50-135 SDM not working


Dogwalker

Link Posted 29/04/2014 - 22:15
Hi Everybody, I have a problem with my 50-135 SDM motor, I foolishly forgot to run the AF motor, And left it for six weeks unused, It was working last time i used it, Anyway i was wondering if any of you know how to wake the motor up. Thanking you all beforehand if you can help. Regards Bob.

davidstorm

Link Posted 29/04/2014 - 22:51
I think you could try turning the focus mechanism with a small screwdriver via the screwdrive slot, this seems to have worked for some people. I wonder what causes the SDM motors to fail like this?

Maybe someone can give us a technical reason.

Regards
David
Flickr

Nicola's Apartments, Kassiopi, Corfu

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

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CMW

Link Posted 29/04/2014 - 23:48
On Pentax Forum in the US a presumably unofficial interview with a Pentax engineer went as follows:

"Q: Our survey found that the Pentax DA* 16-50mm and 50-135mm were the most prone to SDM failure. Do you know why this was?
A: One could say that the AF components used in these lenses was prone to failure from the get-go due to their design. The 16-50mm and 50-135mm lenses share the same circuitry and motor, which is why they both have such a high failure rate. Other SDM lenses don't fail as much.

Q: Has this SDM quality control issue been resolved?
A: Yes. The components used in the 16-50mm and 50-135mm lenses have been redesigned, and all lenses produced in 2012 or later should no longer fail."

Tiny motors are used in moving the lenses and that exchange suggests that the original versions were simply not up to their allotted task over the longer term.

David's suggestion above is worth trying, and it is also worth cleaning the contacts thoroughly (that started an SDM motor of mine that I thought had failed).

It is possible to ignore the SDM motor and get the camera's screw drive to work the 50-135 but that involves altering internal settings and is probably only for the brave (or care-free). Safer, I imagine, to send the lens for repair if it can't be woken up.
Regards, Christopher

ChristopherWheelerPhotography

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stevejcoe

Link Posted 30/04/2014 - 06:53
If you have an old Pentax AF film body, give the lens a good exercise using that. Point the lens up and down while focusing, let gravity help to overcome 'stiction' problems. Finally make sure that you have a freshly charged battery in your DSLR, when you try to wake it up.

Regards Steve

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cabstar

Link Posted 30/04/2014 - 13:21
If you do need a repair pay for pentax plus membership to the forum and this will give you 20% of repairs at Pentax repairers JP solutions, the repair will replace the SDM with the latest motor which should remove the failure possibility substantially.
PPG Wedding photography Flickr
Concert photography

Currently on a Pentax hiatus until an FF Pentax is released

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Mike-P

Link Posted 30/04/2014 - 13:35
cabstar wrote:
If you do need a repair pay for pentax plus membership to the forum and this will give you 20% of repairs at Pentax repairers JP solutions, the repair will replace the SDM with the latest motor which should remove the failure possibility substantially.

It also makes it a bloody sight faster to focus
. My Flickr

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Gamka

Link Posted 30/04/2014 - 13:59
stevejcoe wrote:
If you have an old Pentax AF film body, give the lens a good exercise using that. Point the lens up and down while focusing, let gravity help to overcome 'stiction' problems. Finally make sure that you have a freshly charged battery in your DSLR, when you try to wake it up.

Regards Steve

I wish! Have tried that using a *istD. Up/down, panning slightly to get short sharp changes and every other way I could think.

I am seriously thinking of a letter to Pentax saying that even out of warranty the item is "not fit for purpose" and that by redesigning the motor they must have realised there was a problem and a recall should have occurred.

tyronet2000

Link Posted 30/04/2014 - 18:21
I wonder how many potential buyers have been put off by these threads regarding both the 16-50mm and the 50-135mm
Regards
Stan

PPG

tomkeet

Link Posted 30/04/2014 - 19:12
You could try "RiceHigh's Pentax Blog" link .Might be a quick cheap fix!! Or even disable SDM.
Regards
Tom

