How to Fix a Broken SDM Lens (Sometimes)

[miserere_mei]

<p>For what it's worth, this was posted by Eckinator, a member of the PDML, who spoke with Pentax Europe's former technical service manager and asked him about the SMD issues:</p>

<blockquote>

<p><em>not every perceived failure necessarily is one. SDM motors hold a charge which depletes after prolonged (months) non-use. Once discharged, the lens will no longer focus. The charge takes up to two minutes to rebuild, i.e. the lens needs to be left alone for that time while connected to a powered on camera. At times, that may still not be enough to initially overcome mechanical stiction from the long sitting period.</em></p>

</blockquote>

<p>Read more from this conversation on SDM <a href="http://www.mail-archive.com/pdml@pdml.net/msg564506.html">here.</a></p>

[shots worth sharing]

<p>It's pretty astounding, after all the SDM angst, that this little tidbit comes to light--and leaked by a former service manager no less. Now, there's no way of knowing what percentage of the SDM failures this could explain (and the symptoms I've seen described don't seem to be consistent with this sort of issue) but, for Pete's sake, why would Pentax not share this information with it's customers?! </p>

[davidmantilla]

Wow, I wonder if that's what happened to me... had been a few months since I used the lens and it stopped working... i thought the electronic contacts were loose... ... ended up sending back for repairs. I better start using the lens now that I know this could possibly happen. They should definitely add this to the User's Manual for the few of us who actually read those things.

[r.t. dowling]

<p>So, basically what this "Eckinator" person is saying is that Pentax SDM lenses will "go bad" just from sitting on a shelf for a while?</p>

<p>Wow.</p>

[rparmar]

<p>This is insane. Can someone in Japan talk to Hoya/Pentax and confirm this?</p>

[r.t. dowling]

<p>Everything like this should be taken with a grain of salt. Some people are claiming that they heard from Pentax that certain lenses will be discontinued; others are claiming that they heard from Pentax that those same lenses will <em>not</em> be discontinued. Only Pentax knows for sure. Until they release an official statement, it's all just hearsay.</p>

[mountainvisions]

<p>just a note there is a secondary way to fix sdm non failure failure.<br /><br />if the lens stops focusing, rotate the focus ring from infinity to close focus and back several times. It seems like some of the failures are temporary and a result of the clutch engagement. I did this to mine once when it briefly stopped focusing about 2 years ago and never had a problem since.</p>

[personalphotos]

<p>Now this is a question I would have asked Ned during his "interview". When are you releasing SDMII?</p>

[andrewg_ny]

<p>Well, "SDMII" *might* be "DC" but I don't think you'll hear Pentax release an official statement on it.</p>

[ukhov]

<p>it all no good TAIWAN bogus </p>

[mountainvisions]

<p>Yury,</p>

<p>I am curious if you could expound upon that thought?</p>

[ukhov]

<p>The rule of new product,not even thought-simply stop count on it long time ago</p>

[thomas_janik]

<p>Hi All:<br>

This thread caught my attention since I have one SDM lenses (17-70) which stopped autofocusing about a month ago. I tried the fixes suggested, no luck. What's interesting is that when that lens is mounted on the camera, "MF" appears in the viewfinder, regardless of the camera settings; replace the lens with functioning (screw drive) lens and everything is fine. My question: is this a failure in the lens, or the body which is not recognizing an SDM lens? I can't test it with another lens, since I don't have access to another SDM lens.</p>

[andrewg_ny]

<p>Thomas, if the lens otherwise works (aperture & focal length transmitted to body, etc.), you might look into the extra 'power zoom' contacts that are used only by SDM...wonder if they're clean?</p>

<p>Do you have any access to a second body you can try the lens on?</p>

[thomas_janik]

<p>Thanks for the reply Andrew. Cleaning the contacts was the first thing I tried and I have no other body available with which to test the lens. I'm wondering if anyone else who has had a SDM failure has seen "MF" appear in the viewfinder, if not, it's possibly a camera issue.</p>

[scott_fraser4]

<p>Question: if not using a SDM lens for a couple of months kills the charge and renders it useless, shouldn't it be the case that almost all new lenses are dead on arrival due to this? It can take a long time between being built and ending up in your hand.</p>

<p>If it takes 8months to kill the charge, and you are using the lens that length of time, I don't think it's a big problem!</p>

<p>I suspect that this should be chalked up as a folk tale, unless someone can give concrete evidence.</p>

[orly_andico]

<p>SDM motors are piezo-electric, not electrostatic. This story doesn't sound very scientific..</p>