[offertonhatter]

Has anyone had a problem with this lens?

I was doing to publicity shoots on Thursday and put this lens on the K20D.
Problems I was having was that the lens would not focus at all, whether in AF or MF.
After taking the lens off and on the camera many times, I would focus, but the images were black even with my 540fgz providing light.
I changed lenses (fortunately having another lens with me, namely my Sigma 24-70mm F2.8)
I did the shoot with the sigma, and after the shoot, I put the DA* back on. This time it worked fine.
This is the first time this has happened, so a little worried that it could happen again.

Advices please

[nostatic]

the only issue I've read here is possible dirty contacts. Maybe clean them with some alcohol on a lint-free cloth.

[offertonhatter]

That could explain some, but not able to focus in MF? I will give the contacts a clean anyway. so thanks for that

If it's still in warranty, use it as much as you can to try and recreate the problem.

[hinckc]

Hi offertonhatter,

I've been having similar but slightly different issues with my 50-135 recently...

When I tried to auto-focus via AF button, the lens seemed to try to go in both directions, and quickly gave up. The difference was that my lens was manually focusing OK, though it felt slightly less smooth as it turned, compared to normal.

I tried re-mounting, still no AF. I tried wiping the contacts, still no AF.
Then I tried shaking it a bit (not hard), but enough to see if I could tell if something had broken loose inside. It seemed normal, nothing loose. But after that, auto-focus worked again.

This has happened to me 2 times now, so I think I'm sending mine back to be checked out.
Now I'm finally glad I haven't sold my 'backup' Tamron 18-250 to fund a DA21...

-Chris

[christinelandon]

I've experienced no problems whatever with mine, if you don't count it being just a bit "short" on the long end of its range...I hope yours doesn't develop its recent glitch into a bad habit!

FWIW, I'd follow the recommendations above to clean the contacts (both the lens and the body contacts, too). Maybe a few times, just to be sure. I'd use a cotton swab lightly (very lightly!) sprayed with a good electrical contact cleaner.

[NeverSatisfied]

Offerton, Hinck, if your lenses are still under warranty better send them in now. At worst it'll cost you about $15 in shipping, at best you might save a couple hundred by not waiting until the warranty expired, like I did.

There -have- been similar problems reported with the SDM/AF on the DA*50-135. I'm sure it's a small percentage overall but still no comfort to those who do experience it.

On a happier note, I called Pentax back and they reduced my labor charges (my warranty expired about two months before I sent it in), and it will now only cost me about $160 to get it fixed...

QC issues aside, with the DA* lenses considered the top of the line, and quite a bit costlier, you'd think the warranty period would be a little more substantial. If Tamron can offer a six-year warranty, you'd think Pentax could at least offer more than just one year.

[riotsquad]

Hi, a while ago, shortly after Christmas my 50-135 would not auto focus, but manual focus was fine. I tried taking the lens off a couple of times and that didn't work. I got out a q-tip and some alcohol and cleaned the contacts on both the camera and the lens and it has worked fine ever since.
Paul

[NeverSatisfied]

Every time some one has trouble with the AF / SDM on the DA*50-135, they always end up receiving tips on how to clean the contacts! I don't know about anyone else but it's not like I go rolling around in the mud with my camera or anything, I take very good care of my equipment and always keep it clean and free of dust, etc. One -should- clean the contacts if experiencing trouble. Geez, why do so many people have dirty contacts with this lens?

So OK, I "cleaned the contacts", it didn't work, and I sent the lens in to Pentax. I doubt they'd charge $250 parts and labor (like I said, they knocked that down a bit- thanks Dorian!), just to apply alcohol to the contacts!

Nobody knows what percentage of DA*50-135 lenses are having these problems, except Pentax. I'm sure the percentage is low. But the fact remains, -some- people are having trouble with it, and so, once you've "cleaned the contacts", if it gives you any more trouble, you'd better have it checked out before the warranty expires.

That being said, it IS a superb lens in all other regards. (And hey, nobody says you can't still manual focus with it! Or even use "Catch-In Focus".) The image quality is excellent and I have a very high percentage of "keepers" with it. I can't wait to get mine back.

[Timtast1c]

im having the same problems....sigh

[Torphoto]

I vote for dirty contacts, I had a similar problem and once I cleaned the contacts on both the lens and camera it was fine again.

[Timtast1c]

took this fussy one and and guess what..

Ahh now here are some photos of the DA* 50-135 doing exactly what I want!

[legacyb4]

Wow, beautiful shots. I guess it's warm enough down south that the cherry blossoms are already out!

took this fussy one and and guess what..

Ahh now here are some photos of the DA* 50-135 doing exactly what I want!

[xjjohnno]

You're obviosly the victim of a recalitrant lens. Out of the goodness of my heart I will offer you my lens rehabilitation services and not charge you either rehabillitation or transpotation fees.

[Rupert]

I would be very watchful of the condition described by the OP. My DA*50-135 was exhibiting very similar problems before it just went completely dead as far as AF. The SDM completely failed. I sent it in for warranty service on 1-29-09 and hope to be seeing it back soon. There has been quite a few similar reports, although I don't know what % it is, it appears to be a little too common for comfort. The lens still worked fine on my DS using the screw drive, and there have been requests to Pentax to allow the K20D to use screw drive with SDM lenses if the SDM fails. No response so far, that I am aware of. Maybe we will hear something soon?
As for IQ, the 50-135 is a spectacular lens, and rivals primes from most reports I have read. It has certainly been one of my favorite lenses, and whatever is necessary to keep it in use, I hope Pentax will provide.