For its latest top-of-the-line SLR, the K-3, Pentax overhauls the K-5 II and IIs models inside and out: it's got a new sensor, new body design, new AF system, new metering system, and improved performance.
Like these earlier cameras (and the Nikon D7100), the K-3's new 24-megapixel sensor drops the optical low-pass filter (OLPF) entirely. But sometimes you want the slight blurring effect of the OLPF, especially if you know moire will be a problem — and Pentax takes a novel approach to addressing that concern. The K-3 can use its sensor-shift shake reduction mechanism to slightly offset the pixels with circular, horizontal, or vertical movements. It doesn't seem to be available in movie mode, however. To compensate for the increased vulnerability of the sensor, there's now a vibrating piece of coated glass over it for dust protection and removal.
The new autofocus system unfortunately doesn't have any Live View optimisations, though Pentax says that five of the AF sensors are specifically for low light, and even the pre-production model was able to lock focus in some pretty dim conditions. Pentax also takes a leaf out of Nikon's and Canon's book, implementing a more granular, RGB metering system and using the data from the light meter to supplement the autofocus. Like the Canon EOS 70D, it now implements Zone Focus, though it doesn't display the zone — just the selected focus point — on prefocus. It does seem to select the centre of the zone more often then not (which is good). The camera retains the expanded area AF as well.
Per Pentax, the new viewfinder has improved coatings on the prism for better refraction and reflection for sharper image, with slightly increased magnification, and while we don't see a perceptible difference it's still a nice viewfinder. It's also the first camera to support USB 3.0. We're not quite sure of the implications yet, as that depends on implementation, but it does open the door for faster download speeds to the computer and improved bandwidth for tethered shooting.
Performance enhancements include a boost to 8.3fps continuous shooting with a usefully deeper raw buffer, which in ostensibly puts the K-3 ahead of its class. It also potentially delivers improved image stabilisation (an extra stop) and better shutter durability. Pentax brings its movie mode into parity with the rest of the world with 1080/30p and 720/60p options, along with a mic and headphone jack, and it now has peaking for manual focus. There's also a new 4K (3840x2160) option for interval shooting. Filters now work in RAW+JPEG and movie modes.
The body design, while not completely overhauled, does have many significant changes over the K-5 series. The mode dial is now lockable; there's a lock switch that you use in conjunction with the more typical central button. Pentax has also adopted the convention of a switch for toggling between movie and still capture, with a dedicated Live View/Record button.
The new navigation buttons are cleverly designed for moving diagonally (as you'd want to do when selecting focus points).
There are some disappointments, though. For one, it's got a fixed rather than articulating LCD; oddly, Pentax is the one manufacturer that resists incorporating movable LCDs. Flash junkies will notice it still has a pretty slow sync speed. And it lacks built-in Wi-Fi, instead opting for SD-card-based solutions, though there will be a custom Pentax Flucard option to support wireless tethering options via web browser.
The K-3 will be available in Australia from 1 November for AU$1599 with an 18-55mm lens or an 18-135mm lens for AU$1799.