[aslyfox]

I am trying out a " experienced " SMC Pentax DA* 60-250mm

what can be done if the SDM fails ?

how can the lens be converted to screw drive

Like all current DA lenses, the SMC Pentax DA* 60-250mm is designed only for Pentax DSLR cameras. It was announced in late February, 2007. It auto-focuses with an SDM ultrasonic motor on the K10D (firmware 1.30) and newer cameras. On older cameras the lens will auto-focus with the 'screw drive' mechanism.

Read more at: SMC Pentax-DA* 60-250mm F4 ED [IF] SDM Reviews - DA Zoom Lenses - Pentax Lens Reviews & Lens Database

[pearsaab]

it can't be converted unless something has changed

[aslyfox]

can a sdm drive be repaired/replaced ???

[brianmquinn]

Yes, I think Precision Camera and Video is the place to send it. That is who worked on my K-5 and fixed it perfectly.

[AstroDave]

There's alway manual focus!! As, in the olden days (when some of us grew up).

Not good for for BiF (birds in flight) but fine for landscapes - especially in live view.

[aslyfox]

There's alway manual focus!! As, in the olden days (when some of us grew up).

Not good for for BiF (birds in flight) but fine for landscapes - especially in live view.

Not good for fast moving wildlife either

[UncleVanya]

No you cannot convert that lens. It’s the only ones off the dial focusing system lenses that can’t be converted.

There was one report but I’m still unclear if that was a false flag event or if they had a unicorn.

[krazny]

I suppose I have the Unicorn copy in question.

I did manage to revive the sdm by doing the firmware hack.

Conversion to screwdrive seems to have fixed SDM (?) - PentaxForums.com

It is still alive and kicking more than 6 months later.

[UncleVanya]

I suppose I have the Unicorn copy in question.

I did manage to revive the sdm by doing the firmware hack.

Conversion to screwdrive seems to have fixed SDM (?) - PentaxForums.com

It is still alive and kicking more than 6 months later.

Actually no, you aren’t in possession of the unicorn. Yours seems to be in line with existing known results - except you have the rate lens that was stuck and just needed to be exercised to get sdm working again. At least that’s my assessment. The unicorn was a lens that was converted in Russia. The lens was supposedly screwdrive only post conversion. The lens files were normal and had zero differences from other attempts at converting other lenses. The op claimed the people that converted it made a hardware change also and they wouldn’t share the method to preserve their ability to sell conversions. But they also never offered conversions here. It was peculiar. If I recall the user recanted their claim somewhat later. It may have been a fluke that stopped working I don’t recall.

Your results however suggest that in some cases it might be worth trying to reawaken dead sdm in some lenses. Interesting food for thought.

---------- Post added 02-12-22 at 08:11 AM ----------

I’ll make an offer in this thread. If anyone has a dead sdm 60-250 they want to try using this method on to revive it - contact me. I offer conversion services and my normal process is to refund the conversion fee if the conversion isn’t successful. I have not up to now allowed users to send me the 60-250 since I wasn’t able to reliably convert my own copy (with working sdm).

I am willing to take on a few copies and see if we can recreate your unicorn results.

[krazny]

Actually no, you aren’t in possession of the unicorn. [...]

Ahh an actual Unicorn

But am I wrong thinking that the lens files from the 16-50/50-135 are different to the lens file from the 60-250 ?

I can't seem to find a file from either of the two lenses but if I remember correctly the 60-250 file had more lines than the other files.

Am I mistaken?

[UncleVanya]

Ahh an actual Unicorn

But am I wrong thinking that the lens files from the 16-50/50-135 are different to the lens file from the 60-250 ?

I can't seem to find a file from either of the two lenses but if I remember correctly the 60-250 file had more lines than the other files.

Am I mistaken?

I would have to look. All the files are specific not oly to the model but also the specific lens. The structure does vary mostly zoom vs prime. But I think you are right.

[Wheatfield]

Not good for fast moving wildlife either

The last thing the DA60-250 is good for is fast moving wildlife. Even if the SDM is working properly, a snail will probably outpace the focus speed of the lens.
The optics are decent, the SDM can be repaired, and probably will need to be multiple times over the life of the lens.
My advise, FWIW, is buy it with the intent of using it as a manual focus lens and be pleasantly surprised that the AF works, albeit slowly, until it doesn't.

[gatorguy]

Actually no, you aren’t in possession of the unicorn. Yours seems to be in line with existing known results - except you have the rate lens that was stuck and just needed to be exercised to get sdm working again. At least that’s my assessment. The unicorn was a lens that was converted in Russia. The lens was supposedly screwdrive only post conversion. The lens files were normal and had zero differences from other attempts at converting other lenses. The op claimed the people that converted it made a hardware change also and they wouldn’t share the method to preserve their ability to sell conversions. But they also never offered conversions here. It was peculiar. If I recall the user recanted their claim somewhat later. It may have been a fluke that stopped working I don’t recall.

Your results however suggest that in some cases it might be worth trying to reawaken dead sdm in some lenses. Interesting food for thought.[COLOR="Silver"]

I'll mention that I was able to revive the dead SDM in my *55 by mounting it on the K3III.

[aslyfox]

The last thing the DA60-250 is good for is fast moving wildlife. . . .

I yield to someone with more experience

[Wheatfield]

I yield to someone with more experience

At best its AF is still slow. They took great optics and paired them with a really sub par auto focus.