Question for 16-50mm owners

Tom Lusk · 01-15-2008, 03:31 PM

some of these lenses that originally are sharp and exhibit no problems have degraded with use.

Something to do with poor finishing quality in the barrel and parts being ground up/worn out.

I've wanted one of these since they were first introduced, but will not risk the purchase.

How Pentax can produce a great 50-135 but a lemon 16-50 is beyond me.

jbcampbell · 01-15-2008, 05:32 PM

Number 4 was my lucky number... finally a sharp copy of this lens! Below are a few shots from my brief outing today (it was cold here). These are both at 16mm/F2.8 with 100% crops for you pixel peepers ;-)

#1 - 16mm F2.8, focused on the statue.

100% crop of names on statue

#2 - 16mm F2.8 center focus point

100% crop of writing at focus point

This is so much better than the 3 previous copies I had, they were all extremely soft wide open at the wide end of the lens.

Tbear · 01-15-2008, 05:56 PM

Congratulations JB! Good things come to those who wait... and wait.... and wait... and wait

jbcampbell · 01-15-2008, 06:05 PM

Originally posted by Tbear

Congratulations JB! Good things come to those who wait... and wait.... and wait... and wait

I gotta say...I was ready to give up. But the lens came down in price by $150.00 so B&H sent me this replacement & a $150.00 credit on my card. So after all the shipping costs I still came out pretty good. But the main thing is that the lens is great this time around. I am really looking forward to spending a day with this lens.

jgredline · 01-15-2008, 06:27 PM

JB
Those are excellent...I hope my Third copy turns out like your 4th....
I am excited again.

Tbear · 01-18-2008, 07:18 PM

Pentax customer service had my lens from 1/9/08 to 1/18/08. They just shipped the lens back today via UPS. Interestingly, the lens they are sending me back has a different serial number that still begins with 901XXXX. I wonder if my lens was beyond repair and decided to send me a new one or if they sent me someone else's reject. Whether new or used, hopefully the lens they send me works well.

gepe9956 · 01-19-2008, 06:21 AM

Having read all the comments on this thread I was concerned that I may also have a dud copy of the 16 - 50 lens.

I decided to test it myself using a newspaper as the test image.

I set the K10 on a tripod and focused at did tests at the long and short end of the zoom.

First test were at 2.8 and lo and behold the left side of the image was out of focus.

I then stopped down and found it was all IN focus.

I deduced from this that the camera may not be square to to test object.

I then spent quite a bit of time and care setting up the camera back SQUARE to the image plane.

Ran the same test and the images were perfect at 2.8.

My lens id good!

roscot · 01-19-2008, 07:11 AM

The only thing that I have to say about this is, if Pentax expects to be able to compete with Canon and Nikon on a quality level, then there is no excuse for this type of QC problem, ESPECIALLY on a top of the line pro lens.

gawan · 01-19-2008, 11:12 AM

I ordered my DA * 16-50 on July and it arrived to the store just few days ago.

I was almost scared to fetch my lens, because of the many complaints I have read about the quality problems. I had to consider a while at the shop's desk as I saw that the package was a little weary and the lens being an early serial number assembled in Vietnam.

I took it anyway and am now in a get-to-know phase. I like the feel of the lens - nice balance with k10d, ultrasonic focusing is great!

I have not been able to really test it so far, as the weather here is really bad and there is not too much daylight anyway in Helsinki at January.

Instead of great photos (which will come eventually) I did some testing inside (also limited as the only flash I have for now is the build-in one, which is kind a useless with this lens when using the wide end.)

If you are interested, you can see some of my test images at
Picasa Web Albums - gawan

I can't really evaluate the quality until I have the opportunity to shoot in good daylight.
What do you think of the test images (will not call them photographs)?

EDIT: I added now some photos from my first walk around with this lens, they are taken in cloudy weather or in the couple of hours sun light this evening, your evaluation will be very much appreciated.

