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View Poll Results: Good Lens or Bad Lens
Bad Lens - Lens have problem...replace it again 125.00%
Bad Lens - User have problem...replace the user 375.00%
Voters: 4. You may not vote on this poll

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05-10-2010, 01:04 PM   #1
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Do I have a bad DA* 16-15mm Lens? Please help me determine

(Poll Correction: the 2nd choice should be "Good Lens" not "Bad Lens")

Hi, This is my 2nd replacement of the DA" 16-50mm.
Original was decentered, 1st replacement had scratches, and here is the 2nd.

My problem is, no matter what the settings are, the images I took just dosen't look sharp and too soft. What I want to know is, is this how this lens supposed to be, or do I have too high of expectation. The only other lens I have to compare are DA*50-135/A* 135mm/DA Macro 100mm which all took extremely sharp photos, so I just need to know if I had too much expection for the 16-50mm....or do I need another replacement again..... I have linked here to various photos I took with the lens under different condition and settings.

Photos here from the lens at my album PentaxForums.com - walay's Albums

Attached a new comparison jpeg and its photoshop file.

So please help me and let me know if its the lens or...me...?

Attached Images
 
Attached Images
File Type: psd photoshop file.psd (1.01 MB, 191 views)

Last edited by walay; 05-12-2010 at 06:43 PM. Reason: poll/typo
05-10-2010, 01:17 PM   #2
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I would vote if you had a third option:

"Bad Lens. What was I thinking? I was warned. Buy a different lens."

Does my contempt for this lens show much?

Last edited by PentaxPoke; 05-10-2010 at 01:34 PM.
05-10-2010, 01:25 PM   #3
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I don't have this lens yet (and probably won't after seeing so many complaints about it) but based on other pics I've seen from this forum and flickr, I would be about 90% certain that you have another suspect copy and you would need to go through the hassle of getting another replacement.....
05-10-2010, 01:37 PM   #4
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First of all, the 16-50/2.8 produces very sharp images with good contrast and is very useable, even fully open. That is at least the case, if you got a good copy.

Whether you got a lame duck again, I canot say. I must say, that the example images are too smal, web-compressed and some of them generally not really telling much about lens quality, as other factors could have influenced the image quality more, than lens properties.

Ben

05-10-2010, 01:46 PM   #5
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QuoteOriginally posted by Ben_Edict Quote
First of all, the 16-50/2.8 produces very sharp images with good contrast and is very useable, even fully open. That is at least the case, if you got a good copy.
Ben,

I'm sorry but I disagree with you on one point. Assuming one gets a good copy of the DA* 16-50, only the center resolution is sharp when wide open at f/2.8. Even in the Photozone tests (when he finally got a good copy) the 16-50 edge sharpness borders on "poor." Center sharpness is excellent. I found this to be the case in my personal tests as well. The edge sharpness of my Tamron 17-50 at f/2.8 was considerably better than my DA* 16-50 at f/4! CA is also terrible on the DA* 16-50.

Last edited by PentaxPoke; 05-10-2010 at 01:53 PM.
05-10-2010, 01:57 PM   #6
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QuoteOriginally posted by PentaxPoke Quote
Ben,

I'm sorry but I disagree with you on one point. Assuming one gets a good copy of the DA* 16-50, only the center resolution is sharp when wide open at f/2.8. Even in the Photozone tests (when he finally got a good copy) the 16-50 edge sharpness borders on "poor." Center sharpness is excellent. I found this to be the case in my personal tests as well. The edge sharpness of my Tamron 17-50 at f/2.8 was considerably better than my DA* 16-50 at f/4! CA is also terrible on the DA* 16-50.
No problem I think, the 16-50 has some pronounced field curvatore, of which the prominent distortion at the wide end could be an indicator. I usually do not care that much about the frame edges when I use a lens wide open, as I usually then concentrate the focus on a certain spot, which rarely covers the edges. I have not seen any terrible CAs, though - something which would annoy me very much.

But my message was also more going into the direction, that these example images do not really allow a valid assessment of the lens.
Ben
05-10-2010, 02:38 PM   #7
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QuoteOriginally posted by Ben_Edict Quote
But my message was also more going into the direction, that these example images do not really allow a valid assessment of the lens.
Ben
Agreed. Walay, as boring and cliche' as this may sound, to do an assessment of your lens, you may want do the ubiquitous brick wall test or something similar, so you can control the variables.
05-10-2010, 02:54 PM   #8
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QuoteOriginally posted by PentaxPoke Quote
Agreed. Walay, as boring and cliche' as this may sound, to do an assessment of your lens, you may want do the ubiquitous brick wall test or something similar, so you can control the variables.
Okay, guess I'll do that then, I just thought that since with my 50-135mm, all photos I shot are shap except ones out of focus, but with this 16-50mm, the sharpest photos I picked out...still don't seem sharp, so maybe something definetely wrong with this one. But ya, guess I'll do a brick test to make sure.

