns, Pentax drastically reduced the amount of torque needed to drive the focus mechanism, but they probably also made the threads in the mechanism very thin and delicate. Any jam in this movement (whether from heat/cold expansion or vibrations) would cause the micro motor to work harder than intended, eventually burning it out. This may be what causes the occasional funky focusing noises.

Of course, I'm theorizing here. But OVER SEVENTEEN TURNS! That speaks volumes...

snostorm · 03-19-2010, 12:12 PM

I've had the DA* 50-135 since about a month after introduction, and it works fine. I'd estimate about 5000 shots with it on 4 bodies.

Scott

tomtor · 03-19-2010, 01:24 PM

My copy is about 15 months old, no problems, but I don't use it very much.

It's a big lens, I often use my FA77 because it's has ideal dimensions.

aleonx3 · 03-19-2010, 01:27 PM

I also have this lens for over a year now - it is only used indoor for events (wedding, dinner etc.). So far it is doing its job - knock on wood.

rustynail925 · 03-20-2010, 07:28 AM

So far the statistics says about
69% - Good
31% - Trouble

aleonx3 · 03-20-2010, 07:32 AM

Originally posted by rustynail925

So far the statistics says about
69% - Good
31% - Trouble

@Rustynail, I have both DA* 16-50 and 50-135, but I only put in one vote, should I put in two? Also, both of them are good so far, snappy but quiet with SDM motor.

GoremanX · 03-20-2010, 07:33 AM

Originally posted by aleonx3

@Rustynail, I have both DA* 16-50 and 50-135, but I only put in one vote, should I put in two? Also, both of them are good so far, snappy but quiet with SDM motor.

this thread is specifically about the DA* 50-135mm, which I think is a great idea since other threads always deal with every SDM lens. Besides, you can't vote twice.

Conan · 03-20-2010, 08:35 PM

Mine is slightly more than a year old and works perfectly. No need to "wake up" the AF even after storing it.

Itai · 03-20-2010, 08:40 PM

The poll system won't let me answer twice! Why because I had the SDM of the 50-135mm F2.8 fail completely. I sent the lens to repair. They sent me one with a new serial number (3 months later!) and I have not had a problem since.

- Itai
Neoluminance | Fine Art Photography by Itai Danan

rustynail925 · 03-20-2010, 09:22 PM

Voting once and posting that you had 2 failed 50-135 is enough since you cant vote twice

Christopher M.W.T · 03-22-2010, 12:21 AM

Well my SDM hasn't actually failed, I could confirm the motor itself is working, something else went amiss.

View Poll Results: for thos who own or have used the DA*50-135mm f2.8 Hows the SDM?
SDM Problems	25	39.06%
No Problem / SDM works fine	39	60.94%
Voters: 64. You may not vote on this poll

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03-19-2010, 08:18 AM	#16
SALUKIS97 Junior Member Join Date: May 2009 Location: Dawg Country Posts: 41	I don't have a 50-135, but I was just getting ready to pull the trigger and buy one. As of yesterday, I couldn't even find one to buy online in the U.S. Sorry if I'm slow, but did I miss something? Has Pentax stopped shipping the 50-135 for the time being due to the SDM issues? I'm actually glad I couldn't find one yesterday because I would have purchased it. I'm thinking of staying far away from SDM for now.

03-19-2010, 09:03 AM	#17
rustynail925 Veteran Member Join Date: Aug 2009 Location: Philippines Photos: Gallery Posts: 1,551 Original Poster	Try adorama, amazon, B&H

03-19-2010, 09:51 AM	#18
SALUKIS97 Junior Member Join Date: May 2009 Location: Dawg Country Posts: 41	Originally posted by rustynail925 Try adorama, amazon, B&H Yeah those are the obvious ones and the first places I looked, but as of yesterday, they are all out of stock. Like I said, I couldn't find a single place to buy a 50-135 online in the U.S.