I have a question for users of SDM lenses: If I manually turn the focus ring it stops at both and positions, sort of, but with just a little more force the ring actually turns past the limits and there is kind of a nasty feel in my fingers, like something is wrong. Is this normal behaviour belonging to SDM or is my focus ring defected?

jbcampbell · 01-19-2008, 11:25 AM

Judging by your test shots at F2.8 I would say got lucky & have a good copy of the lens. My first 3 were unusable wide open.
As for the focus ring, I am not 100% sure with Pentax but with Canon lenses with USM it doesn't hurt to turn it past the stops. But given the nature of these lenses I would make a habit of it ;-)

Enjoy

gawan · 01-19-2008, 11:37 AM

Originally posted by jbcampbell

Judging by your test shots at F2.8 I would say got lucky & have a good copy of the lens. My first 3 were unusable wide open. [...] Enjoy

Thanks for the comment. I think this lens is a little soft at the edges at 16mm wide open, which is also expected, At least I can't see any de-centring.

Forgot to mention that all images are as shot except the focus test which was originally an portrait pic but cropped to landscape to include only the relevant middle part.

Derridale · 01-19-2008, 06:12 PM

Well - I have to say that reading all these problems makes me realize how lucky I am with my lens. Everything seems to be spot on.

Except that here in Australia, even through an online discount retailer, the lens cost me just on $Aus 1200. So you poor sods over the Pacific can stop complaining about your prices...

And yes, I am aware of exchange rates, but we earn our income in Aussie dollars, just as you earn yours in US or Canadian dollars, so a dollar to me is exactly the same as a dollar to you.

But I ain't complaining - at least I don't have the expense, time, and hassle of having to return my lens several times.... yet!

And I also think that the poster above has an excellent point - due to the shallow DOF at wide open f2.8, how many "tests" have been done where the subject (eg newspaper) is EXACTLY square on to the camera, and absolutely flat? Perhaps if the tests were all done with such care, then maybe, just maybe, we wouldn't be seeing quite so many people unhappy....

Tbear · 01-19-2008, 07:06 PM

Originally posted by gepe9956

Having read all the comments on this thread I was concerned that I may also have a dud copy of the 16 - 50 lens.

I decided to test it myself using a newspaper as the test image.

I set the K10 on a tripod and focused at did tests at the long and short end of the zoom.

First test were at 2.8 and lo and behold the left side of the image was out of focus.

I then stopped down and found it was all IN focus.

I deduced from this that the camera may not be square to to test object.

I then spent quite a bit of time and care setting up the camera back SQUARE to the image plane.

Ran the same test and the images were perfect at 2.8.

My lens id good!

That is one of the reasons I compared the * lens with my kit lens. If my sensor was not parallel to the newspaper, I would have seen similar problems with both lenses. The images with the kit lens were fine, proving the DA* lens had the problem.

I'm glad you got a good one, always nice to hear.

Tbear · 01-19-2008, 07:11 PM

Maybe I'm just pixel peeping but look at the print on the philosophy books at f2.8 (there is one in the upper left corner and one in the upper right corner). The words on the cover of the right book look noticeably blurry compared to the left. Again, maybe I'm just imagining things.

Ed in GA · 01-19-2008, 07:19 PM

Originally posted by gawan

I ordered my DA * 16-50 on July and it arrived to the store just few days ago.

I have a question for users of SDM lenses: If I manually turn the focus ring it stops at both and positions, sort of, but with just a little more force the ring actually turns past the limits and there is kind of a nasty feel in my fingers, like something is wrong. Is this normal behaviour belonging to SDM or is my focus ring defected?

If you'll notice when you autofocus with the lens using SDM, the focus ring does not move nor does the head of the lens move in and out.

That fact that you can move the ring beyond the stops is very normal. This concerned me as well when I received mine. I call Pentax Tech support and they explained it to me.

View Poll Results: Is this DA*16-50mm good or bad?
Keep it -- it's good.	23	88.46%
Return it or send it in for repair.	3	11.54%
Voters: 26. You may not vote on this poll

01-15-2008, 03:31 PM	#256
Tom Lusk Veteran Member Join Date: Sep 2006 Photos: Gallery Posts: 973	But... some of these lenses that originally are sharp and exhibit no problems have degraded with use. Something to do with poor finishing quality in the barrel and parts being ground up/worn out. I've wanted one of these since they were first introduced, but will not risk the purchase. How Pentax can produce a great 50-135 but a lemon 16-50 is beyond me.

01-18-2008, 07:18 PM	#261
Tbear Senior Member Join Date: Aug 2007 Location: Pittsburgh, PA Photos: Gallery \| Albums Posts: 269	Update Pentax customer service had my lens from 1/9/08 to 1/18/08. They just shipped the lens back today via UPS. Interestingly, the lens they are sending me back has a different serial number that still begins with 901XXXX. I wonder if my lens was beyond repair and decided to send me a new one or if they sent me someone else's reject. Whether new or used, hopefully the lens they send me works well.

