[TysonG]

Hey Peter!

As for what's been reported here an on DPReview, there doesn't seem to be a consistent pattern. At the least, we haven't seen enough series of close SNs to see what might constitute a 'batch' or given production run. So we don't know if QC is variable on a copy-by-copy or batch-by-batch basis. To make matters even murkier, it doesn't appear that it's an all-good or all-bad type of defect: some have exhibited severe decentering, while others have no decentering but a far softer than they should be even stopped down.

I'm even starting to wonder about my own copy, which initially seemed good. In some focus chart tests, I noticed that the left side seemed smearier than the right. This smacks of the classic decentering issue, but I can't be sure as I could not control either the levelness of the focus chart (floor is tilted) nor the camera (pistol-grip ball head with no home-level position). So it could've just been a plane-of-focus issue. So far in real world shots it's great and have already used it satisfactorily in a paid job, so I'm not worrying about it.

[axl]

thanks Tyson.
I just wanted to find out because I've seen used copy here in London for good price. I gave it a go, and it seemed OK though of course I didn't really do any propper tests.
I will see...
thanks anyway

Peter

[PolishMike]

Oh, oh! I got one! It was terrible - top right corner like a sonar image, overall sharpness leagues worse than my 1st gen kit lens at matched apertures (all this on a tripod, remote release, mirror lockup , SR off).
Serial number: 9028644

I had it sent back to SRS Microsystems, who sent it to the Pentax service centre somewhere, who couldn't fix it so sent it to Japan. This was a month ago. Just called them - apparently the lens is yet to be fixed. It will the be shipped from Japan to Pentax HQ in Germany, who will ship it to Pentax UK, who will ship it to the repair company which SRS use, who will send it back to SRS, from where it may or may not be finally sent to me.
I wish I could go travelling as much as my lenses do!

EDIT: 2 months now and still no lens. Asked SRS if they could just send me a replacement, but they refused saying that the new batches of lenses cost them so much more to buy in that they cannot give me a "new price" lens when I only bought an "old price" one. And here I was thinking a DA* is a DA*.

MORE EDIT: WAs supposed to be with me at the beginning of the month. No word from SRS still.

[walay]

This is my 2nd replacement of this this lens with SN# 9013566.
I have a question, because maybe my expectation is too high as I had some smooth zooming and focusing manual and other lenses. But for the 16~50mm. When rotating the zoom, is it suppose to be really smooth or no? To me the past 2lenses including this one always seems tight to zoom, and not smooth as there seems to be a damping point when going to 28mm.
for example, I turn the zoom from 16~25mm easily and as it get to 28mm, it becomes tighter and I have to turn harder to get pass it and to 50mm, but when I zoom back from 50mm to 16mm, its smooth with constant force applied. Also, for manual focus, when I turn the focus ring, it sounded like there is metal balls rolling against something. I posted a video here for everyone to see. Is this something I need to be concerned about, please let me know if I need to send it back again. I haven't tested the lens yet, because I'm at work and don't have camera with me, and the lens shipped to my work today.

Here is link to video: YouTube - MVI 4437

[nostatic]

This is my 2nd replacement of this this lens with SN# 9013566.
I have a question, because maybe my expectation is too high as I had some smooth zooming and focusing manual and other lenses. But for the 16~50mm. When rotating the zoom, is it suppose to be really smooth or no? To me the past 2lenses including this one always seems tight to zoom, and not smooth as there seems to be a damping point when going to 28mm.
for example, I turn the zoom from 16~25mm easily and as it get to 28mm, it becomes tighter and I have to turn harder to get pass it and to 50mm, but when I zoom back from 50mm to 16mm, its smooth with constant force applied. Also, for manual focus, when I turn the focus ring, it sounded like there is metal balls rolling against something. I posted a video here for everyone to see. Is this something I need to be concerned about, please let me know if I need to send it back again. I haven't tested the lens yet, because I'm at work and don't have camera with me, and the lens shipped to my work today.

