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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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10-21-2008, 09:08 AM   #946
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Pentax 16-50mm with soft left side ?

hi guys,

I just received my 16-50mm and i'm not sure it is a good copy, when i did a Focus Test chart, it show that the left side is less clear than the right side.

I have a K10D btw

here some example:
Exposure: 1/100 sec
Aperture: f/3.2
Focal Length: 50mm
http://picasaweb.google.com/herouxb/Test1650mm#5259635912910609618

Exposure: 1/100 sec
Aperture: f/5.6
Focal Length: 50mm
http://picasaweb.google.com/herouxb/Test1650mm#5259636097823806882

Exposure: 1/100 sec
Aperture: f/9.0
Focal Length: 50mm
http://picasaweb.google.com/herouxb/Test1650mm#5259636306444128594

Exposure: 1/125 sec
Aperture: f/2.8
Focal Length: 16mm
http://picasaweb.google.com/herouxb/Test1650mm#5259434340890267074

EDIT: you can zoom in the image now...

So... what do you guys think ?

thanks!


Last edited by TanGU; 10-21-2008 at 11:03 AM.
10-21-2008, 09:18 AM   #947
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your samples aren't showing.
but if it's what i'm thinking it is, most likely this is an issue with decentering. time to send it in
10-21-2008, 09:38 AM   #948
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Don't waste any more time on the 16-50 merry-go-round. Return the lens, and get a Tamron 17-50.

See links below:

https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/35735-da-16-50...-round-ii.html

https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/29218-tamron-1...throwdown.html
10-21-2008, 09:54 AM   #949
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I did another test:
http://picasaweb.google.com/herouxb/Test1650mm#5259649787558207186

If you compare Lisa and Maggie... is it a good test by the way?


Last edited by TanGU; 10-21-2008 at 11:04 AM.
10-21-2008, 10:21 AM   #950
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Your images are still not visible.
10-21-2008, 11:05 AM   #951
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QuoteOriginally posted by PentaxPoke Quote
Your images are still not visible.
Ah sorry... it is picassa problem, so i include the link instead of showing the image directly, because the URL seem to change
10-21-2008, 11:39 AM   #952
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Looks softer on the left to me. The brick wall shows really bad "mustache" distortion at 16mm. That is typical for this lens though.

To verify you might try a bigger brick wall from farther away so any camera angle affects are minimized.

I agree with k100d about the decentering. Did you look through the two links I posted?

Last edited by PentaxPoke; 10-21-2008 at 12:46 PM.
10-21-2008, 02:19 PM   #953
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replying to your post - looks very similar to mine but in reverse - mine goes out of focus on the right side. Pity - otherwise, the lens seemed to work very nicely.

10-21-2008, 06:37 PM   #954
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Bit of a thread dig up, but yesterday I received this exact lens (serial number 9013560) from (a popular Sydney online retailer) and have come to the conclusion that it is indeed a crap lens and should go straight in the bin.

Right side of the lens is rubbish up to f8 from 16mm to ~35mm, left side is bad at 50mm (how does that work ??).

I have arranged to have this lens replaced but I just thought I'd give this forum a search and see if the serial number popped up... Not real impressed to say the least. I knew something was up when the serial number on the box didn't match the lens and the aperture lever on the lens mount was worn.

Not sure if its against forum rules to "name and shame" but at least this store has been good in replying to my emails and sorting out a replacement. Hopefully I'll get a new lens this time.
10-21-2008, 08:48 PM   #955
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QuoteOriginally posted by Cooties Quote
Bit of a thread dig up, but yesterday I received this exact lens (serial number 9013560) from (a popular Sydney online retailer) and have come to the conclusion that it is indeed a crap lens and should go straight in the bin.

Right side of the lens is rubbish up to f8 from 16mm to ~35mm, left side is bad at 50mm (how does that work ??).

I have arranged to have this lens replaced but I just thought I'd give this forum a search and see if the serial number popped up... Not real impressed to say the least. I knew something was up when the serial number on the box didn't match the lens and the aperture lever on the lens mount was worn.

Not sure if its against forum rules to "name and shame" but at least this store has been good in replying to my emails and sorting out a replacement. Hopefully I'll get a new lens this time.

Now that is a big concern.

I have long wondered what happens when lenses are returned. How easy it would be just to pop it back into a box and send it off to the next person.

The lady from Adorama assured me that they (Adorama) would not do this as they had a policy of shipping un-opened boxes only.
I found this out only after asking her if someone at Adorama would open the box, take some shots with the lens and email the shots to avoid exactly this situation. Not unsurprisingly that request was refused, and thats when the shipping policy came to light, from that particular store.

It is sad and dis-appointing to hear your story, and yes, I think you have every right to name. Afterall, they all enjoy the praise when its being offered.
10-21-2008, 11:32 PM   #956
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I too would name and shame.

If they come to the party and replace with a good one then name and fame them



Neil
10-22-2008, 04:24 AM   #957
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QuoteOriginally posted by PentaxPoke Quote
Looks softer on the left to me. The brick wall shows really bad "mustache" distortion at 16mm. That is typical for this lens though.

To verify you might try a bigger brick wall from farther away so any camera angle affects are minimized.

I agree with k100d about the decentering. Did you look through the two links I posted?
It weird isn't it? because it is not a front or back focus problem that everyone seem to complain about this lens, maybe a new problem?

I read your post, but the Pentax is better to me because of it sealing... thx anyway
10-22-2008, 05:23 AM   #958
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QuoteOriginally posted by TanGU Quote
It weird isn't it? because it is not a front or back focus problem that everyone seem to complain about this lens, maybe a new problem?

I read your post, but the Pentax is better to me because of it sealing... thx anyway
It's definitely not a new problem. There are many threads discussing this "decentering" problem. I've gone through two bad copies from an ebay seller recently. Both had this same problem, mushy on one side. Didn't even get to test the front/back focusing, just sent them back.

I'd really like to find a perfect copy of this lens, but am losing hope.
10-22-2008, 06:06 AM   #959
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QuoteOriginally posted by Matt Miller Quote
It's definitely not a new problem. There are many threads discussing this "decentering" problem. I've gone through two bad copies from an ebay seller recently. Both had this same problem, mushy on one side. Didn't even get to test the front/back focusing, just sent them back.

I'd really like to find a perfect copy of this lens, but am losing hope.
ah... so that a "decentering" problem... okay i didn't know what it mean.

I'll do some other test tomorrow with a tripod and real life test shot to see if it is really bugging me that much

Btw, i won't buy that lens on ebay if i were you...try in store (like me! haha)
10-22-2008, 11:04 AM   #960
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For anyone who sent their lens back for replacement, how many replacements is it taking before you got a good one? Mine is off at the right edge but tolerable if I don't need to use the right 10% of the shot and crop it out.
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crop of centre: Name:  inlet-centre.jpg
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Last edited by John K; 10-22-2008 at 11:20 AM.
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