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07-07-2012, 05:47 PM   #1
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DA* 16-50mm: is mine a duff copy or par for the course?

Just taken delivery of a brand new DA* 16-50mm. With some trepidation. I suspect the trepidation was justified.

Apologies in advance for the brick wall shots.

First thing I noticed was that the lens produced different exposures at different F-stops. To illustrate, compare this shot at F2.8:

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with this one at F4:

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The F2.8 is overexposed by 0.7EV (I tested it). Having to dial in exposure compensation when changing aperture doesn't strike me as very convenient, to say the least.

Now, I didn't expect extreme sharpness wide open, but I looked at the F4 shot (and an F5.6 shot too) and thought "that looks plain soft to me". To illustrate, here's a 100% crop from the centre of that F4 shot:

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Compare it with a centre crop taken by the Tamron 17-50mm at F4:

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I'm no pixel peeper, but I expected good centre performance from the Pentax. The Tammy absolutely slays it to a degree far greater than expected. Gallingly, I sold the Tamron to help pay for the Pentax.

So have I got a duff copy, or is this how the lens performs? Either way, it's got to go back. Shame, because I really wanted to like it.

07-07-2012, 05:51 PM   #2
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I don't know what to say Quark, but the 16-50 is not really praised for in it's wider apertures for sharpness, in fact in my opinion it's kind of terrible. From my experience with my old DA* 16-50 which I last used 2 1/2 years ago, it starts to become really sharp at f/7.1... aside from the weather-sealing and silent AF motor, the Tamron 17-50 f/2.8 is in my opinion the way to go. But however don't agree with me completely by making your decisions to revert back to your Tamy, wait for more replies and see what they have to say.
07-07-2012, 06:28 PM   #3
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You know, I had 3 copies of this lens, which were all subpar, and I finally gave up. Having said that, I have to say this is the worst one I have seen in terms of picture quality. There is something fundamentally wrong with this lens, although I don't know what it is. I agree with LeDave that some people feel that this lens is not known for sharpness at the corners (I am one of them). I would send this one back in no time.
07-07-2012, 06:40 PM   #4
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Although I agree the Pentax doesn't look good in the cropped shot, the Tamron crop isn't near as much of a crop as the Pentax so it is a little hard to compare. Could you put the Tamron one back up and crop the same so I can compare. I have the Pentax and use it as my daily lens, when my shoulder is better, but my wife is using it on the K20D and shooting some macros with it and is quite happy. She normally shots the Sigma 105 so she knows sharp. Yours does seem to not be focusing spot on. Have you tried manual and not using the cameras indicator and see if something like that is off?

The exposure I can't comment other than I usually am under and over exposing all the time on manual as I am trying for that creative shot and use the camera meter as a guide only.

07-07-2012, 06:41 PM   #5
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QuoteOriginally posted by LeDave Quote
From my experience with my old DA* 16-50 which I last used 2 1/2 years ago, it starts to become really sharp at f/7.1... aside from the weather-sealing and silent AF motor, the Tamron 17-50 f/2.8 is in my opinion the way to go.
I already have a weather sealed standard zoom that is sharp at F7.1; it's the one that came with my camera and it didn't cost me 650! And I now regret selling the Tamron.

QuoteOriginally posted by Fontan Quote
I have to say this is the worst one I have seen in terms of picture quality. There is something fundamentally wrong with this lens, although I don't know what it is.
I did wonder whether I had an FF / BF issue, so I printed off Tim Jackson's focus test chart, set up my tripod and found that it focused perfectly, so it wasn't that. I've just mailed the store to ask about returning it for a refund. Glad I didn't buy it second hand!
07-07-2012, 06:59 PM   #6
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QuoteOriginally posted by AussieTrev Quote
the Tamron crop isn't near as much of a crop as the Pentax so it is a little hard to compare.
They're both 100% crops. If I cropped the Tamron shot more, you wouldn't get more detail. The shots are at different focal lengths (35mm Pentax, 24mm Tamron), but both at F4, which I figured was more germane when asking about sharpness. The Pentax shot was also taken from a slightly closer distance, but still a lot further than minimum focus distance. Given that it was closer, I'd expect to see more detail, not less.

