[wlachan]

SDM lens is like batteryless torch, if it stops working, CRANK IT!!!

[RobA_Oz]

Doesnt work.
There is a clutch inside the AF mechanisms so if you turn for example the focus ring you don't turn the screw-drive or the SDM motor and it work other way around as well. Would be very bad if you use the SDM that it would turn the motor inside the camera as well.

You will notice that the focus ring is hard to rotate when the AF is active. As I've posted elsewhere here, I manage my DA*16-50 back to health by gently turning the focus ring while depressing the AF button. This is after having taken it apart twice to free up the motor, in the prescribed manner. I am hoping it will eventually correct itself, and at the moment, it seems to be working. I will post if anything adverse happens, so no responsibility taken if it doesn't work for you!

[Anvh]

Rob that might work but your suggestion is different then the one i commented on.

[TheOsOProject]

I had mine repaired once under warranty, then I dropped it about 3 months later from a decent height. 245(US) to fix from CRISCAM.

[PENFRED]

I've had both the 16-50 and the 50-135 for a few years now. If the lenses are not used for a while, the autofocus motor on either "goes to sleep".

I've always been able to wake them up by manually rotating the focus ring a few times and then focusing on something bright; e.g., outside.

Thereafter, autofocus works fine.

worth a shot.

Good luck.

fred

[bossa]

I just got a call from the Australian service centre for Pentax gear that my DA*50-135 was sent back to Japan for repair and that the 'chattery' DA*55 I also gave them is awaiting a new sensor and SDM motor. It was good to speak directly with someone who could say exactly what was going on. I will find out eventually if the motor is an SDM or DC I suppose and I'll let you know all when I have that info.

I may sell off my Pentax gear after this and just concentrate on my Nikon camera if I feel there's just too much risk of failure again.

PS: One reason my DA*50-135 was sent in was due to some decentering that has appeared out of nowhere. Maybe they sent it back to correct that. I don't know if the internals have become misaligned in some way and that this may be affecting the focus mechanism.

[Anvh]

Sensor inside the DA*55?

[bossa]

Sensor inside the DA*55?

I meant to say encoder

[Anvh]

You had me thinking there XD

[lordcyruz]

oh boy ... during the time of reading this thread i´m starting to get worried about if it was worth buying this lens. I got my one march of this year. While using it for several weeks the AF refused "hitting" more often. Now i have to correct AF by internal AF Correction at +10 and at least the lens is hitting again.
Have to bring it to our local Pentax Repair Service in Hamburg, Germany to fix it. I´m really disappointed about the quality of this lens by considering the price (nearly 1000 €)
At least i have still warranty on this lens...

[Anvh]

fast zooms seems problematic for every brand, it's best to go manual focus and without in electronics inside but i doubt anyone would do that.

[EdwardConde]

Should I be worried about ever buying a SDM lens? Specially if they sit for a bit and it starts acting up?

[Anvh]

the DA* primes are no problem at all and the DA*60-250 also looks very decent

[G_Money]

the DA* primes are no problem at all and the DA*60-250 also looks very decent

And yet they're the only two of my DA* lenses that have needed repairs.

[Anvh]

never buy a lottery ticket since the odds seem to be against you