K-3's, K-3II.
SMC PENTAX-DA FISH-EYE 1:3.5-4.5 10-17mm ED [IF], SMC PENTAX-DA* 1:2.8 16-50mm ED AL [IF] SDM,
SMC PENTAX-DA 1:4 15mm ED AL Limited, SMC PENTAX-DA 1:3.2 21mm AL Limited,
SMC PENTAX-F 1:2.8 28mm, SMC PENTAX-FA 1:2 35mm AL, SMC PENTAX-FA 1:1.4 50mm,
SMC PENTAX-D FA MACRO 1:2.8 100mm WR, SMC PENTAX-DA* 1:4 300mm ED [IF] SDM, SMC PENTAX-FA* 1:5.6 400mm IF & ED,
HD PENTAX-D FA 1:4.5-5.6 150-450mm ED DC AW, HD PENTAX-DA 1:5.6 560mm ED AW,
SMC PENTAX-FA* 1:5.6 250-600mm ED[IF],
HD PENTAX -DA 1.4x AW AF REAR CONVERTER,
PENTAX AF160FC Auto Macro Ring Flash.

https://pentaxphotogallery.com/artist-gallery/?artist_id=20168301

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Dogwalker

Link Posted 01/05/2014 - 14:03
Thank you everybody for your comments and tips, No joy yet,

Regards Bob.

stephenparfitt

Link Posted 01/05/2014 - 14:36
tyronet2000 wrote:
I wonder how many potential buyers have been put off by these threads regarding both the 16-50mm and the 50-135mm

Certainly has made me think about the wisdom of investing in these lenses.

bforbes

Link Posted 01/05/2014 - 14:39
tyronet2000 wrote:
I wonder how many potential buyers have been put off by these threads regarding both the 16-50mm and the 50-135mm

As far as I'm concerned you can add the Pentax 17-70 to that list
Barrie
Too Old To Die Young

http://www.pentaxphotogallery.com/artists/barrieforbes
https://www.flickr.com/photos/189482630@N03/

Marselus

Link Posted 01/05/2014 - 14:45
Mi 16-50 also needed to be woke up before use by just refocusing it for a few times manually while attached to the camera.
Try it you never know.

McBrian

Link Posted 01/05/2014 - 14:56
Marselus wrote:
Mi 16-50 also needed to be woke up before use by just refocusing it for a few times manually while attached to the camera.
Try it you never know.

It still does

With the K5ii and the K3 and quick trip in to LV and using the back AF buttom seems to wake it up, might be worth a try with the 50-135.
Cheers
Brian.
LBA is good for you, a Lens a day helps you work, rest and play.
Last Edited by McBrian on 01/05/2014 - 14:57

cardiffgareth

Link Posted 29/11/2016 - 23:24
CMW wrote:
On Pentax Forum in the US a presumably unofficial interview with a Pentax engineer went as follows:

"Q: Our survey found that the Pentax DA* 16-50mm and 50-135mm were the most prone to SDM failure. Do you know why this was?
A: One could say that the AF components used in these lenses was prone to failure from the get-go due to their design. The 16-50mm and 50-135mm lenses share the same circuitry and motor, which is why they both have such a high failure rate. Other SDM lenses don't fail as much.

Q: Has this SDM quality control issue been resolved?
A: Yes. The components used in the 16-50mm and 50-135mm lenses have been redesigned, and all lenses produced in 2012 or later should no longer fail."

Tiny motors are used in moving the lenses and that exchange suggests that the original versions were simply not up to their allotted task over the longer term.

David's suggestion above is worth trying, and it is also worth cleaning the contacts thoroughly (that started an SDM motor of mine that I thought had failed).

It is possible to ignore the SDM motor and get the camera's screw drive to work the 50-135 but that involves altering internal settings and is probably only for the brave (or care-free). Safer, I imagine, to send the lens for repair if it can't be woken up.

Sorry to resurrect an old thread but is this the case still with the 50-135mm? Post 2012 lenses are modified so don't have this issue??

If so, is there a serial number list so you can check the manufacturer date of the lens?
Gareth
Welsh Photographer

My outfit: K1 gripped - Pentax D FA 24-70mm - Sigma 70-200mm OS HSM - Pentax modified DA* 60-250mm f4 - Irix 15mm Firefly - Pentax FA 35mm - FA 50mm - Tamron SP 90mm macro - Pentax AF 540 FGZ II

My Flickr
My PPG
My 500px
Last Edited by cardiffgareth on 29/11/2016 - 23:25
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