Please come back to help me again after I got the brick shot photos.

05-10-2010, 03:09 PM   #9
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QuoteOriginally posted by walay Quote
Please come back to help me again after I got the brick shot photos.
I will, but to be honest, I may not be the most impartial judge when it comes to the 16-50. Based on my experience with the lens, even if you got a "perfect" copy, I still believe it is not worth the money. #1 for the potential for SDM failure out of warranty, #2 for the poor edge softness at f/2.8, and #3 for the poor CA behavior. There are much better options for considerably less money. Can you still return it for a refund or exchange?

Is weather sealing that important to you?
05-11-2010, 04:46 AM   #10
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I only recently acquired a DA* 16~50 and so far I am very pleased with it. I fall into that group, I suspect the majority, who got a “good” copy. Like Ben, I find the lens is very sharp in the center and soft at 2.8 but that is not an issue for me. In fact I rather like the effect at 2.8 especially at the 16mm setting. I’m less thrilled with the barrel distortion at this focal length but I can live with it. I was aware of this issue after reading the Photozone review:

“At 16mm the lens shows fairly heavy barrel distortion (~3.6%) - this is slightly higher than average for a standard zoom lens but then we're also talking about 16mm here rather than the usual 17mm or 18mm setting. Beyond the extreme wide-end the distortion is actually very well controlled with slight barrel distortion at 24mm and slight pincushion distortion 50mm.”

To my mind the build quality, overall sharpness, contrast and fabulous colour rendering of the lens make it worth the admittedly high price tag. I would send the lens back if you are not satisfied and keep doing so until you get one which does satisfy you.

Tom G

Last edited by 8540tomg; 05-11-2010 at 05:46 AM. Reason: typo
05-11-2010, 05:38 AM   #11
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Ben and Tom G sums up my feeling of the 16-50

I doubt it's you, Walay that's the problem. Just get it replaced

In my humble opinion, weather sealed is a joy

Nothing beats having the freedom to shoot as and when you want to

I too enjoy those moments when others were busy hiding their gears while I just carry on shooting

The feeling is just so good
05-12-2010, 06:32 PM   #12
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I attached a new jpeg and photoshop file of the comparison with the other lens I have, with all same settings, center focused, and crop from the center point.
I understand about jpeg compression, so I also attached a photoshop file, but the fuzziness and color change are the same.
It always looks like it have a green/yellow tint vs using other lens type..under same W/B ofcourse. no lens filter are used on both lenses.

Since the only closest comparison I have is this manual 50mm and the da*50-135, and both produce really sharp images, after 2 replacements..... I'm really not sure if I expected too much from this lens......or its a bad one again...!@#%$

Last edited by walay; 05-12-2010 at 06:45 PM.
05-13-2010, 04:38 AM   #13
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In your profile, I see you have a K20D. Just a thought but did you use the AF finetuning to correct for back/front focus errors?
05-13-2010, 06:53 AM   #14
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QuoteOriginally posted by walay Quote
I attached a new jpeg and photoshop file of the comparison with the other lens I have, with all same settings, center focused, and crop from the center point.
I understand about jpeg compression, so I also attached a photoshop file, but the fuzziness and color change are the same.
It always looks like it have a green/yellow tint vs using other lens type..under same W/B ofcourse. no lens filter are used on both lenses.

Since the only closest comparison I have is this manual 50mm and the da*50-135, and both produce really sharp images, after 2 replacements..... I'm really not sure if I expected too much from this lens......or its a bad one again...!@#%$
The new example clearly shows the superiority of the 50mm prime - that's clear. But it is still hard to speculate about the origin of the softness of the DA's images. First of all, most zooms will break down in IQ at such short distances and I would say, that the images are en par with some "dedicated macro" zoom lenses we have had posted here lately.

Whether there is a slight misfocus or whether there is an inherent defficiency of the lens, I cannot decide.

I just took a couple of comparisson shots with my own copy of that lens of a similar zipper. Wide open @ f/2.8 there is a slight softness, which is more pronounced towards the edge of the fov, but the center is very sharp. At f/4 the softness in my lens is completely gone and at f/5.6 the image is really sharp. And that at a similar short distance of 1.5ft.

So, my conclusion would be, that your copy of the lens is still not one of the better ones, wheras mine is quite good.

Ben
05-13-2010, 10:27 AM   #15
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sigh...ya, gotta be the lens then, need to replace it again.....really waste of time.
I used manual focus on both lens, and took couple photo with slight changes in distance, and picked out the sharpest of them for cropping......nothing wrong with focus, because i can tell its a different kind of blur when out of focus.

can't believe after 2 replacements...its still not a good copy.

Thank you all for the help~
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