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Old Aug 24, 2009, 10:31 PM   #1
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Default DA*16-50 Decision Time

Well, I tested the replacement lens at lunch time. Focus wasn't bad, occasionally off but that could have been me more than the lens, or it might have needed a slight focus adjustment. Center was really sharp, I can see why those who have good copies love the lens. Unfortunately, this one is definitely decentered, blurrier on the right side (significantly so). I'm really disappointed as I thought at first I had a good one (my first one wasn't sharp anywhere, and only slightly blurrier on the left side).

Now it comes to decision time - I chose to buy this lens at this time because it and the 10-17 are on the K-7 rebate list. I can only send in once for the rebates, and it has to be done within 30 days of purchase. You have to send in the bar codes from the lenses. So my choice at this point is to return the lens, ask for a refund and send in the rebate on the 10-17 only, forgetting about the 16-50 completely. Or keep this lens, send in for both rebates and pack the lens off to Pentax repair. I don't have enough time to go through the exchange process again with B&H before the 30 days runs out on the 10-17. My thought yesterday was to skip the 16-50 right now, maybe buy it again in a year or two and continue to skip the kit lens range. However, now that I've seen what the center sharpness is capable of, I'm leaning toward keeping it and sending it in for repair (knowing that it will most likely be 6 weeks or more before I'll see a lens again). I can see glimmers of how this lens could be really, really nice and it sure would be nice to add it to my other weather sealed lenses (could have used it Saturday).

Any suggestions or thoughts one way or the other?
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Old Aug 25, 2009, 1:24 AM   #2
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After receiving another faulty copy of the lens from Pentax repair, I decided to check out a camera store w/ a 16-50 that I could play with. After deciding it was a good copy, I bought it. A double-check with the focus chart does show the focus is in the right places, so I indeed have a good copy. My rebate request is out the door, along with the faulty replacement I still have (once I get a working replacement I'm going to sell it and keep my good one).

I <3 this lens way too much to not have one. It's my main walkabout lens, great for indoors and especially outdoors (makes me crazy enough to use inside a pool, as shown below):

Video: http://www.youtube.com/watch?v=OqmYa_khvbM

- Jason
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Old Aug 25, 2009, 7:30 AM   #3
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Sounds like the Pentax/Tokina collaboration has some quality control issues (at least with this lens). It seems that at this price point that is not acceptable. Hope you get a good working lens, the 16-50 is far more useful than the 10-17 (although the 10-17 can be great fun and is very sharp).

Good luck

BTW you have quite a lens collection now Harriet, a far cry from just a few years ago with a superzoom p&s
Riverview, NB, Canada
Current equipment
Pentax K7, K5, K3:
FA 35mm f2, FA 50 f1.4, FA 28-70mm f4, FA 28-80mm f3.5-5.6, F 50mm f1.7, Tamron SP 70-200mm f2.8 Di, DA 10-17 f3.5-4.5, DA 14 f2.8, DA 16-45mm f4, DA 18-55mm 3.5-5.6 WR, DA 50-200mm f4-5.6 WR, AF-540FGZ

Olympus E-PM1, E-PL1, E-P2, E-P5: 9mm to 150mm lenses


Last edited by Monza76; Aug 25, 2009 at 7:32 AM. Reason: Question
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Old Aug 25, 2009, 7:45 AM   #4
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I believe you have already decided...in cases like this, one's first option is most likely the one you have already decided on!

As for me, I'd return it and get my money back if for no other reason, to send the manufacturer (Pentax in this case) a message that bad product = no sale!

I'm fortunate that I own a good version of this lens and similar to Jason, have been hard pressed to remove it from my K20D!
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Old Aug 25, 2009, 3:42 PM   #5
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I'd send it back and forget about it - you have too many other good lenses to put up with this kind of nonsense. It is not like you couldn't live without it - there must be other options. There are too may bad copies of this lens being turned out - as Jalpee implies (although not said in as many words), Pentax needs to realize they can't rely on internet sales alone if they continue to put out unreliable products - even the internet sellers will cut them off if they get too many returns.
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Old Aug 25, 2009, 10:22 PM   #6
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Send it back Harriet, it wouldn't be worth it to me after the second bad copy, which would make me loose interest at a high rate of speed in that lens.

Break out some good glass and have some fun taking photos instead of dealing with the frustration of wondering if your new copy will be up to your standards!

