The Pentax KP is loaded with features, but does it do enough to stand out from the big guns in the enthusiast DSLR market? Michael Topham put it through its paces
Pentax KP review – Dynamic range, resolution & noise
Our lab tests tell us the KP resolves the level of detail we’d expect from a 24-million-pixel sensor without an optical aliasing filter and you can confidently use the camera at up to ISO 6400 without too much concern. You’d get away with pushing to ISO 25,600 in an emergency, but the headline-grabbing ISO 819,200 should be steered well clear of. Raw shooters will appreciate that it records in Adobe’s DNG format, which means that unlike other new models, you shouldn’t need to update your software to handle its files.
At ISO 100, the KP’s dynamic range result measures 12.7EV – a figure that’s higher than the 12.3EV we previously recorded on the Pentax K-70, but not quite as high as the Pentax K-1 that records 13.8EV at the same sensitivity. It manages to stay above 12EV until ISO 800, after which it drops down to a still respectable 11.4EV at ISO 1600. Results at ISO 3200, 6400 and 12,800 drop to 10.4EV, 9.3EV and 8.1EV respectively, with shadowed areas gradually getting noisier as you push towards ISO 25,600. It’s highly impressive to see the KP recording figures above 6EV right up to ISO 51,200.
The results above show the level of detail the KP resolves by shooting in raw with the pixel-shift resolution mode and AA Filter Simulator switched off. The sensor can resolve 3,600l/ph at ISO 100 just like the Pentax K-70, but traces of moiré and false colour are suppressed heavily by JPEG processing, leading to a noticeable drop in resolution. To resolve the finest detail, shooting in the raw format is imperative. Push past ISO 25,600 and the detail deteriorates quickly, with the highest settings being too poor to be worth illustrating here.
Both raw and JPEG images taken from our diorama scene are captured at the full range of ISO settings. The camera is placed in its default setting for JPEG images. Raw images are sharpened and noise reduction applied, to strike the best balance between resolution and noise.
At low ISO sensitivities, the KP’s image quality is excellent; fine detail is rendered in its raw files thanks to the lack of an optical low-pass filter, and there’s no visible noise between ISO 100 and 800. Luminance noise does start to appear at ISO 1600 but it’s by no means detrimental and you can create usable results at ISO 3200 and ISO 6400 by applying a little noise reduction. If a shooting situation forces you to go higher than ISO 6400, pushing the KP to ISO 25,600 isn’t out of the question but should be seen as the upper limit you’ll want to push it to in an emergency. Saturation takes a hit at ISO 51,200. At ISO 204,800 you can just about make out the outlines of a subject but at ISO 409,600 images suffer so severely from noise you’re not quite sure what you’re looking at.