Originally posted by starbase218
Imagine the 17-70/4 would be similarly priced to the 16-50/2.8. Which one do you think would sell better, even with the increased range and lighter weight of the 17-70?
Not a fair comparison. The DA 17-70 is a nice lens, but it doesn't quite feature that Pentax limited or star rendering, microcontrast, or color rendition. Also, however expensive the DA 20-40 may be, it's not as expensive as the DA* 16-50. You will be saving hundreds of dollars going for the slower option.
If you're a landscape shooter and you want a WR standard zoom lens, until this limited zoom, you had three choices for K-Mount: the DA* 16-50, the DA 18-135, and the DA 18-55 WR. If you wanted the very best standard zoom lens for landscape, your only choice was a lens that was heavy, that was prone to SDM failures, and that forced you to pay extra for speed you didn't need. With the DA 20-40, we now have a high end WR standard zoom that's a better fit for landscape shooters than anything else offered for APS-C DSLRs,
regardless of brand.
Why do the fast lens-ophiles have to complain that finally those of us who prefer slower glass now have
one high-end standard zoom lens to fit our needs? Does every lens Pentax makes have to fit your specific needs? After all, their are plenty of fast zoom lenses to choose from. Not only the 16-50, but multiple options from Tamron and Sigma. Sigma even has a 1.8 zoom, which will appear in the K-Mount early next year. Camera manufacturers tend to cripple their slower zoom lenses by using inferior glass, coatings, build quality in order to save money and force march their high-end users into buying more expensive, faster lenses, regardless of actual need. There is actually a greater need, and hence potentially a greater demand, for slower high-end glass, because there's so much less of it out there.
When Canon in 1999 released their 70-200/4, that lens became an instant classic among landscape photographers, and remains one of the most highly regarded zoom lenses for landscape photography to this day. But for years that Canon 70-200/4 was more the exception than the rule. Nikon didn't get around to make a 70-200/4 until last year. Although both companies makes some nice prosumer f4 zooms, if you want the very best Nikon or Canon WA or standard zooms, you've got splurge for the f2.8 variants. When I go on trips throughout the American West, I see scores of landscape photographers toting immense Canon and Nikon FF cameras sporting immense f2.8 zooms. It doesn't have to be this way. There's no reason why a variable aperture zoom or constant f4 zoom can't be every bit as good, both in terms of optics and build quality, as the f2.8 zooms. Nikon and Canon have avoided making such zooms in order to force their users into paying for wide apertures that are largely useless to the landscape photographer.
Pentax has provided some great zoom options for landscape photographers on the wide and long end of things with the DA 12-24 and the DA* 60-250. But in the middle Pentax users have been forced to choose between one high-end f2.8 zoom (with SDM problems) and several mid-range offerings. Until now. I can see the DA 20-40 being the same sort of game changer for Pentax landscape photogs as that Canon 7-200/4 has been for Canon landscape photogs.