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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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03-30-2008, 09:03 AM   #601
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QuoteOriginally posted by thePiRaTE!! Quote
Not sure why it was wrong for the guy to verify his dads expensive purchase with others, especially given the track record of the lens in question and the obvious soft results. The shot you've shown is fine for soft edges, in fact, it would probably help center attention toward her eyes, but if your shooting landscapes or architecture for example you want to know you have the best example you can get for the edges. If he can expect better for his money, I think thats all he's trying to find out.
The problem is that soft edges aren't any worse than the BEST from the other brands best lenses that cost more. Everyone has blown this lens way out of the water with their dumb chart tests. Of course the edges are soft, look at the top three 16/17-50/55 2.8's they all have soft edges and corners. I had an amazing copy of the 28-75 2.8 tamron and people compare it to that lens and of course the borders are better it starts at 28mm, but it ain't sharper at 2.8 than my DA* 16-50. The 16-45 f4 is sharper in the corners at f4 because again it's a shorter zoom ratio which is easier on distortion which helps corner sharpness. The best landscape lens for Canon has always been the 17-40L f4, not any of their f2.8 lenses. But again landscapes who cares if the corners are soft... so the sky or grass is a little blurry at the corners its a sky...

Whats funny is the sharpest lens in the category for extreme and corner sharpness is the Tamron 17-50 f2.8 even over the L glass and Nikkor stuff. The problem with that lens is the curvature distortion. It makes things bend in the enges, but shows sharpness. Not sure which I want, but if I want a fast focusing, quiet, sharp, weather sealed lens the DA* 16-50 is stellar and at a very very fair price.

It's utterly pointless to run lenses through these tests unless you find the center as being awful because the majority of your picture is in the center, not the 25% in the corners and extreme borders.

Now architecture I can understand worrying about borders because your lines and angles have to run from edge to edge. So I would purchase a 12-24 f4 because it's the best one for distortion correction as well as being a stellar lens.

03-30-2008, 10:12 AM   #602
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Good to know how the 16-50 sits among the competition, and what to expect from zooms in this class at least. Your experience on that matter is beneficial.

With all due respect Codiac, I would say if I had continuous access to all these lenses as you may have at the store, its something you could slowly come to realize with use, how these lenses are on averages. In defence of the OTS, if you're consumer who bought a lens and had a hunch, there is really only one way to find where you sit in that average - dumb chart test and ask for opinions. I'm not sure the original intent was blow the lens out of the water. I would also be curious to know if his pics are average for the lens?
03-30-2008, 10:34 AM   #603
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.

Well said codiac.

If your 16-50 misses center focus a lot of the time, you have a bad one. If AF is accurate and tack-sharp in the center at f4 and still very sharp at f2.8, you have a good copy.

I'm really starting to love my 16-50. It's my most used lens now.

If you don't want the headache of possibly sending it back, go with the 16-45 f4, by all accounts an excellent lens.
03-30-2008, 12:25 PM   #604
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From PENTAX Digital SLR - The New Classic
The smc PENTAX-DA* 16-50mm f/2.8 ED AL[IF]SDM wide angle zoom lens delivers the highest level of optical quality and includes SDM technology for fast, accurate, quiet focus. Bringing together advanced optical technologies, including aspherical elements, special optical-glass elements and original lens coatings, these new interchangeable lenses are superior to any existing lens series in terms of contrast, clarity and edge-to-edge sharpness.

Thus, expecting edge to edge sharpness is a reasonable expectation.

03-30-2008, 02:26 PM   #605
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QuoteOriginally posted by selar Quote
From PENTAX Digital SLR - The New Classic
The smc PENTAX-DA* 16-50mm f/2.8 ED AL[IF]SDM wide angle zoom lens delivers the highest level of optical quality and includes SDM technology for fast, accurate, quiet focus. Bringing together advanced optical technologies, including aspherical elements, special optical-glass elements and original lens coatings, these new interchangeable lenses are superior to any existing lens series in terms of contrast, clarity and edge-to-edge sharpness.