01-19-2008, 06:21 AM	#262
gepe9956 New Member Join Date: Oct 2006 Location: Malta Posts: 4	16 - 50 Newspaper Test Having read all the comments on this thread I was concerned that I may also have a dud copy of the 16 - 50 lens. I decided to test it myself using a newspaper as the test image. I set the K10 on a tripod and focused at did tests at the long and short end of the zoom. First test were at 2.8 and lo and behold the left side of the image was out of focus. I then stopped down and found it was all IN focus. I deduced from this that the camera may not be square to to test object. I then spent quite a bit of time and care setting up the camera back SQUARE to the image plane. Ran the same test and the images were perfect at 2.8. My lens id good!

01-19-2008, 11:12 AM	#264
gawan Veteran Member Join Date: Jul 2007 Location: Helsinki Photos: Gallery Posts: 5,400	*My new DA 16-50mm f/2.8** I ordered my DA * 16-50 on July and it arrived to the store just few days ago. I was almost scared to fetch my lens, because of the many complaints I have read about the quality problems. I had to consider a while at the shop's desk as I saw that the package was a little weary and the lens being an early serial number assembled in Vietnam. I took it anyway and am now in a get-to-know phase. I like the feel of the lens - nice balance with k10d, ultrasonic focusing is great! I have not been able to really test it so far, as the weather here is really bad and there is not too much daylight anyway in Helsinki at January. Instead of great photos (which will come eventually) I did some testing inside (also limited as the only flash I have for now is the build-in one, which is kind a useless with this lens when using the wide end.) If you are interested, you can see some of my test images at Picasa Web Albums - gawan I can't really evaluate the quality until I have the opportunity to shoot in good daylight. What do you think of the test images (will not call them photographs)? EDIT: I added now some photos from my first walk around with this lens, they are taken in cloudy weather or in the couple of hours sun light this evening, your evaluation will be very much appreciated. I have a question for users of SDM lenses: If I manually turn the focus ring it stops at both and positions, sort of, but with just a little more force the ring actually turns past the limits and there is kind of a nasty feel in my fingers, like something is wrong. Is this normal behaviour belonging to SDM or is my focus ring defected? Last edited by gawan; 01-20-2008 at 01:02 PM. Reason: correcting typos

01-15-2008, 05:32 PM	#257
jbcampbell Senior Member Join Date: Aug 2007 Location: Lynchburg, VA Posts: 215	Number 4 was my lucky number... finally a sharp copy of this lens! Below are a few shots from my brief outing today (it was cold here). These are both at 16mm/F2.8 with 100% crops for you pixel peepers ;-) #1 - 16mm F2.8, focused on the statue. 100% crop of names on statue #2 - 16mm F2.8 center focus point 100% crop of writing at focus point This is so much better than the 3 previous copies I had, they were all extremely soft wide open at the wide end of the lens.

01-15-2008, 05:56 PM	#258
Tbear Senior Member Join Date: Aug 2007 Location: Pittsburgh, PA Photos: Gallery \| Albums Posts: 269	Congratulations JB! Good things come to those who wait... and wait.... and wait... and wait

01-15-2008, 06:05 PM	#259
jbcampbell Senior Member Join Date: Aug 2007 Location: Lynchburg, VA Posts: 215	Originally posted by Tbear Congratulations JB! Good things come to those who wait... and wait.... and wait... and wait I gotta say...I was ready to give up. But the lens came down in price by $150.00 so B&H sent me this replacement & a $150.00 credit on my card. So after all the shipping costs I still came out pretty good. But the main thing is that the lens is great this time around. I am really looking forward to spending a day with this lens.

01-15-2008, 06:27 PM	#260
jgredline Veteran Member Join Date: Oct 2007 Location: LosAngeles, Ca. Photos: Albums Posts: 10,628	JB Those are excellent...I hope my Third copy turns out like your 4th.... I am excited again.

01-19-2008, 07:11 AM	#263
roscot Veteran Member Join Date: Sep 2006 Location: Virginia Beach VA USA Photos: Gallery Posts: 1,363	The only thing that I have to say about this is, if Pentax expects to be able to compete with Canon and Nikon on a quality level, then there is no excuse for this type of QC problem, ESPECIALLY on a top of the line pro lens.

