Andy Westlake tests Pentax's latest fully featured mid-range DSLR with in-body image stabilisation
Pentax K-70 – Features
With the addition of a 24.2-million-pixel APS-C sensor, the K-70’s pixel count is now on a par with its main rivals. In truth, the difference in resolution compared to the K-S2 is inconsequential, but there’s no underestimating its importance in marketing the camera to first-time buyers. With no optical low-pass filter, the K-S2 should match or exceed its competitors in terms of detail rendition, although with a greater risk of imaging artefacts such as aliasing, false colour and moiré. But like other Pentax cameras, the K-70 has a trick: it can use its in-body image-stabilisation system to eliminate these flaws by slightly blurring the image, emulating the role of a conventional anti-aliasing filter.
Indeed, it’s the in-body image stabilisation, along with its associated features, that really marks the K-70 out from the competition. The system brings some key advantages compared to Canon and Nikon, which both rely on in-lens stabilisation. It works with every lens you can fit onto the camera, including types that usually don’t include optical stabilisation, such as fast primes and wideangle zooms. It’s also capable of correcting for rotation around the lens axis, which can contribute significantly to image blurring during long exposures. However, in-body stabilisation is less effective when it comes to shooting with long telephotos, because the sensor movements required become ever more extreme. The viewfinder image isn’t stabilised, either, which can make composition more difficult.
The IS unit brings some extra useful features. First is Pixel Shift Resolution mode, which combines four exposures, made by moving the sensor by precisely one pixel between each. This allows the sampling of full-colour image information at each pixel location, which promises improved image quality. We’ll look into this later.
Second is horizon correction: because the IS mechanism can rotate the sensor, it can be set to ensure that the horizon is always kept level even if you hold the camera slightly askew, which can be handy for landscape shooting.
Third is Pentax’s Astrotracer function: in conjunction with the O-GPS1 GPS unit, the camera can move the sensor to keep track of star movements during long-exposure shots of the night sky. This is complemented by a newly added ‘night-vision’ LCD mode, that uses a low-contrast red display to avoid dazzling your eyes during night-time shooting.
Aside from all this cleverness, the K-70 offers a very solid core feature set. Its 11-point AF system includes nine cross-type points towards the centre, which are sensitive to both horizontal and vertical detail for greater accuracy. It’s capable of continuous shooting at six frames per second, which is faster than its main rivals. Its top shutter speed is likewise a little swifter, at 1/6000sec compared to 1/4000sec, which is handy if you want to freeze action or shoot with fast lenses in bright light. The sensitivity range covers a remarkably broad ISO 100-102,400, but as we’ll see later, the top settings aren’t great.
However, it’s when we look further that the K-70 really outshines its rivals. You get a whole array of features usually only found on more expensive models, such as in-camera raw conversion, autofocus micro-adjustment, and the ability to use the aperture ring on old Pentax K-mount lenses. Unlike the Nikon D5500, the K-70 can autofocus with older lenses that don’t have built-in AF motors. You also get a dual-axis electronic level to help keep your compositions straight, although only in live view: in the optical viewfinder, the exposure-compensation scale can be repurposed as a horizontal level.
Those interested in video will find that the K-70 can record in full HD at up to 30fps. Pulling the power switch beyond the ‘On’ position engages video mode, complete with the requisite 16:9 live view display, and there’s a 3.5mm stereo socket for using an external microphone. You can record in any exposure mode you want, including full manual. For video, the in-body IS is a bonus, but the lack of a touchscreen means that the K-70 can’t offer features such as touch pull-focus, or silent adjustment of camera settings.
As we’d expect these days, Wi-Fi is built in, allowing remote control of the camera from a smartphone or tablet with a decent level of manual control. You can also transfer images from the camera to your phone for sharing on social media. The
free Image Sync app is far from intuitive to set up and use, but once you’ve got the hang of it
the app works well enough.
If you prefer a conventional remote release, the K-70 is equipped with an infrared receiver for use with the Remote Control F. Its 3.5mm microphone socket also accepts the matched Cable Switch CS-310, or it can be used with older Pentax-compatible remote controls that have a 2.5mm plug via a simple adapter.