[cpk]

Forgive me if we've discussed this before, but what was your magic procedure for waking up the SDM on this lens? I'd like to have another go at waking up my 60-250. Serial number is 9229636. I've tried one procedure I ran across somewhere, but no luck.

This is what I did for my 50-135. It is quoted from another post of mine. It does require, however, that your lens will wake up and start focussing in a normal fashion just by trying it out continuously for a while:

"Exercise the lens regularly. My 16-50 has always been okay for SDM focusing, but not my 50-135. Neither lens was used that often for a number of years, and the 50-135 would require me playing with it for 15-30 minutes just to get the SDM to work. Last year I spent about a month taking it out of storage almost every day and, once the focusing started to work, exercised it by focusing on different distances in my apartment and through the windows for 30 minutes or so. Eventually it would focus immediately during these daily sessions. Now I do this exercising every two or three weeks.

"I should add that my current exercising of the lens is for only 5 minutes or so to ensure the focusing is still working right away. The key is to keep using the lens even if only to exercise it."

Read more at: Convert SDM to screw drive for K-70? - PentaxForums.com

[jddwoods]

I have 3 SDM lenses:
oldest: DA* 200, SDM may need a few seconds to wake up if lens has been sitting around for more than 2 months, but then works fine.
DA 17-70, SDM worked for about 4 years then died. I have tried all the wakeup/exercise options on this lens but nothing worked.
newest: DA*300, no SDM problem, works fine.

My other two silent focus lenses are DA 16-85 and 55-300 PLM and the autofocus is perfect on both, but they are not SDM.

[caliscouser]

Supposedly there were updates to the SDM around 2012 for the 16-50 and 50-135 that should reduce failure.

I'm not sure if anyone has one manufactured after that date that failed. It would be good to know.

Pentax Engineer on SDM Failure and Pentax DC - Photokina 2012 | PentaxForums.com

[jddwoods]

Supposedly there were updates to the SDM around 2012

I recall seeing this too on this forum a few years ago. My DA 17-70 and DA* 300 were both purchased after 2012.

[mikesbike]

From what I understand, the DA* 60-250mm can be converted for FF use, but cannot be converted to screw-driven operation should its SDM fail, and likewise with the DA* 55mm. From reports I've read, conversion to screw-driven AF operation for lenses like the DA* 200mm, 300mm, and 50-135mm have resulted in faster AF compared with the original SDM AF. But this might depend on the camera body supplying the power and technology for screw-driven AF. I have noticed improved AF performance with my screw-driven lenses when used on my KP bodies. I have 2 SDM lenses, the DA* 200mm f.2.8 now for around 5 years, and 50-135mm f/2.8 now for around 10 years, neither of which do I exercise regularly, and use mainly when I need the greater aperture range with highest quality. I love them both. So far, they work fine (knocking on wood).

[jatrax]

The 60-250 is very easy converted to FF. I have done it recently, and it is perfect at FF, really no dark corners visible

I converted my original 60-250 to FF, one of the earliest ones done actually. But I still found the corners dark. Not unacceptable but still needing correction at some focal lengths.

I sold it because the focusing speed was slow enough I found it irritating. So I am now using my Pentax-F 70-210. Which is also somewhat irritating....

[SunValley]

Both my 16-50 and 50-135 failed 4 years ago. On my K-30 they would just freeze up, or go only one direction and finally no movement at all. I was ready to have them converted when I just decided to put them on my K-5 with a fully charged D-Li90 battery. It woke them up! The 16-50 has fully recovered but I still put it back on my K-5 from time to time. The 50-135 needs waking up with the K-5 every month. It's been four years now and I'm still enjoying the silent sdm crossing my fingers.

[UncleVanya]

From what I understand, the DA* 60-250mm can be converted for FF use, but cannot be converted to screw-driven operation should its SDM fail, and likewise with the DA* 55mm.

