[sinus007]

Anyways, I now officially love the DA*16-50, even with a bit of the sticking.

Who is the official? And it's not in your signature?

Just kidding

[TanGU]

No problems here. When I used the 16-50 on the K10D, I was shocked by some terrible CA if exposure was off. Since then on the K20D, I haven't noticed it, so I think the camera body has an impact.

However, I have taken a few shots on my K20D with the DA*200 that also showed some terrible PF (and I mean fluorescent PF, just horrible). So the K20D isn't immune to PF.

I have a K10D and i want the 16-50 da* too...

What do you mean that terrible CA if exposure was off?? Is it a setting or only a picture with less explosure than needed??

[wiyum]

Hey everyone,

I'm just trying to figure out what aberrations are "normal" for a *good* 16-50 and what might be indicating a problem. I've just shot a long series of shots at all marked lengths (16, 20, 28, 35, and 50) at 2.8, 5.6, and 11 at three different distances. I'm not posting any pictures (yet) because it'd be alot to do and no one wants to look at 45 images of newsprint. But...

My lens seems to be pretty terrible at 28mm. At 50, I've got decent results even at 2.8. At 16, things are fuzzy in the corners at 2.8, but at 5.6, they look pretty OK. But at 28mm, the corners are a mess at 2.8 and not much better at 5.6. At 20 and at 35, things are as you'd expect, somewhere between the madness of 28mm and the acceptable results of 16 or 50.

"Centering" seems to be fine with the lens, in terms of corners being very similar from corner to corner within a single image. The top right, bottom right, top left, and bottom left corners are equally good and equally bad in each image.

I should add that the center of every image is crystal clear.

So back to the original question: what can I reasonably expect? I'm not wild about what I'm seeing in the corners here at 28mm at most apertures and closer focusing distances. But if that's normal, I guess I'll live with it. If that isn't normal, I need to get in touch with Pentax!

Thanks in advance to everyone that can offer any advice. And I'll be glad to provide examples if anyone cares to look.

Will

[cupic]

A good bang for your buck lenses


cheers

[k100d]

sounds like you got a bad sample, but it'd be better to see photos. perhaps there is a focusing issue as well?

have you looked at the DA* 16-50 thread that's been stickied as well?

[Serpiente]

mmm I want this lense, but all those issues I begin to doubt!

[PentaxPoke]

Hi again folks. Well some here may have read my thread some time ago about how a new DA*16-50 I bought was decentered. In other words, in all the pictures, the right side of the image was out of focus. I sent that one back to Amazon and got a full refund.

So I waited a couple of months, and decided to give the 16-50 another chance. This time I bought a new one from B&H. I received it less than a week ago, and started snapping away like mad. To my dismay, now it wasn't just the right side out of focus, the left side was out of focus as well! The center was very sharp. Wishfully thinking to myself, I thought "maybe this is just because I am taking shots at f/2.8 and it is soft around the edges." Well, to my further dismay, the softness happened at all apertures and all focal lengths! This is not "pixel peeping" either. You can see the problem even without looking at 100% crops! The center was very sharp but as you move towards the edges it is very noticeable. It is not my camera either because none of my other lenses listed in my signature had this problem. For example, the sharpness of my 18-250 at the edges in comparison, made the 16-50 look like I was taking pictures through a Coke bottle (I exaggerate).

Luckily, B&H has a great return policy, and they pay for shipping. I am giving this one more chance: if the 16-50 I get back this third time is defective, I must end this quest.

[hinckc]

Hi PentaxPoke,

Too bad you've had to go through all that.

One thing I was thinking as you described your new (well, 2nd) lens was that maybe the AF was front or back focusing. That would yield a completely OOF shot like you described.

Was it any better or worse with your K20 than your K10? Did you try MF?

I sure love mine. I've used it on my K100D, K10D, and K20D, with success across the board.
But I never did one of these tests that everyone does. I really need to try a brick wall to see what mine delivers....

Best of luck!

-Chris

[NaClH2O]

Sorry to hear about your woes PP, but you've got my admiration for patience and tenacity! After two bad copies of the much ballyhooed FA* 24mm I gave up. It's stories like yours that keeps me away from this lens. I can however recommend the Sigma 17-70. It's not weather sealed and doesn't have SDM, on the other hand it also doesn't have decentered or other QA issues.

NaCl(but the third's the charm, so they say)H2O

[Serpiente]

is Pentax working on it? I think their testing isnt optimal

[PentaxPoke]

Chris,

I don't think it was FF or BF. The center of the images were always very sharp. I have no complaints about focus speed or accuracy on the lens. I would just like to get one that actually can focus across the entire field of view!

Here is an example of how bad it is. I am saving bandwidth on this site, so trust me that both pictures are very sharp in the center. These are just crops of the edge of the frame. In the Tamron 17-50 shot, it is at the absolute edge. In the DA*16-50 shot, the crop is not even to the edge of the frame! (Can you guess which one is the DA*?)

[PentaxPoke]

Will,
How do your images compare to the ones I posted here:
https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/34507-my-da-16...hapter-ii.html

I compared my (second) DA*16-50 to my Tamron 17-50 as well as my 18-250 (not shown). Not only was the lens worse than the other two, it was worse than a P&S camera I used to take the same picture! The center of each image was very sharp, but the edges were terrible at all focal lengths and apertures I tested. Needless to say, I sent the lens back, and I will be on my third one...

[hinckc]

Hi PentaxPoke,

Sadly, I see what you mean -- Guessing the 16-50 was on the right... It's not even just OOF, it looks stretched or "nervous"....

Just trying to cover all the bases....

It's just that..... I tried 2. One at my local shop, and one at B&H, and both were beautiful.... It's not that I don't believe so many are bad, it's just that I have a hard time believing it. I'm just glad I'm as lucky as I am!!!

I really hope that 3 is a charm for you, as Salty said...

I'll try to get a shot of the "wall" before the weekend's here... At least so there's a comparison...

-Chris

[wiyum]

Poke,

Wow. Nowhere near as bad as that. See, this has me wondering if I'm being paranoid or not. I've never purchased a lens that had QC problems before, so I've never felt the need to shoot a newspaper test before. The whole affair has me wondering if what I see in the corners is normal for such a complex zoom or not.

Then I look at my pictures again. While I can certainly say that I don't have the problems you had, I can also say that what I'm seeing in the corners at 28mm/2.8 is really, really bad.

Will

[Substitute]

Just because I am sort of tired of posts with crappy test shots, here is what you can really expect of your DA 16-50mm

All you need is Sebastian MySpace.com - SebastiAn - FR - www.myspace.com/0sebastian0 on stage
3000 rocking kids
a K20D set at 800 iso 1/8 s and your 16-50mm at 2.8.
No Lightroom tricks of any kind.

Press button and:



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