[Newtophotos]

I know the Sigma lens has a lower f-value so the low-light performance will be much better but can we expect equal or better IQ in the center for the Sigma as compared to the Pentax?

[DSims]

I hate to say it, because I'm a fan (and owner) of the DA*16-50, and I don't like Sigma as much - but yes, it probably will. That is, provided you like the way Sigma renders images.


Sigma rendering is usually a deal-breaker for me - I just can't enjoy the lens enough because of it. But if that doesn't bother you, I'd find it awfully hard to believe the DA*16-50 would give you better results within that range. I'm still happier with the DA*16-50 compared to any of the alternatives, and it renders a look similar to what I want. But it's really not that strong a lens if you're being picky or trying to use it wide-open, so a well-designed Sigma f/1.8 zoom should easily better it (especially when it's a brand new design from the much-improved Sigma of the last few years).

[Adam]

I know the Sigma lens has a lower f-value so the low-light performance will be much better but can we expect equal or better IQ in the center for the Sigma as compared to the Pentax?

Assuming the it actually comes out, the answers is probably yes since the Sigma is designed as a wide zoom rather than a walkaround lens. There are plenty of reviews & tests already out there for other mounts, and the lens has enjoyed great popularity for its IQ

[Newtophotos]

I hate to say it, because I'm a fan (and owner) of the DA*16-50, and I don't like Sigma as much - but yes, it probably will. That is, provided you like the way Sigma renders images.


Sigma rendering is usually a deal-breaker for me - I just can't enjoy the lens enough because of it. But if that doesn't bother you, I'd find it awfully hard to believe the DA*16-50 would give you better results within that range. I'm still happier with the DA*16-50 compared to any of the alternatives, and it renders a look similar to what I want. But it's really not that strong a lens if you're being picky or trying to use it wide-open, so a well-designed Sigma f/1.8 zoom should easily better it (especially when it's a brand new design from the much-improved Sigma of the last few years).

Thank you both for the replies. I'm still new to this (as my name implies), do you mind explaining further what you mean by rendering and how they both differ in this area?

[DSims]

Thank you both for the replies. I'm still new to this (as my name implies), do you mind explaining further what you mean by rendering and how they both differ in this area?

We use the term 'rendering' because it's a little hard to describe, and that term can encompass many different characteristics in an image. But in the end it means the overall look or appearance of an image. One of the characteristics I'll notice in virtually all Sigma lenses is the colors look different compared to most Pentax or Tokina lenses - or any other brand's, for that matter. To me the Sigma colors look saturated - but like the artificial colors on a candy cane - whereas the Pentax lenses with saturated colors look more natural or pleasing to me. So I (and a sizable minority of other members here) don't like it as much. But admittedly this lens' images don't seem to look as much "like a Sigma" as some of their other lenses. Either way, it's a matter of personal preference.


When I was building my lens kit (and making substantial investments in lenses) I would look at the images from potential lenses quite critically, and I could often identify an image from a Sigma lens right away - even if I'd been given no hint it might be a Sigma. So the difference can be seen. And IMO this affects how someone responds to an image subconsciously. But if you're not trying to pay attention you won't notice consciously, most of the time. It's just that I figure as long as I'm spending the money and putting in the time, I may as well have the lenses, the camera, and the Post Processing software I prefer - all of these can add up to an end product that's just a little bit better than what the average shooter may get.


So you just need to look at photos produced by the different lenses and see what you like. I don't think you even need to understand technically "what you're supposed to look for;" just go with what captures your attention - what you like. If one lens has 3 or 5 images that really strike you, and the other has none (or maybe just 1), it's usually more than coincidence, and you know which lens you should get (when you can afford it). Of course you want to look at over a hundred images from each lens, when possible. You can search on the internet for them, but my favorite 3 places to look for images from specific lenses are:

PENTAX : Select a PENTAX interchangeable lens camera or a lens model
PENTAX : Select a PENTAX interchangeable lens camera or a lens model

Sigma 18-35mm F1.8 DC HSM Art lens Lens Sample Photos and Specifications
Pentax smc P-DA* 16-50mm f/2.8 ED AL (IF) SDM Lens Sample Photos and Specifications

Full-size sample photos from Sigma 18-35mm F/1.8
Full-size sample photos from Pentax 16-50mm F/2.8


Different cameras will give a slightly different look, and you'll learn to recognize the differences over time, but for the most part what you see is a result of the lens and not the specific camera used.

