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View Poll Results: Is this DA*16-50mm good or bad?
Keep it -- it's good. 2388.46%
Return it or send it in for repair. 311.54%
Voters: 26. You may not vote on this poll

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01-04-2008, 06:21 AM   #211
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Rico,

I actually took many more images at different focal lengths and apertures with both the kit and the * lens with the tripod, camera and newspaper in the EXACT SAME position. Every single image showed the same thing: the kit lens demonstrated good, equal sharpness on the left, center and right aspects; the * lens showed poor sharpness on the left on every single image! If that isn't proof that there is a problem with my * lens, then I don't know what is.

01-04-2008, 06:41 AM   #212
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QuoteOriginally posted by Tom Lusk Quote
"They told me they were unaware of any QC issues with this lens or with their Vietnam factory"

What complete cr*p!

From all the posts I've read about this particular lens, they must have had a record number of these lenses returned to them.

They should refund your shipping charges, give you a new lens - and an apology.

Be thankful you don't have to deal with Pentax Canada - still waiting for an answer to my email from a month ago.
Agreed. I've had no luck with them and emails as well. I've dealt with Pentax USA which was quick and easy. They've answered questions and on 2 occasions, I've had product breakdown line drawings faxed to me from them.

My experience with buying a DA*16-50 was the same. I returned it to the online retailer for a full refund and he was good about it. Pentax has to know. There have been too many returns. I'd never consider getting this lens used, now or years from now without hands on testing.
01-04-2008, 06:43 AM   #213
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QuoteOriginally posted by Tbear Quote
Rico,

I actually took many more images at different focal lengths and apertures with both the kit and the * lens with the tripod, camera and newspaper in the EXACT SAME position. Every single image showed the same thing: the kit lens demonstrated good, equal sharpness on the left, center and right aspects; the * lens showed poor sharpness on the left on every single image! If that isn't proof that there is a problem with my * lens, then I don't know what is.
Wow that must be really bad then. I love the center resolution on the kit but its fairly dismal in the corners...somehow mashes the finer details into blobs of colour particularly at the wider end. Perhaps its time for our insiders to voice the concerns to their contacts directly if they haven't already...
01-04-2008, 10:11 AM   #214
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Tbear if the camera was not square from the start you could shoot at a thousand different focal lengths and get the same results. Did you repeat the test by umounting the camera and remounting it. Which lens did you shoot with first?

01-04-2008, 02:23 PM   #215
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QuoteOriginally posted by Rico Quote
Tbear if the camera was not square from the start you could shoot at a thousand different focal lengths and get the same results. Did you repeat the test by umounting the camera and remounting it. Which lens did you shoot with first?
Hi Rico,

Yeah, I did my test using a number of different focal length, aperture combinations such as 18mm f/3.5, 31mm f/4, etc. I can tell you with absolute certainty that the newspaper position and camera position were identical for all test shots. The camera was very rigidly fixed to a heavy duty tripod during the single lens change that was performed. The results all basically showed the same thing over and over again: namely, that the kit lens showed no discernible difference in sharpness between left and right sides of the image, while the * lens showed poor sharpness on the left with no problem with sharpness on the right. I think it is difficult to draw a conclusion other than the obvious one: my copy of the DA* 16-50 has a serious lens alignment problem.
01-04-2008, 02:24 PM   #216
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QuoteOriginally posted by Rico Quote
Tbear if the camera was not square from the start you could shoot at a thousand different focal lengths and get the same results. Did you repeat the test by umounting the camera and remounting it. Which lens did you shoot with first?
Hi Rico,

Yeah, I did my test using a number of different focal length, aperture combinations such as 18mm f/3.5, 31mm f/4, etc. I can tell you with absolute certainty that the newspaper position and camera position were identical for all test shots. The camera was very rigidly fixed to a heavy duty tripod during the single lens change that was performed. The results all basically showed the same thing over and over again: namely, that the kit lens showed no discernible difference in sharpness between left and right sides of the image, while the * lens showed poor sharpness on the left with no problem with sharpness on the right. I think it is difficult to draw a conclusion other than the obvious one: my copy of the DA* 16-50 has a serious lens alignment problem. If it makes a difference to you, I shot with the * lens first and then the kit lens.
01-04-2008, 02:29 PM   #217
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QuoteOriginally posted by Rico Quote
Tbear if the camera was not square from the start you could shoot at a thousand different focal lengths and get the same results. Did you repeat the test by umounting the camera and remounting it. Which lens did you shoot with first?
Hi Rico,