Here is link to video: YouTube - MVI 4437

I think they all feel that way - has to do with the way the tubes move and the weather sealing. It is a little "one way" with the friction.

[Pål Jensen]

This is my 2nd replacement of this this lens with SN# 9013566.
I have a question, because maybe my expectation is too high as I had some smooth zooming and focusing manual and other lenses. But for the 16~50mm. When rotating the zoom, is it suppose to be really smooth or no? To me the past 2lenses including this one always seems tight to zoom, and not smooth as there seems to be a damping point when going to 28mm.
for example, I turn the zoom from 16~25mm easily and as it get to 28mm, it becomes tighter and I have to turn harder to get pass it and to 50mm, but when I zoom back from 50mm to 16mm, its smooth with constant force applied. Also, for manual focus, when I turn the focus ring, it sounded like there is metal balls rolling against something. I posted a video here for everyone to see. Is this something I need to be concerned about, please let me know if I need to send it back again. I haven't tested the lens yet, because I'm at work and don't have camera with me, and the lens shipped to my work today.

Here is link to video: YouTube - MVI 4437

It is normal for this lens....

[opiedog]

i'm also looking to purchase this lens over the tamron 17-50 or sigma 18-50.
but i'm still leery from all the reported QC issues.

has the number of QC issues decreased in 2009 or is it just that less people are buying this lens and hence, less reports?

tnx

jordan

[uwmechengr]

I'm going to say S/N #9022552 is good. See my first samples to help me if I'm right or not. I'm satisfied with it, atleast.

[nostatic]

Anyone ever seen a case where the lens consistently underexposes at 16mm but is fine at 50mm (shooting P mode)? I tried one recently and that was the case. And we're not talking like -0.3ev - 16mm was a lot darker. Exact same subject, lighting, etc. Another copy was just fine.

[inferno10]

Just got a replacement DA* 16-50 from the Pentax Colorado repair facility. SN 9013759 still front-focuses on my K-7. Even worse, the focus ring does not operate smoothly. The SDM isn't strong enough to move the focus element, so AF can't function. Needless to say, it's going right back to the repair facility. I'll even send them my K-7 which has been having the issues with the lens. I'm pretty frustrated at the moment...

- Jason

[mtngal]

Just got 4 different lenses, one of which was the 16-50. SN is 9028197 and it's going back to B&H for exchange - definite decentering (left side much blurrier than right when taking pictures of a brick wall straight on). It's also blurry at all apertures, my 1st gen. kit lens is better. Granted, I was hand-holding but the 300mm lens I was also testing was tack-sharp, at similar shutter speeds, so I don't think I'd see anything different if I had used a tripod.

[Urkeldaedalus]

9028043 here and looking good to me.

[mtngal]

I'm reluctantly (very reluctantly) going to send back my replacement lens s/n 9023172. It's center sharpness is excellent, focus is perfect, but the right side is significantly blurred (left side is blurred too, just not as much). I just took a look at some comparison shots between the DA 12-24 and this lens (should have done that yesterday). While the 12-24 is not as sharp in the center, there's no significant edge blurriness, not like this 16-50 has.

Second guessing things - I wonder if this lens left the factory as a perfectly good lens (the center is so sharp you can cut yourself on it) but was damaged in shipment. The box it arrived in looked like it had been thrown or dropped on one end - the sides all around one end were crinkled. It was well packed and the inner box was perfect, but I'm wondering if it had been manhandled hard enough to crumple the box, if that would have been enough to jar something out of alignment. Also, the zoom ring seemed stiffer than the other one (and stiffer than I had expected). It makes me question the wisdom of buying strictly through mail-order.

[Pentax_XTC]

9023201 is good.
Got it from Adorama yesterday, and I'm loving it! I'm glad I took the chance on ordering it.

[jmpentax]

SN 9024992.

Good copy.

Purchased by eBay, seller DCTrade, location Hong Kong.

I don´t remember the date exactly, but could be during end of December 2008 and begining January 2009.