[Driline]

Not ever owning a Sigma myself, I've read other posters who have described the Sigma rendering of colors as more yellowish looking or akin to shooting through a glass of urine. A rather harsh statement, but the pictures I have seen taken by some Sigma lenses does in fact look a bit yellowish to my eyes anyway.

[RobA_Oz]

Having owned the DA*16-50 and two Sigma zooms (the 10-30/3.5 and the 8-16) I can't say the reports of odd colouring have been borne out for the Sigmas, any more than the reports of poor IQ for the DA, in my experience. In all cases, being short FL zooms, expectations of sharpness and distortion over the various ranges shouldn't be excessively high, as they're all optical compromises, compared with primes. I've used my DA*16-50 on four Pentax DSLRs now, and I really feel the K-3 brings out the best in it. Maybe the same will go for the new Sigma. I expect it will be good – Sigma's design and quality management have improved greatly in recent years – but given the aperture and my experience with its earlier stablemates I also expect it to be quite heavy.

[Rondec]

I think I would say that if you are doing indoor photography, the Sigma 18-35 would be a better choice. Looks pretty sharp wide open. A stop faster and wide enough for all normal purposes.

On the other hand, if you are more of a landscape photographer, the 16-50 is fast enough, weather sealed, probably a little smaller, with a little wider range. I'm pretty happy with my 16-50 and for landscapes.

The biggest weakness for both of these lenses is going to be flare resistance. When you have that much glass between you and the sun, even with great coatings, flare can and is an issue.

(16-50 shot).

[Dice]

I do not know the answer to your question but I will share what I experienced, what I've seen from images and my conclusion based on those two things which may not be worth the time it took to right this. If you like to shoot wide open, I can say from experience that my copy (which I no longer have) of the DA* did not produce the edge to edge and corner to corner sharpness that the full size images coming out of the Sigma appears to deliver. My copy required stopping down to get the type of corner to corner that I'm seeing from the Sigma. From the images that I carefully looked at, the sigma is very sharp wide open and then only gets marginally better stopped down (not that is a bad thing as it is very sharp wide open). My copy of the DA* had more fringing than the images that I'm seeing from the Sigma. Both do not do a good job at controlling flare.

In the right hands (as you see Rondec's work above), the DA* produces great color and contrast and from the images I've seen from the Sigma it does an equal job. Bokeh is such a personal thing that I don't really want to comment here.

So in conclusion both lenses have their weaknesses. Sample variation in my experience with the DA* is something to consider. I went through several copies of the DA*. I don't know about the Sigma though if you read reviews, it appears to be loved universally. As a landscape lens I think both do a good job. But since I haven't shot them side by side I can't say with certainty 1 is better than the other. You can coax excellent images out of the DA*

[gdourado]

Does the Sigma have any kind of weather sealing? That might be the deal breaker. More than IQ...

[Simen1]

No, it doesent, so i keep an 18-55mm WR for the rainy days.

I hear theese lenses are starting to ship now. I'm so looking forward to get mine.

[robjmitchell]

While the yellow sigma tint was obvious in my 17-70 i could not pick up up when I had the Sigma 70 macro (probably equivalent to art series). Along with their optical improvements of late they have probably improved the coatings as well.

[ChristianRock]

A 2x zoom is inherently better (or at least sharper) than a 3x zoom. The 16-50 isn't bad for what it is and it can crank out some great pictures. But it might be time for an update...

[zeitlos]

I'd say, incredibly good image quality... see for yourself

Sigma 18-35 / 1.8 DC auch für Pentax?! • Pentaxians