Sigma 17-50mm F2.8 EX DC HSM or Pentax DA 16-85mm F3.5 - 5.6?

awaldram wrote:

audiobomber wrote:

Again, not true according to my usage, nor the reviews. Where are you getting your information?

My opinions expressed are as always based on my personal experience

Yes, and from previous discussions, I know that your opinions trump the facts.

The opinion I expressed were based predominately in a fiends 17-50 on a Canon Vs my experiences with Sigma 18-50, Pentax 16-50 and many more standard zooms

So not professional reviews.

But your comment made me think maybe its a single variant and the norm is better than I paint.

So I went to the first review site I know that has proper testing rather than opinion.

And the graphs tables and reports clearly back up my option rather than yours.

http://slrgear.com/reviews/showproduct.php/product/1329/cat/31

The Sigma 17-50mm is a zoom. It has some weaknesses vs. primes, but it's clearly in the forefront of standard zooms, as shown in the SLR review, where it stands up to the best from the OEM offerings.

Mind you the other lens you mention with glowing reports the 16-45 is also not one I'd consider decent with it very poor build and abysmal correction it is in my mind a very poor lens, the current and indeed Mk1 kit 18-55 are clearly better @f5.6 or greater.

The 16-45mm is a superior lens to the 18-55. That is easily provable. Its only flaw is higher than normal CA, which is easily corrected with one click in Lightroom.

On flare a quick google of 17-50 flare brings up a plethora of examples of Sigma poor performance

http://www.dpreview.com/forums/post/38103177

"I sent mine back to B&H after an hour of testing. I was very surprise by the amount of flare"

Some Guy On The Internet, what a reliable source.

or lenstip http://www.lenstip.com/256.9-Lens_review-Sigma_17-50_mm_f_2.8_EX_DC_OS_HSM_Ghosting_and_flares.html

"The Sigma 17–50 mm f/2.8 has some issues with the work against bright light but fortunately they are not huge. You can catch light artifacts the easiest at the shortest focal length and their intensity increases after the stopping down of the lens"

Every zoom has flaws. It's easy to pick on some area where it is imperfect, they all have them. Here's the big picture:

LensTip conclusion: Reading our test you can see very clearly that the Sigma entered the segment of more expensive fast zoom lenses, aimed at ambitious amateur photographers or even professionals working with smaller sensors, very aggressively indeed. The performance of the tested lens is sometimes really impressive. In the frame centre the Sigma behaves better than more expensive constructions of Canon and Nikon. At the edge it is worse than the Nikkor but it can compete on equal terms with the Canon. In fact it doesn’t lag behind the competitors in any category and in some it fares definitely better.

http://www.lenstip.com/256.11-Lens_review-Sigma_17-50_mm_f_2.8_EX_DC_OS_HSM_Summary.html

Photozone: The Sigma AF 17-50mm f/2.8 EX DC HSM OS is a highly competitive APS-C standard zoom lens and Sigma's best product in this class so far. It's not a flawless lens, though, but none really is.

Score: 3.5 stars for the Sigma vs. 3 stars for the DA*16-50

http://www.photozone.de/nikon--nikkor-aps-c-lens-tests/838-sigma175028os?start=2

DXMark: Sigma’s high-grade models continue to perform well with the constant aperture ultrasonic focusing 17-50mm f2.8 EX DC HSM sitting in the top slot out of those tested, and that includes Pentax’s DA* 16-50mm f2.8 and the more modest DA 16-45mm f4, albeit those models coming in second and third place respectively. The Sigma has the highest measured peak sharpness and it’s the best corrected of the 14 models in our database tested on the K-3.

http://www.dxomark.com/Reviews/Best-lenses-for-the-24-MPix-Pentax-K-3-Recommended-primes-and-zooms/Best-zoom-lenses-for-the-Pentax-K-3

Pentax Forums In-Depth Review, DA*16-50 vs. Sigma and Tamron 17-50 Comparison:

• DA*16-50 score 7.6, ambitious but flawed
• Sigma 17-50 score 8.0, simply solid
• Tamron 17-50 score 7.7, a superb value

http://www.pentaxforums.com/reviews/pentax-16-50-vs-sigma-tamron-17-50mm/conclusion-summary.html#ixzz3vAnd6kuZ

Pentax Forums User database, 27 reviews, score 9.04/10.

http://www.pentaxforums.com/userreviews/sigma-17-50mm-f2-8-ex-dc-os-hsm-no-stabilizer.html

Getting back to the OP, the Sigma 17-50mm has higher IQ and a faster aperture than the DA 16-85mm. The Pentax has WR and extended range in its favour. Each person has to weigh these differences based on personal preferences and their personal lens plan.