Thus, expecting edge to edge sharpness is a reasonable expectation.
The edges are fine, corners not so much. And it's edge and corner sharpness is better than many of the lenses the competition have. They worded that statement for all there DA* lenses. Not so accurate, but thus is the industry.
03-30-2008, 02:38 PM   #606
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I agree that corners are not so important, I don't think its reasonable to expect a zoom to act like an ultra wide prime, the OP's lens is borderline but not stellar. I'd probably think quite a bit before sending that copy back for service.

Mine was much worse, even the centre had blurred edges upto f8.

Brick wall and newspaper shots are not a good test, real world shots within a reasonble DOF range are.
03-30-2008, 02:52 PM   #607
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Let's get serious about "edge-to-edge sharpness."

The Nikkor AF-S 17-55mm f/2.8 G IF-ED DX (a VERY good lens) has the following sharpness (as tested using Imatest) in terms of line widths per picture height (LW/PH) which is widely considered the standard "technical measure" of sharpness.

@ f2.8 and 17mm:
Center: 2114 LW/PH
Edge: 1565 LW/PH

The Canon EF-S 17-55mm f/2.8 USM IS gets this:

@f2.8 and 17mm:
Center: 2061 LW/PH
Edge: 1625 LW/PH

I don't have the test results from the DA* 16-50mm, but here are the results from the SMC-DA 16-45mm f/4 ED AL:

@f4 and 16mm:
Center: 2281 LW/PH
Edge: 1741 LW/PH

For a little context, the "cheap-o" Pentax SMC-DA 18-55mm f/3.5-5.6 AL (version I) has the following performance (keep in mind this lens was replaced with the version II that has better edge sharpness).

@f3.5 and 18mm:
Center: 2102 LW/PH
Edge: 1451 LW/PH

My point? The Canon lens and the Nikon lens both sell for $1,400 retail and don't have any substantial edge sharpness advantage over a cheap Pentax "kit lens" that itself was replaced by Pentax for poor edge-to-edge sharpness.

Are the Nikon and Canon lenses still worth $1,400? You better believe it. Why, because there's more to judging a good lens than edge sharpness.

Regardless, my earlier point remains ... if you believe the DA* 16-50mm is junk, then it is junk. Use whatever works for you. It's like my old Sociology professor used to say back in my college days, "Reality is whatever the individual believes it to be. If someone truly believes 2+2=5 then that is REALITY for that person."

If you believe that a good lens is a lens that gets 2250 LW/PH at center and 2250 LW/PH at the extreme edge then that is what makes a good lens.
03-30-2008, 05:07 PM   #608
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hehe, JJJ, the OP just asked for an opinion. Everything else was invented by everyone else. Nice to know Pentax fares well against the competition though!

03-30-2008, 06:42 PM   #609
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i can say that the one that I briefly had with the K10d was crappy *everywhere* in the frame. I shot real world back to back with the 18-55 kit lens and the 16-50* lost most every shot. Auto or manual focus. I clearly (pun intended) had a bad one. I didn't need to (and never do) shoot a newspaper to figure that out.

My 50-135 is amazing. So is my 16-45. In fact the 16-45 is so good that I can't rationalize buying the 16-50* unless I have to shoot wide in the rain.

If I didn't have the 16-45, I'd be looking for a 16-50* though. I have faith that they all aren't bad.
03-30-2008, 07:18 PM   #610
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I can understand the purpose of this thread. Being a DA* class, buyers expected a lot from this lens. Thus, when they got a bad one, they would more vocal about the issue. I am usually not interested in zoom, but even then I was aware of the problem . So when the need arose for a DA* 16-50, I couldn't help myself but to do the same dumb newspaper test. However, the result turned out to be better than expected. I plan to use this in a wedding so for the purpose, the result I got would be fine.

However, for flat work shooter, I think they do see the need to question the quality of the lens. It simply comes to what is the people's intention for this lens and their expectation. It's like back in the day when we have split opinion about the FA* 24. Some vouched by it, while some wouldn't even want to touch it.

Besides, it seems like the poster didn't really know what to expect from a good copy of the lens. He's trying to learn the normal behavior of the DA*.
03-30-2008, 09:19 PM   #611
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QuoteOriginally posted by JJJPhoto Quote
Regardless, my earlier point remains ... if you believe the DA* 16-50mm is junk, then it is junk. Use whatever works for you.
Could you please direct me to an eairlier post where I actually said this lens was junk?
I did say that if it was me I would be inclined to try another copy, but also saying that I would hate to send it back if this was actually a good copy, depending on what members thoughts were.