I no longer have the Tamron lens, otherwise I'd have posted identical shots.

QuoteOriginally posted by AussieTrev Quote
The exposure I can't comment other than I usually am under and over exposing all the time on manual as I am trying for that creative shot and use the camera meter as a guide only.
I don't necessarily expect perfect exposure from the camera's meter, but I do expect consistent exposure. This was the first time I'd seen this behaviour. I'm guessing maybe that something in the lens isn't communicating something correctly to the camera body and that maybe this same something is responsible for the crappy picture quality.
07-07-2012, 07:11 PM   #7
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Real World Use 16-50, happy

I have a 16-50 that I brought second hand for a little under half price. So a good deal there.

I brought it so I could have a good WR walk around lens for when I travel. I have recently returned from a 3 week trip to the Nordic countries where I took the 16-50 as my main walk around lens (also had a 55-300. 35/2.8 limited and 21 limited with me). I was very pleased to have the 16-50 on the wet days, and also indoors in low light where I wanted 16mm wide. I also have a 14mm prime, but decided the 16-50 was sufficient to cover wide, and left the 14 behind.

I was happy with the shots I got with the 16-50. I have attached 4 examples below - two from the Russian Orthodox Cathedral in Helsinki, one from the Lutheran Cathedral in Turku and one from the Castle in Turku, Finland. The point being the stuff we often complain about with lenses isn't as relevant when shooting real world, or at looking shots taken. Shots are all 16MP Jpeg with very minor PP

Of the 5100 shots I have currently taken with the 16-50, 1722 (33%) have been at f2.8 - mainly indoors and many in low light in various forts, castles, churches and palaces on the recent trip to Finland, Estonia, Sweden and Denmark.

Whilst I know the 16-50 has a lot of detractors, like all things - it is a matter of the compromises on the day with the lenses at your disposal.

I have found in real world use the 16-50 holds up reasonable well. It clearly isn't as sharp as my 35/2.8 limited, and has no where near the micro-contrast detail of my Zeiss 35/2 but then the 35's have compromises as well, as they often aren't wide enough, and nor are they WR.
Attached Images
View Picture EXIF
PENTAX K-5  Photo 
View Picture EXIF
PENTAX K-5  Photo 
View Picture EXIF
PENTAX K-5  Photo 
View Picture EXIF
PENTAX K-5  Photo 

Last edited by NZ_Ross; 07-07-2012 at 07:17 PM.
07-07-2012, 07:18 PM   #8
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NZ Ross you probably have the best copy of the DA* 16-50 f/2.8 I've ever seen, however this type of copy could take a long time to acquire, as Fontan said he had 3 total copies of this lens. Plus mine wasn't even close to yours at f/2.8 at all. Looks like you got a real gem to keep for as long as the SDM keeps moving. Pentax REALLY has to do something about this lens, seems like every copy is not the same at all, some serious QC and manufacturing problems right here.

07-07-2012, 07:18 PM   #9
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Mine gets sharp around f5.6. Can't comment on comparability to the tamron or sigma equivalent. But yeah I wouldn't pixel peep with it.
07-07-2012, 07:23 PM   #10
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QuoteOriginally posted by LeDave Quote
Looks like you got a real gem to keep for as long as the SDM keeps moving
LeDave, it is the SDM that worries me to be honest. As long as it keeps working I will be happy.

I have been wondering what all the gripes around the 16-50 have been about, but if I have been lucky with a really good copy - at least you can see what a good one is capable of.
07-07-2012, 07:39 PM   #11
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@NZ_Ross Lovely shots there!

