[Richard Day]

I'm guessing it's a Tokina.

Hmmm. The Tokina even claims to have a special coating to repel "water or fingerprints."

It's sad that a flagship lens is actually, pretty much, not a Pentax save for a few bits on the outside. And, clearly this is something Pentax needs to address.

There're also a lot of lenses on the Tokina page that make me really wonder who's making them for Pentax - there's a 35mm f2.8 macro, a 12-24 f4 ultrawide, a 50-135...

Very depressing. Do Pentax still make any lenses? It seems a clear-cut case of dodgy outsourcing.

They just co-developed the formula. Two teams combining their knowledge and resources.
Then, each his own route, including construction. Pentax added SDM and kept the screw, Tokina got rid of the screw (at least the Nikon lens does not work on the non screw D40). Pentax added sealing.
And a star...
And a gold band...

My (fairly well founded ) belief is that Pentax actually make the element groups for the high grade lenses in Japan and suppy both Tokina and their own lens assembly factory in Vietnam with them. *

It may also be that Tokina make some elements or element groups for assembly by both parties as well - Who knows? I dont think anyone that really does, will/can disclose!

* P.S. I personally know someone that visited Pentax's optical manufacturing plant in Japan late last year. Yes, they still have one in Japan, they make the elements for some of their lenses there.

[selar]

Pentax added SDM and kept the screw, .

Which resulted in a lot of DA*16-50 being screwed....

[kyrios]

Which resulted in a lot of DA*16-50 being screwed....

That's absolutely not correct. DA* 50-135mm has both (SDM & screw drive) and it performs flawlessly. Everyone is extremely happy with their 50-135mm.

kyrios

[janneman]

That's absolutely not correct. DA* 50-135mm has both (SDM & screw drive) and it performs flawlessly. Everyone is extremely happy with their 50-135mm.

kyrios

Sorry to dissapoint you, SDM on my 50-135 stopped working....

[Canada_Rockies]

I'm using it on a K100D, so the DA* is run on the screwdrive not the HSM. Mine has actually been refurbished and recalibrated by Pentax.

There's the occasional non-focus problems, but this one is definitely a lot better than the other 4 I tried, each one in different stores/conferences. I'm still really happy with it and it's 98% of the time bang on (and if not, I adjust with the manual focus ring). Coupled with the Pentax flash, this lens shines.

I've noted some purple-fringing (CA) wide open, and the F2.8 is a bit soft (nothing like my DA and M primes. those things are pretty sharp wide open) but overall it's still a good lens that can take good pictures. I've learned to live with it's faults so far....I consider them part of the character of the lens. But that being said, there are a few copies of this lens that seriously need some work (as was the case of the first 4 that I tested... and didn't buy).

DxO's software cleans up CAs, PFs, vignetting and corner softness. $100. Check the sample on my Flickr site. It turned my expensive lens into one that cost another $100, but what a difference, and it is all automatic. No user input required except to select what you want it to fix and what you want it to leave alone.

[selar]

Which resulted in a lot of DA*16-50 being screwed....

That was more in the nature of a pun referring to the build issues of the 16-50, but I seem to have inadvertently opened another can of worms here.....

[aegisphan]

DxO's software cleans up CAs, PFs, vignetting and corner softness. $100. Check the sample on my Flickr site. It turned my expensive lens into one that cost another $100, but what a difference, and it is all automatic. No user input required except to select what you want it to fix and what you want it to leave alone.

Albert, besides the DA 16-50, is there any other Pentax lens in the DxO software?

[Canada_Rockies]

Albert, besides the DA 16-50, is there any other Pentax lens in the DxO software?

Yes, it covers both kit lenses (18-55 and 50-200) and the DA* 50-135. I should have mentioned that it does them on the K10D only. No doubt the K20 will be added when they finish testing, and other lenses. The corrections are done on a body/lens combination.

[aegisphan]

Thank you for the quick reply. I guess I will wait until they have the K20D profile. So far I'm really happy with my new DA* 16-50.

[kyrios]

Albert, besides the DA 16-50, is there any other Pentax lens in the DxO software?

DA 16-50mm.caf
DA 18-55mm.caf
DA 50-135mm.caf
DA 50-200mm.caf
DFA 50mm Macro.caf

That's all. But those modules will only work specifically for K10D.

kyrios

[VHDEL]

How far away was that chart? I could try some tests with similar sized text at the same distance to see what I get.

Thank's,

My fathers gone away on holiday for a week but I'll try to get around to his place
soon and get back to you with the chart distance/size and text size used.

Thank's (Blend 8) for the images, they do look very similar to what we're getting @ F2.8.

I would hate to think my father sending this lens back only realising that it was from the good batch & getting a lens thats far worse

Which was the reason for posting the images in the first place.

Once again, thank you for all your responces and for being so helpfull.

Cheers

[Tom M]

It just looks like normal edge sharpness fall-off to me. Stop it down some and see what you get.

[codiac2600]

Seriously though why do people insist on checking the extreme borders of this lens?

Look at the over $1000 Nikkor 17-55 f2.8 it has poop for corner sharpness yet it's still a stellar lens. If I grab the Tokina lens charts and compare them to the Nikkor the Tokina is sharper in the center and just as bad in borders and extreme borders.

I shoot the DA*16-50 and never run my lens through a shoot the wall test to see if the corners are good because corners don't matter.

Everyone forgets the simple math involved with lenses... if you have something goes extreme wide to semi telephoto you're going to gain edge softness and distortion because the lens has such a long zoom range. Which lenses are better than the 16-50 2.8.... well the canon 17-55 2.8 will do a better job at edge sharpness but it still isn't stellar there and the price tag of $999 from BH it better be good plus it has slight lens creep in some that i've seen and it had quality control issues for a little while.

Here is a DA*16-50 at f3.2


If you checked the image for border sharpness you aren't looking at the photograph properly.

Your best test for this lens is to shoot it IN THE ACTUAL ENVIRONMENT you are going to shoot it in.

[thePiRaTE!!]

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.

[JJJPhoto]

Seriously though why do people insist on checking the extreme borders of this lens?

Look at the over $1000 Nikkor 17-55 f2.8 it has poop for corner sharpness yet it's still a stellar lens. If I grab the Tokina lens charts and compare them to the Nikkor the Tokina is sharper in the center and just as bad in borders and extreme borders.

I shoot the DA*16-50 and never run my lens through a shoot the wall test to see if the corners are good because corners don't matter.

Your best test for this lens is to shoot it IN THE ACTUAL ENVIRONMENT you are going to shoot it in.

We might as well give up. I don't think it's possible to convince people that the 16-50 is a good lens if they've made up their minds that it's junk because it can't take photos of test charts as if it's a macro prime shooting at f8.

Seriously, if the only photos you create are pictures of test charts then the 16-50 is indeed not the best choice. Then again, if that's your criteria then most lenses won't be a very good choice.

Oh well, there's nothing really worth debating here. If someone thinks a lens is junk then it's junk (for them). If someone thinks a lens is great, then it's great (for them). We're talking about tools here. Use whatever works for you.