03-19-2010, 10:19 AM	#19
rustynail925 Veteran Member Join Date: Aug 2009 Location: Philippines Photos: Gallery Posts: 1,551 Original Poster	Lets hope they are replacing it with the new sdm motor

03-19-2010, 11:50 AM	#20
GoremanX Veteran Member Join Date: Dec 2009 Location: Georgia, VT Photos: Albums Posts: 1,657	I had a thought about this while I was out riding today. I think part of the issue comes from the fact that the DA* line is weather sealed, and to most of us, this implies a certain level of ruggedness. Unfortunately, this isn't the case at all for the DA* 50-135mm. Case in point, the focus mechanism takes over SEVENTEEN turns of the screw-drive to go from close focus to infinity. That's right, OVER SEVENTEEN! Compare this to my F 35-70mm, which requires less than 3 turns. Or the WR kit lens, which requires 5.5 turns. Obviously, by making the focus drive in the 50-135mm use 17+ turns, Pentax drastically reduced the amount of torque needed to drive the focus mechanism, but they probably also made the threads in the mechanism very thin and delicate. Any jam in this movement (whether from heat/cold expansion or vibrations) would cause the micro motor to work harder than intended, eventually burning it out. This may be what causes the occasional funky focusing noises. Of course, I'm theorizing here. But OVER SEVENTEEN TURNS! That speaks volumes...

03-19-2010, 12:12 PM	#21
snostorm Veteran Member Join Date: Oct 2006 Location: Chicago suburb, IL, USA Posts: 1,535	I've had the DA* 50-135 since about a month after introduction, and it works fine. I'd estimate about 5000 shots with it on 4 bodies. Scott

03-19-2010, 01:24 PM	#22
tomtor Veteran Member Join Date: Apr 2008 Location: Netherlands Posts: 382	My copy is about 15 months old, no problems, but I don't use it very much. It's a big lens, I often use my FA77 because it's has ideal dimensions.

03-19-2010, 01:27 PM	#23
aleonx3 Veteran Member Join Date: Jul 2007 Location: Brampton, Ontario Photos: Gallery \| Albums Posts: 3,996	I also have this lens for over a year now - it is only used indoor for events (wedding, dinner etc.). So far it is doing its job - knock on wood.

03-20-2010, 07:28 AM	#24
rustynail925 Veteran Member Join Date: Aug 2009 Location: Philippines Photos: Gallery Posts: 1,551 Original Poster	So far the statistics says about 69% - Good 31% - Trouble

03-20-2010, 07:32 AM	#25
aleonx3 Veteran Member Join Date: Jul 2007 Location: Brampton, Ontario Photos: Gallery \| Albums Posts: 3,996	Originally posted by rustynail925 So far the statistics says about 69% - Good 31% - Trouble @Rustynail, I have both DA* 16-50 and 50-135, but I only put in one vote, should I put in two? Also, both of them are good so far, snappy but quiet with SDM motor.

03-20-2010, 07:33 AM	#26
GoremanX Veteran Member Join Date: Dec 2009 Location: Georgia, VT Photos: Albums Posts: 1,657	Originally posted by aleonx3 @Rustynail, I have both DA* 16-50 and 50-135, but I only put in one vote, should I put in two? Also, both of them are good so far, snappy but quiet with SDM motor. this thread is specifically about the DA* 50-135mm, which I think is a great idea since other threads always deal with every SDM lens. Besides, you can't vote twice.

03-20-2010, 08:35 PM	#27
Conan Forum Member Join Date: Jun 2008 Location: Philippines Posts: 99	Mine is slightly more than a year old and works perfectly. No need to "wake up" the AF even after storing it.

03-20-2010, 08:40 PM	#28
Itai Senior Member Join Date: Sep 2009 Location: Montreal Photos: Gallery Posts: 209	The poll system won't let me answer twice! Why because I had the SDM of the 50-135mm F2.8 fail completely. I sent the lens to repair. They sent me one with a new serial number (3 months later!) and I have not had a problem since. - Itai Neoluminance \| Fine Art Photography by Itai Danan

03-20-2010, 09:22 PM	#29
rustynail925 Veteran Member Join Date: Aug 2009 Location: Philippines Photos: Gallery Posts: 1,551 Original Poster	Voting once and posting that you had 2 failed 50-135 is enough since you cant vote twice

03-22-2010, 12:21 AM	#30
Christopher M.W.T Veteran Member Join Date: Jun 2009 Posts: 1,689	Well my SDM hasn't actually failed, I could confirm the motor itself is working, something else went amiss.