01-19-2008, 11:25 AM	#265
jbcampbell Senior Member Join Date: Aug 2007 Location: Lynchburg, VA Posts: 215	Judging by your test shots at F2.8 I would say got lucky & have a good copy of the lens. My first 3 were unusable wide open. As for the focus ring, I am not 100% sure with Pentax but with Canon lenses with USM it doesn't hurt to turn it past the stops. But given the nature of these lenses I would make a habit of it ;-) Enjoy

01-19-2008, 11:37 AM	#266
gawan Veteran Member Join Date: Jul 2007 Location: Helsinki Photos: Gallery Posts: 5,400	Originally posted by jbcampbell Judging by your test shots at F2.8 I would say got lucky & have a good copy of the lens. My first 3 were unusable wide open. [...] Enjoy Thanks for the comment. I think this lens is a little soft at the edges at 16mm wide open, which is also expected, At least I can't see any de-centring. Forgot to mention that all images are as shot except the focus test which was originally an portrait pic but cropped to landscape to include only the relevant middle part. Last edited by gawan; 01-19-2008 at 03:58 PM.

01-19-2008, 06:12 PM	#267
Derridale Veteran Member Join Date: Jan 2008 Location: Brisbane, Australia Posts: 412	Well - I have to say that reading all these problems makes me realize how lucky I am with my lens. Everything seems to be spot on. Except that here in Australia, even through an online discount retailer, the lens cost me just on $Aus 1200. So you poor sods over the Pacific can stop complaining about your prices... And yes, I am aware of exchange rates, but we earn our income in Aussie dollars, just as you earn yours in US or Canadian dollars, so a dollar to me is exactly the same as a dollar to you. But I ain't complaining - at least I don't have the expense, time, and hassle of having to return my lens several times.... yet! And I also think that the poster above has an excellent point - due to the shallow DOF at wide open f2.8, how many "tests" have been done where the subject (eg newspaper) is EXACTLY square on to the camera, and absolutely flat? Perhaps if the tests were all done with such care, then maybe, just maybe, we wouldn't be seeing quite so many people unhappy....

01-19-2008, 07:06 PM	#268
Tbear Senior Member Join Date: Aug 2007 Location: Pittsburgh, PA Photos: Gallery \| Albums Posts: 269	Originally posted by gepe9956 Having read all the comments on this thread I was concerned that I may also have a dud copy of the 16 - 50 lens. I decided to test it myself using a newspaper as the test image. I set the K10 on a tripod and focused at did tests at the long and short end of the zoom. First test were at 2.8 and lo and behold the left side of the image was out of focus. I then stopped down and found it was all IN focus. I deduced from this that the camera may not be square to to test object. I then spent quite a bit of time and care setting up the camera back SQUARE to the image plane. Ran the same test and the images were perfect at 2.8. My lens id good! That is one of the reasons I compared the * lens with my kit lens. If my sensor was not parallel to the newspaper, I would have seen similar problems with both lenses. The images with the kit lens were fine, proving the DA* lens had the problem. I'm glad you got a good one, always nice to hear.

01-19-2008, 07:11 PM	#269
Tbear Senior Member Join Date: Aug 2007 Location: Pittsburgh, PA Photos: Gallery \| Albums Posts: 269	Maybe I'm just pixel peeping but look at the print on the philosophy books at f2.8 (there is one in the upper left corner and one in the upper right corner). The words on the cover of the right book look noticeably blurry compared to the left. Again, maybe I'm just imagining things.

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01-19-2008, 07:19 PM	#270
Ed in GA Guest	Originally posted by gawan I ordered my DA * 16-50 on July and it arrived to the store just few days ago. I have a question for users of SDM lenses: If I manually turn the focus ring it stops at both and positions, sort of, but with just a little more force the ring actually turns past the limits and there is kind of a nasty feel in my fingers, like something is wrong. Is this normal behaviour belonging to SDM or is my focus ring defected? If you'll notice when you autofocus with the lens using SDM, the focus ring does not move nor does the head of the lens move in and out. That fact that you can move the ring beyond the stops is very normal. This concerned me as well when I received mine. I call Pentax Tech support and they explained it to me.