Originally posted by David&karen The title says it all. Points go to the one(or many) who have the older DA model and compare. I am esp. looking at focusing speed with the new lens and if the optics are any better with the HD coating. Thanks,
David
I don't have a k3 but did make several hundred direct comparison images between the WR and DA, on a K5 and K200. All were tripod-mounted (3028, so a non-trivial tripod) and fairly well controlled, using a mix of lv focus, autofocus, test targets and actual scenes, etc. Some were intentionally made with backlighting. Statistically, the DA focused slightly faster (as in the same, except a couple of extra hunts on on the WR, which of course throws off its average.) So I'd say focusing was really a tie. I couldn't tell a difference in the coatings, but would ascribe that to testing limitations and trust Pentax that the new coating is better (I didn't try rubbing until the coating came off, for example - no destructive testing here.) There were obvious differences in the resolution of the images, which I compared side-by-side at 100% on my admittedly low-res monitor. I made notes at each of the several focal lengths, apertures, and focusing distances I tested at.
My notes on the first copy of the WR and my old DA looked like "DA wins lower left, WR wins right side, rest tie." But they were different for almost every picture; that was just an example. When I added things up the DA was marginally better on average, so I kept it. But it was close; sort of 60/40. Where the WR underperformed in a few cases it underperformed a little than the DA so maybe it was more like 45/55 but I gave the DA more points for being closer. My DA always had tended to be weak in the upper right at 200+ (beaten out by my 100-300F - the 4.5-5.6 version) and that generally held true in these tests, but the problem was that neither the DA nor the WR was consistent. It was almost like the elements weren't firmly attached, although there was no physical indication of that. In one test I'd get different results from another at roughly the same focal length and aperture.
I would have been ok with either lens, or at least equally unhappy with either one. For important pictures with that lens now, I always take several images, and either refocus myself or let the lens refocus between them, etc., and then just hope for the best. Almost all my pictures with this lens are f11, f13, f16, and that definitely does help even things out. You might not get the optimal resolution at 300mm and f16 but what you lose is more than made up for by consistency across the frame, partly because at 300mm there's not much dof. Obviously this only applies to something that works best with corner-to-corner sharpness. Typical wildlife, portraits, flowers, etc. aren't issues. Both lenses were pretty consistently good in the center, even wide open.
Then came the 2nd WR. No surprises there. It was broken below 100mm in the lower left and nothing would fix that (tried lv focus on the lower left, etc.) It took me about ten seconds to find that and determine it wasn't for me, although I went on to test it with another hundred or so images. It was a 100% consistent failure in the lower left at 70-100mm, but the same as the other two everywhere else.