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Old Aug 25, 2009, 11:04 PM   #7
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I'm on the fence with the lens. Here are some examples - jpg straight out of the camera, the resized versions have been resized by zenfolio and I've put links to the full sized files. I would appreciate any feedback from them. You can see that I wasn't paying all that much attention to exposure, I was looking more for things that would help me decide if the lens has a problem or not.

First, it's center sharpness is excellent - it sure captured my interest:

full sized: http://mtngal.zenfolio.com/img/v1/p820817536.jpg

A silly street scene. The last distance marker on the lens before infinity is 7 feet, I think, so except the car closest to me everything else should be in focus. Notice the face in the car window.

full sized: http://mtngal.zenfolio.com/img/v4/p944562976.jpg

Reflections of tall buildings:

full sized:http://mtngal.zenfolio.com/img/v0/p810237425.jpg

Take a look at this one full sized - you can clearly see the texture of the panels the lettering is mounted on:

full sized: http://mtngal.zenfolio.com/img/v4/p929414491.jpg

You can also see how the sides are a bit blurry, the right side looks blurrier to me than the left side.

The lens is much better than the last one I had. It's so good in the center, I'm really tempted to keep it, thinking that I could live with the sides. I take lots of pictures like this one, and I'm pretty happy with it:

full frame: http://mtngal.zenfolio.com/img/v1/p545134998.jpg

When you look at it full size, it doesn't look as good, at least on the sides. Am I asking too much of the lens, to have more sharpness across the frame? I may be asking too much, except for my macro lens, no other lens has the same center sharpness at the edges. It's just that this one has more blurriness than the 12-24 has, and I would expect as a * lens, it should at least match it's sharpness.

If you are interested, here's links to three newspaper shots (tripod mounted, flash) and a brick wall:

16mm: http://mtngal.zenfolio.com/img/v3/p891465709.jpg
31mm: http://mtngal.zenfolio.com/img/v4/p878244330.jpg
50mm: http://mtngal.zenfolio.com/img/v0/p884508295.jpg

Brick wall:


I was square to the brick wall, but was hand-holding the camera. If I were to judge by the brick wall, the lens would already be on its way back. But then I look at the newspapers and think it's marginally OK. I looked at the lily (first picture) and see why people swear by the lens.

Is this the typical norm for this lens? Or do I really have a not-so-good copy? I can't say its horrible, its significantly better than the other one I had. But I'm not so sure I can say it's defective.
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Old Aug 26, 2009, 6:42 AM   #8
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Harriet, You know I'm no pro at any of this, but if I were you I'd return it. You will always be second guessing if your images came out okay or not. Yeah, you're going to lose the benefit of the rebate, but look at all the other lenses you got good buys on.

Anyway, just my opinion.

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Old Aug 26, 2009, 10:23 AM   #9
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I've been watching the posts here about the K7 for some time, while considering the possiblity of selling my Minolta lenses and buying into the Pentax fold. I've been very pleased with my Tamron 17-50mm f/2.8 lens and was wondering what the attraction was for the Pentax 16-50/2.8. From what I can see, it has less vignetting wide and wide open, but more under all other circumstances. It's way less sharp at the edges, and it costs twice as much.

Can someone fill me in?
  • The lens is the thing.
  • 'Full Frame' is the new 'Medium Format'.
  • "One good test is worth a thousand expert opinions." - Tex Johnston, Boeing 707 test pilot.
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Old Aug 26, 2009, 11:07 AM   #10
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I don't know how much you can always expect a wide angle zoom lens to deliver a truly flat field, given the curvature of the elements, the complexity of the computations involved in the designing, as well as the tolerances needed in manufacturing. The Tamron is available in Pentax mount at $345 and may be a better alternative given the QC problems with the Pentax lens. The same basic lens as the Pentax is available from Tokina in Canikon mounts - I wonder if they have been having the same problems, or if any Pentax specific modifications could be at the root of it?

TCav, I have both systems, but for some reason I find myself preferring to use the Pentaxes more. Both systems are good - perhaps I am more comfortable with Pentax - I like the top display panels and the control layouts better, and even the friendliness of this forum encourages me to post here more than elsewhere. The K20 and K7 (although I haven't sprung yet for that one) are all one could ask for at this stage of the technology, short of full frame (for which I feel no need).
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