I belive that some people can become defensive when equipment quality is questioned & this thread was never ment to trash the DA* lens in gereral.

I could have simply put my opinion of this lens in the DA*16-50 Serial Number Database and be done with it.

Instead I decided to take the time & effort to post the results of this particular lens to give it the benefit of the doubt.
That way members who have had a bad run with this lens or thoes who have a good copy can give their input as to weather it's keeper a or not.

My father mainly shoots landscapes 95% of the time, and he does use primes for this purpose sometimes.

Thank you all for your input.

Cheer

Del
03-31-2008, 04:15 AM   #612
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QuoteOriginally posted by VHDEL Quote
Could you please direct me to an eairlier post where I actually said this lens was junk?
Post #22 in this thread:

"If someone thinks a lens is junk then it's junk (for them)."

I hope you don't think that any of my comments are meant to be a personal attack. Because that's not my intention at all. There have just been so many people in these forums who have complained about the lack of edge sharpness in the 16-50 that I've started to feel like people are developing unrealistic expectations. Particularly given the fact that we have to crop extreme edges of the frame for prints ... and uncropped images usually aren't shown at 100 percent magnification online unless it's for a test like this.

Even a great prime like the DA 70 Limited (a lens with great edge-to-edge sharpness) still gets softer at the extreme edges compared to the center:

@ f2.4:
Center= 2059 LW/PH
Edge= 1839 LW/PH

Even a great prime, a lens that doesn't have to make compromises in the optical design in order to reach multiple focal lengths, gets softer at the edges. Zoom lenses (even great zooms) get even more soft at the edges ... it's one of the sacrifices you have to make in order to have the convenience of multiple focal lengths on one lens.

My Sigma 24-70mm f/2.8 DG (my favorite zoom) only gets the following level of sharpness wide open and at the shortest focal length according to Imatest.

@ f2.8 and 24mm:
Center= 1945 LW/PH
Edge= 1641 LW/PH

My point is not to attack you or anyone else who thinks the DA* 16-50mm doesn't perform well. My point is that not every lens is the best tool for every photographer. You just have to use what works for you. I just want to make sure people don't expect "edge-to-edge sharpness" to mean "this lens is perfect at the center and perfect at the extreme edges."
03-31-2008, 07:03 AM   #613
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QuoteOriginally posted by JJJPhoto Quote
Post #22 in this thread:
"If someone thinks a lens is junk then it's junk (for them)."
Thank's for clearing that up JJJ,
I was affraid this thread was starting to head downhill with to much emphasis on type of test & expectations from it.
I'm aware that it's to much to expect a lens to be sharp edge to edge, my fathers tested enough of them over the last 30yrs.
He's had his fair share of dog & stellar lenses including FA*.

Whatever he decides to do with his lens is up to him, I will most probably get this lens along with the 50-135.
If the 16-50 I get is a keeper, then I can sell my Sigma 24-60 F2.8.
Eventually sell the K10 along with the Sigma 17-70 to purchase a K20
I guess I'm not realy into the LBA thing

Thank's everyone.
03-31-2008, 07:35 AM   #614
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I have a bit of experience with this lens as I have tested 3 of them quite carefully. The first two lenses I received had centering defects similar to the defect that your tests demonstrate. The third lens had no significant centering defect and so I kept it and have already produced some very nice photos with it. I would return that lens and insist on better. These lenses are not cheap and they should perform better than what you have shown when they are built properly.

Ted
03-31-2008, 07:45 AM   #615
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Keep returning until you get a winner, because when you do, you will be happy you did. I had some frustrations as I had to return this lens twice before getting a superb lens. My lenses had a problem with centering defects, not with focus. I would not trade my current DA* 16-50mm for anything. The color, contrast, and sharpness are amazing and the weather-sealing held up in very wet and very dusty conditions. There is no excuse for the horrific QC that Pentax has shown with this lens, however. Keep on pluggin and you will be rewarded, eventually.
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