I bought the 16-50 for the same reason as you. I recently went away to a festival with a couple of limiteds and found constantly swapping lenses to be a bit of a pain. So I figured I'd get a standard zoom that was an upgrade from the 18-55 (it's OK outdoors, but indoors F5.6 @50mm is too limiting in my experience). I tried the DA 17-70 but that was DOA so I wasn't inclined to try that again. Then the Tamron 17-50. Silly, I know, but I really didn't like little things like how the focus ring spun when the lens autofocused. And it felt and looked kinda cheap.

So I persuaded myself that I really needed the next one up. Weather sealing, silent focus, blah, blah. I knew that some people had issues with theirs and I knew also that I'd be taking a slight step down in IQ, but I bought it with a truly open mind. I'm no measurebator, honest, but I do want at least acceptable sharpness. However, the pictures that I'm getting don't just look soft at 100%, they look soft on my computer screen.

I'm really disappointed which is why I'm asking whether I've got a dud or whether "the lens is within factory specifications".
07-07-2012, 07:41 PM   #12
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16-50 to 35/2.8 Real World Comparison at f2.8

QuoteOriginally posted by NZ_Ross Quote
I have found in real world use the 16-50 holds up reasonable well. It clearly isn't as sharp as my 35/2.8 limited, and has no where near the micro-contrast detail of my Zeiss 35/2 but then the 35's have compromises as well, as they often aren't wide enough, and nor are they WR.
Just by way of comparison I have added a couple of images from the Russian Orthodox Cathedral in Helsinki taken with my DA 35 Macro Limited. These are also 16MP Jpeg taken at f2.8 with the K-5, with minimal PP.

I think they are sharper, and contain more detailed information than the 16-50 - but then the DA 35/2.8 Limited is a superb little lens, and this is also the advantage of good primes over zooms
Attached Images
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PENTAX K-5  Photo 
View Picture EXIF
PENTAX K-5  Photo 
07-07-2012, 09:16 PM   #13
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QuoteOriginally posted by LeDave Quote
NZ Ross you probably have the best copy of the DA* 16-50 f/2.8 I've ever seen, however this type of copy could take a long time to acquire, as Fontan said he had 3 total copies of this lens. Plus mine wasn't even close to yours at f/2.8 at all. Looks like you got a real gem to keep for as long as the SDM keeps moving. Pentax REALLY has to do something about this lens, seems like every copy is not the same at all, some serious QC and manufacturing problems right here.
I agree. This copy seems very nice. Having said that, I think it still lacks in . . . . clarity (we call it nukeh in Japanese) that is so evident in 50-135. I just don't think that this is a very good lens overall. It is probably a focal length(s) that is difficult to pull off from optical formula standpoint. I acquired 50-135 first, and I was simply floored by it, and then I bought 16-50 next and had thorough disappointment(s). Incidentally, my 50-135 began to squeak like a chipmunk, and SDM stopped working. I just could not win no matter what. THen the K-5 fiasco . . . Actually, I better stop
07-08-2012, 01:09 AM   #14
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I think 24-70 f2.8 (35mm equiv) is an important zoom range for any DSLR system. To think that the DA* 16-50 performs below par and that Pentax not doing anything about it is pure, sad. Sure the 16-85 is in the road map, but it ain't f2.8 constant, the best it could do is f2.8 @ wide end and f4 at the tele-end.

I am moving on to m4/3 as Panasonic had just released a sublime 12-35 (24-70 in 35mm equiv) f2.8 weather sealed lens @ 305 gram. I will rejoin Pentax again when they update the 16-50 with faster and more reliable AF motor and better IQ, and of course better DSLR with smaller sensor size. Some may argue m4/3's f2.8 dof is equiv to f4 in APS-C, but what concerns me is not all about bokeh, but also the ability to shoot @ constant f2.8 with good sharpness and to achieve low ISO.

Bye bye Pentax, and hello M4/3....
07-08-2012, 01:43 AM   #15
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QuoteOriginally posted by lightbulb Quote
Bye bye Pentax, and hello M4/3....
All the best with M4/3, I hope you really enjoy it.

I am still enjoying my K-5 and lenses immensely, and having an optical finder, and a really responsive camera is a huge plus.

Regards,

Ross
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