That is correct. Only the DA* 16-50 / 50-135 / 200 / 300 and 60-250 had the necessary hardware for conversion (screw drive and sdm). They were built that way due to when they were introduced to the lineup. The existing camera base was mostly screwdrive and only the newest bodies had SDM. So these premium lenses were made to go either way - with a bias towards SDM. If the camera detected (from asking the lens) SDM - then it used SDM. Even if SDM is dead. The 60-250 has proven to be elusive. I have never found anyone who converted it correctly - although there were rumors of a Russian conversion operation but nothing conclusive was even shared - files from the lens did not work elsewhere and nothing odd was found in that lens file - so it may be a fluke or ? In any case the other SDM lenses are not equipped with screw drive ports and cannot be converted.

From reports I've read, conversion to screw-driven AF operation for lenses like the DA* 200mm, 300mm, and 50-135mm have resulted in faster AF compared with the original SDM AF. But this might depend on the camera body supplying the power and technology for screw-driven AF. I have noticed improved AF performance with my screw-driven lenses when used on my KP bodies. I have 2 SDM lenses, the DA* 200mm f.2.8 now for around 5 years, and 50-135mm f/2.8 now for around 10 years, neither of which do I exercise regularly, and use mainly when I need the greater aperture range with highest quality. I love them both. So far, they work fine (knocking on wood).

My own opinion is different. I have converted many copies of semi-working sdm lenses and see this same type of improvement. However converting my WORKING sdm lenses has not resulted in a speed increase that I can see. However SDM and Screwdrive do not focus identically - their seeking and settling behavior is a little different so they aren't perfectly comparable. Also in low light failing SDM can be even less decisive so it can really slow down or give up in those situations. My advise is that if SDM is working and you have no "chance of a lifetime" shots coming up on a trip to somewhere that SDM failure would be a problem - keep on using it with SDM. If you have a trip and want to be certain the lenses work the entire time you are gone - convert them! But there are limits of course - noise goes up with conversion, albeit not as bad as some screwdrive lenses. The mass and sealing seem to reduce some of the noise.

In any case, SDM failures seem to be more frequent than other lens failures - but not so common that I would fear them at this point.

[00rob0077]

Here is the status of the four SDM lenses I own:

• 16-50mm f2.8 – converted to screw drive
• 55mm f1.4 – SDM motor failed and replaced in 2020
• 50-135mm f2.8 – intermittent fault where it freezes up
• 300mm f4 – works fine

If the option had been available to convert the 55mm to screw drive I would have done that, however the 55mm (like the 17-70mm) is KAF3 which means it is not possible to focus it with the camera screw drive. The others are KAF2 so can be converted. According to the previous owner (a member of this forum) the 16-50mm focused faster with the screw drive than it did when the SDM motor worked. I love the image quality of these lenses and have taken some great photos with them, but the reliability of the focus units is a problem. I have seen accounts on various forums that the newer batch of motors which replace non-functioning units in recent years have significantly improved reliability. So far my 55mm with a new SDM is working very well.

Is there a way to convert the 16-50mm f2.8 to screw drive using a KP or K1?

[UncleVanya]

Is there a way to convert the 16-50mm f2.8 to screw drive using a KP or K1?

As far as I know the answer is no. It appears the function is there, but the action of attempting to pull/store a copy of the lensrom file fails.

[JVi]

Converting to screwdrive is something I wouldn't mind, but the process is quite beyond my understanding, from what I have read about it.

Converted my SDM 300/4 to screw drive. The process is easy. The hard part is finding a K5 to do it with.

[mikesbike]

If the K-5 can be used, I assume so can the K-5 IIs, and earlier models, like the K20D.

[Nakedgun]

Update: I took advantage of Uncle Vanya's gracious offer to convert SDM to screwdrive operation, and both my afflicted lenses arrived today, now functioning splendidly.

This service, for a trifling fee, is a testament to the wonderful community we are part of.

[UncleVanya]

Update: I took advantage of Uncle Vanya's gracious offer to convert SDM to screwdrive operation, and both my afflicted lenses arrived today, now functioning splendidly.

This service, for a trifling fee, is a testament to the wonderful community we are part of.

I’m glad to be able to continue to offer this service. I try to keep the fees low to encourage people to rejuvenate their lenses. The joy for me is that these lovely lenses get back in regular use.

[UncleVanya]

Converted my SDM 300/4 to screw drive. The process is easy. The hard part is finding a K5 to do it with.

The k100d super, k100d, and k10d all work also. That isn’t a comprehensive list.