Probably the Mark II’s most intriguing feature is its handheld pixel-shift mode. This is enabled by setting Pixel Shift Resolution function to ‘Image Stabilisation On’. The camera will then take four exposures and align them to produce a composite file.
It’s clear from the outset that this mode isn’t doing the same thing as conventional pixel-shift. For a start, the camera uses the mechanical (rather than electronic) shutter to shoot the four frames, in noticeably quicker succession. But it then spends an inordinate amount of time aligning the exposures and processing the file, locking you out from taking another picture for 30 seconds or more. As with conventional pixel-shift you end up with a raw file that’s typically 170MB, compared to 45MB for a single shot, meaning it contains the data from all four exposures. As yet, though, Adobe Camera Raw doesn’t understand how to process it to anything more than a conventional image from the first frame.
In handheld mode, the camera clearly isn’t full- colour sampling each pixel. Instead, it’s aligning and averaging four conventional image files. But because of the slight differences between each handheld shot, in principle it’s able to extract more detail overall. In practice, the sharpness improvement is much less clear- cut compared to the tripod-based pixel-shift modes, although with favourable subjects, it’s definitely visible. But I’m not convinced it’s significant enough to justify the inconvenience.
Conventional pixel-shift, meanwhile, behaves much the same as on previous Pentax DSLRs. It gives stunning results with static elements, revealing visibly higher detail and colour gradation. However, it’s essential to engage motion correction whenever part of the scene may be moving (which in practice means anything shot outdoors), as otherwise you’ll get ugly artefacts that offset any advantage of the extra resolution.