Yeah, I did my test using a number of different focal length, aperture combinations such as 18mm f/3.5, 31mm f/4, etc. I can tell you with absolute certainty that the newspaper position and camera position were identical for all test shots. The camera was very rigidly fixed to a heavy duty tripod during the single lens change that was performed. The results all basically showed the same thing over and over again: namely, that the kit lens showed no discernible difference in sharpness between left and right sides of the image, while the * lens showed poor sharpness on the left with no problem with sharpness on the right. I think it is difficult to draw a conclusion other than the obvious one: my copy of the DA* 16-50 has a serious lens alignment problem. I never removed the camera from the tripod during the entire test. The single lens change was very very carefully done so as not to disturb the camera/tripod position in any way. This was not difficult to accomplish as I made sure the tripod was gripping my camera like a vice.
01-04-2008, 02:59 PM   #218
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Well so far I have returned two copies of the lens and the third should be in next week. Hopefully it will be fixed. My 50-135* is amazing...

I had also not thought of a newspaper test, but will have to do that. Great job and I share in your frustration. If I were a pro, I would be angry and upset, instead of just upset.

01-04-2008, 03:15 PM   #219
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QuoteOriginally posted by SupremeMoFo Quote
Um, and you've never tried again? Any more than 2 business days and I'd be re-sending or hassling by phone!!
I probably should have, but I got the info I needed elsewhere. Hence, I didn't bother trying for a second ignored inquiry.
01-04-2008, 04:19 PM   #220
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Tbear all I was asking is if you did more than one test. The results you got for one test are all the same which would make sense. In no way do I see one test as conclusive to any thing other than for that one test the lens focused consistently the same. Your conclusion can be that there is something wrong with the lens but it does not rule out that there was not something wrong with your test. As you only did one test.

Sending the lens back to whom you purchased it from would have been a much quicker turn around if you were still in the range of the retailers exchange policy. IMHO.
01-04-2008, 04:38 PM   #221
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QuoteOriginally posted by Rico Quote
Tbear all I was asking is if you did more than one test. The results you got for one test are all the same which would make sense. In no way do I see one test as conclusive to any thing other than for that one test the lens focused consistently the same. Your conclusion can be that there is something wrong with the lens but it does not rule out that there was not something wrong with your test. As you only did one test.



Sending the lens back to whom you purchased it from would have been a much quicker turn around if you were still in the range of the retailers exchange policy. IMHO.
We can agree to disagree on the validity of my test findings.

No question, you are right that turn around time would be faster sending it back to the retailer. However, I purposely sent it to Pentax, in part because they told me that they were not aware of any problems with this lens, which is rather humorous (or sad depending on your perspective). I wanted Pentax to test this lens for themselves and see if they think it falls within their specifications. I don't mind waiting a little longer for Pentax's response.
01-04-2008, 04:40 PM   #222
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QuoteOriginally posted by Tbear Quote
No question, you are right on this one. However, I purposely sent it to Pentax, in part because they told me that they were not aware of any problems with this lens, which is rather humorous (or sad depending on your perspective). I wanted Pentax to test this lens for themselves and see if they think it falls within their specifications.
I hit it lucky, I guess. My 16-50 shows no flaws other than the CAs, and I think only a redesign will solve that problem.
01-04-2008, 04:43 PM   #223
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QuoteOriginally posted by Canada_Rockies Quote
I hit it lucky, I guess. My 16-50 shows no flaws other than the CAs, and I think only a redesign will solve that problem.
I would have had a party if my 16-50 was like yours.
01-04-2008, 04:47 PM   #224
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QuoteOriginally posted by Tbear Quote
I would have had a party if my 16-50 was like yours.
You can actually see a bottom left corner shot from the 16-50 on my flickr shots. I don't think I have anything to complain about. It's not a newspaper test, but I don't see any OOF problems with it. Check the printing on the police tape.

Crop from bottom left corner of Fire on Flickr - Photo Sharing!
01-04-2008, 04:54 PM   #225
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QuoteOriginally posted by Canada_Rockies Quote
You can actually see a bottom left corner shot from the 16-50 on my flickr shots. I don't think I have anything to complain about. It's not a newspaper test, but I don't see any OOF problems with it. Check the printing on the police tape.

Crop from bottom left corner of Fire on Flickr - Photo Sharing!
I have never doubted that there are well-made copies of the DA* 16-50mm out there. I'm hoping that the lens Pentax sends back to me will be among them.
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