Posts Tagged ‘contrast’
At the beginning of the week, Canon introduced the latest and greatest addition to its APS-C lineup of DSLRs when it debuted the Canon EOS 70D. In addition to the standard specs you would expect to find in any of Canon’s APS-C cameras (the company has gotten some grief lately regarding its lack of innovation) the 70D packed one very impressive improvement.
The 20.2-megapixel Canon-designed sensor inside features something called “Dual Pixel CMOS AF”: a new autofocus system that promises to vastly improve the speed of Canon’s live view and video AF capabilities. And now, we get to see it in action. Read more…
Moscow-based photographer Alexander Khokhlov has a striking series of portraits of models with various designs painted onto their faces. The faces are either painted completely black or completely white, and then used as a canvas for some kind of artwork (e.g. a Mickey mouse face, a silhouette, a keyhole). Khokhlov calls the series Weird Beauty.
Contrast detection is one of the two main techniques used in camera autofocus systems. Although focusing speeds continue to improve, the method uses an inefficient “guess and check” method of figuring out a subject’s distance — it doesn’t initially know whether to move focus backward or forward. UT Austin vision researcher Johannes Burge wondered why the human eye is able to instantly focus without the tedious “focus hunting” done by AF systems. He and his advisor then developed a computer algorithm that’s able determine the exact amount of focus error by simply examining features in a scene.
His research paper, published earlier this month, offers proof that there is enough information in a static image to calculate whether the focus is too far or too close. Burge has already patented the technology, which he says could allow for cameras to focus in as little as 10 milliseconds.
One of the things you’ve likely seen when looking at product or review pages for lenses is an MTF chart, used by manufacturers to give consumers an idea of how sharp a particular lens is. If you’ve never gotten around to learning how to interpret these charts, here’s a helpful 10-minute video tutorial on the subject. Luminous Landscape and Cambridge in Colour have great tutorials on this as well if you’re more comfortable with text-based tutorials.