[Blacknight659]

I know SDM failure is common, I just want to know if this is the first signs of failure. I want to convert to Screw Drive if it is.

NOTE: I keep it attached to a camera quite often to avoid the power drain on the capacitor theory

Symptoms:
1.) Squeaked from day 1 I owned it (purchased used from the forums)
2.) Didn't work today on a shoot, had to manual focus
3.) Got home, spun focus all the way around both directions a few times, started working, then wouldn't move at all manually or with the AF button.
4.) Put lens on my Film ZX-7 and it used the screw drive, freed up the manual focus with this.
5.) Put back on K-5iis and SDM started working again.

My question: Is this a failing clutch in the camera or the SDM messing up. I can convert to screw drive, but if the clutch in the manual focus is the problem then I am not really fixing the core problem.


Thanks!

[Paulo]

According to my experience you have faced issue with the SDM motor itself. My copy of da*50-135 was behaving in the same way for several months then suddenly stopped to react for halfpress of the shutter buton.

[Edgar_in_Indy]

I'm no lawyer, but I've seen this kind of sad post so many times that I'm surprised there hasn't been a class-action lawsuit.

According to my experience you have faced issue with the SDM motor itself. My copy of da*50-135 was behaving in the same way for several months then suddenly stopped to react for halfpress of the shutter buton.

Same here. Had it repared and was like new again.
I bought it new and troubles started after 2 years. My best lens up to now but I destroyed it while stopping my son from doing something dangerous. These kids are giving me loads of gray hair
In the end, I will never now how long the repaired sdm would have lasted. Good luck with yours, its such a nice optic.
David

---------- Post added 14th May 2016 at 16:41 ----------

I'm no lawyer, but I've seen this kind of sad post so many times that I'm surprised there hasn't been a class-action lawsuit.

I see such things as nice opportunities to discuss pricing of new purchases
David

[Blacknight659]

Agreed, I was able to Wake mine up, but I am seriously considering selling it for a 70mm prime. I typically shoot 60-90mm when using this lens, I think I could handle 70mm lens also, the lower weight would be nice.

[BigMackCam]

I was able to Wake mine up, but I am seriously considering selling it for a 70mm prime.

The SDM issues have prevented me from buying the 16-50, 50-135 or 60-250 new or used, I'm afraid. I'm sure you'll let the prospective buyer know of the potential issue with your 50-135, but not all sellers are so honest (unfortunately), and I'd have a hard time buying one of these lenses outside of warranty...

[Blacknight659]

The SDM issues have prevented me from buying the 16-50, 50-135 or 60-250 new or used, I'm afraid. I'm sure you'll let the prospective buyer know of the potential issue with your 50-135, but not all sellers are so honest (unfortunately), and I'd have a hard time buying one of these lenses outside of warranty...

Yes, i wouldnt think of selling it without telling about this event. I have it working now, but most people say this is a sign that it will eventually fail. I considered converting it to screw drive for the future buyer, but i haven't made my mind up on that yet.

[mee]

Yes, i wouldnt think of selling it without telling about this event. I have it working now, but most people say this is a sign that it will eventually fail. I considered converting it to screw drive for the future buyer, but i haven't made my mind up on that yet.

Good deal. It seems the common mentality is to 'dump their problems' on someone else and be done with them.. I really hate that level of apathy for another person when I see it (and that's often).

I'm no lawyer, but I've seen this kind of sad post so many times that I'm surprised there hasn't been a class-action lawsuit.

And on the other hand, my bought new in 2009 DA 50-135 and bought used years ago DA 17-70 just keep on trucking. 10's of thousands of images. Easily 200k on the 50-135.

50-135 Classic & Contemporary II

17-70 Made In The USA

But I did just get back my 645 FA 80-160 from KEH repair. They fixed broken guides, it just jammed after the last shoot, couldn't zoom or focus. They returned the bad parts ( metal guides) and it looked to me like bad spot welds. Flat fee repair, same as if they had to replace SDM motors.

My most expensive Pentax gear failures have been a pair of AF 540 FGZ flashes that went belly up, about two years apart and well past warranty. Neither were worth fixing. Four YN560II's in the bag now. Same light and if they die, it's $65.

And so it goes.

[Paulo]

These common problems with SDM made me selling two da* zooms (16-50 and 50-135) and replacing them with limited primes and SMC F135/2.8. Honestly speaking I couldn't be happier then now :-) My concern now is da*300 it is my last SDM lens...

[Blacknight659]

According to my experience you have faced issue with the SDM motor itself. My copy of da*50-135 was behaving in the same way for several months then suddenly stopped to react for halfpress of the shutter buton.

Did you also get the Stuck Manual focus ring? That is the part the concerns me the most. I couldn't fix it until I attached to a screwdirve body, then to SDM body, then keep manually spinning Focus ring until SDM started working.

[Paulo]

No, manual focus worked fine. The problem was in SDM only.

My manual focus was gritty and jamming. I forced it if I recall correctly to no avail. Did not know about the screw drive back then.
David

[Blacknight659]

Just wanted to update everyone. The motor is currently working and seems to be grabbing focus with some certainty. I spoke with Eric at Pentaxs.com. He said this was caused by the SDM, not a guide issue or other mechanical issue. He also said this isn't for sure a sign the SDM is done for, it is a 50/50 chance this will continue to work or break down completely later on.

Either way, I decided Screwdrive conversion is the best for me. Many others say the lens will focus more confidently with this modification. I personally love screwdrive so it should be all good.

[Paulo]

You will be happy with this solution. Screwdrive is the most reliable AF drive Pentax ever made.