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08-16-2008, 08:44 PM   #166
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For most of usual scenes - you not need the sharp edges:



08-16-2008, 10:16 PM   #167
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Are you saying that we should just accept a clearly defective lens that costs over $700? And that is a good idea why?
08-16-2008, 10:47 PM   #168
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QuoteOriginally posted by PentaxPoke Quote
Are you saying that we should just accept a clearly defective lens that costs over $700? And that is a good idea why?
I bought this lens for the 1200 U$, but it is not important I think if look defect in each of your lens, at 99% you will find Some people wrongly testing the lens, or have a problem with the camera AF.
08-16-2008, 10:56 PM   #169
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Maybe this link will help for some tests:

Jeffrey Friedl’s Blog Jeffrey’s Autofocus Test Chart

08-17-2008, 07:29 AM   #170
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QuoteOriginally posted by PentaxPoke Quote
Are you saying that we should just accept a clearly defective lens that costs over $700? And that is a good idea why?
Actually, mine cost under US$570 after rebate.
08-17-2008, 10:19 AM   #171
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Is it just me or does this lens appear to have nothing but good copies for a month or 2, and then a string of duds for a month or 2

2 weeks ago I was thinking that the problems were over (or is it hoping) and now I see that I was wrong

I must admit that I love some of the photographs I've seen taken with it, but at this point I wouldn't even consider asking my camera guy to order one in.
If it was a dud purchased here in Canada I might have a problem trying to get it fixed, or replaced. (Pentax Canada isn't as good as elsewhere)
08-17-2008, 11:12 AM   #172
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QuoteOriginally posted by suro Quote
Maybe this link will help for some tests:

Jeffrey Friedl’s Blog Jeffrey’s Autofocus Test Chart
Suro,
I think you misunderstand the type of defect people have been having with this lens. A focus test chart like that will not reveal the problem. That is only for determining FF or BF. (BTW, I thought you said people should be taking "usual scenes" ) The problem is with asymmetric focussing across the field of view (decentering), or with doubling or very poor focus at the edges while being sharp in the middle. These have nothing to do with the AF of the camera. They are entirely lens aberrations (defects). I own 8 lenses for Pentax DSLR's, and none of them have had defects except for my DA* 16-50. I have had to send two 16-50's back so far. I posted my latest example here: https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/34507-my-da-16...hapter-ii.html
Those example pictures were perfectly sharp in the center, but the borders were so bad at all apertures, that my cheap P&S looked better than this "premium" lens.

Last edited by PentaxPoke; 08-17-2008 at 11:24 AM.
08-17-2008, 02:15 PM   #173
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The photographs from PentaxPoke's last copy were probably the worst that I've actually seen.

For a moment I actually though it must be something wrong with my eyes, I almost felt dizzy instantly.
Which I didn't think was possible from a photo until then.

08-17-2008, 07:50 PM   #174
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QuoteOriginally posted by PentaxPoke Quote
Suro,
IThe problem is with asymmetric focussing across the field of view (decentering), or with doubling or very poor focus at the edges while being sharp in the middle.
Back and front - is one of problems with softer center

Asymmetric focussing across the edges - depends on the size. For crop lenses similar problem as the lens for full frame camera optic (softer edges and vignette). Also, the test must be photographed with a camera tripod and stand on the level (I mean - the wall can be curved, or camera).

P.S. Not sure for my English
08-17-2008, 09:08 PM   #175
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QuoteOriginally posted by little laker Quote
The photographs from PentaxPoke's last copy were probably the worst that I've actually seen.

For a moment I actually though it must be something wrong with my eyes, I almost felt dizzy instantly.
Which I didn't think was possible from a photo until then.
I was feeling the same thing. I thought it was just due to my anger at having to send yet another DA*16-50 back due to manufacturing defects.
08-19-2008, 12:03 PM   #176
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QuoteOriginally posted by little laker Quote
If it was a dud purchased here in Canada I might have a problem trying to get it fixed, or replaced. (Pentax Canada isn't as good as elsewhere)
I've been wanting this lens since the day I bought my first K110.

Now that I can afford it I am terribly hesitant due to that exact reason... Pentax Canada service is awefull (or downright inexistant) and so many duds of that lens are out there. I am not sure I want to take a chance on a $700 lens.

Pat
08-19-2008, 12:34 PM   #177
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Hi Pat,
You can buy the 16-50 from one of the reputable merchants, e.g B&H, test it and, if it's bad send it back for exchange. You have about 70% probability of getting a good one.
Sorry for bad Pentax service in Canada. I used Pentax USA and didn't have any problems.
As for the lens - like it very much and have a lot of fun.
08-19-2008, 01:52 PM   #178
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I took the plunge and risked buying this lens online from B&H USA as it's price in Aust is far to much.

Despite the posts on bad copies the good reports on this lens outweighed the downside. I received a good lens that has exceeded my expectations

This now is my favourite lens... love it.


Neil
08-19-2008, 02:29 PM   #179
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After 2 duds I took a few months off, and just ordered my third copy of this lens (hopefully it's the "charm" as they say). Somebody bought one of the ones I returned as refurbished and it was fixed by then....

Luckily it's pretty risk free here in the states. Amazon is great for returns, they even pay return shipping, so while a bit of a hassle - a bad copy isn't that big of a deal to me. At this point I'm just going to keep trying until I find a keeper. My lastest attempt shipped today, so here's hoping!
08-19-2008, 06:28 PM   #180
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I got mine today and the SDM wasn't working.
S/N: 9018887
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