<p>Back in late 2012, Pentax introduced a new multi-layer lens coating dubbed HD, for "High Definition". According to its maker, the HD coating offered a couple of key benefits, but it's not until recently that we've been able to make a real-world comparison to test these claims. We've now done so, and the results are rather interesting.</p><p>When it launched the HD coating, Pentax promised that it would be more durable, yield better color balance and better control reflections, a key to reducing lens flare. The company predicted a better than 50% reduction in reflections across the entire visible spectrum, so we were led to expect a pretty significant improvement -- but at the time there was no way to make a direct comparison against a non-HD coated lens. More recently, though, Pentax has also updated its entire DA Limited lens lineup with the new HD coating, and as it happens, I own a couple of the original, non-HD versions of the same lenses. A comparison was clearly in order, then.</p><p>Shortly before departing on vacation to Hong Kong, I tried a few different tests, shooting my own non-HD glass side-by-side with the new HD variants using our review sample of the Pentax K-3 body. First of all, I shot some images right near sunset in downtown Knoxville, Tennessee, intentionally provoking lens flare by keeping the sun fairly close to the image frame. I also took some shots of nearby brick buildings with a vast array of rooftop airconditioners, providing lots of fine detail. And then I took camera and lenses back home for some bokeh testing, given that the newer lenses are also said to have rounder aperture blades.</p><p>Pentax's overhauled DA Limited lineup includes a 20-40mm f/2.8-4 lens, the first in the family to feature either weather-sealing or an optical zoom.</p><p><a href="http://www.imaging-resource.com/news/2014/03/19/farewell-to-flare-pentaxs-hd-limited-lens-lineup-gets-a-real-world-test">Keep reading...</a></p>