One significant change compared to the Pentax K-x is the newly expanded K-r ISO range. With a slight adjustment to the custom settings menu you can set the ISO as high as 25,600. That's twice as sensitive as the Pentax K-x and Canon 550D, and four times that of the Nikon D5000.
So what can you do with it? We're pleased to report that below ISO 1600 you won't really need to worry about your images – our tests came back virtually indistinguishable from each other. You can even set up the Pentax K-r to prevent it reaching for undesirable ISOs: set the maximum at ISO 1600 and we doubt you'll ever have a serious problem with noise.
The higher you go the softer images become. At ISO 3200 noise is still fairly well controlled, and the Pentax K-r samples we took provided commandingly accurate colours – sharpness appeared to be the only casualty.
Go a stop further and you'll begin to hit problems, though. ISO 3200 provided us with an image in which smooth textures had been replaced by mottled JPEG compression, and sharpness was all but gone. Go further still and colours begin to shift badly – the final two stops are best avoided unless you're presented with a once in a lifetime opportunity.
The SMC DAL 18-55mm f/3.5-5.6 AL Pentax K-r kit lens is another treat: it's light weight and, while its specifications are run of the mill, like the kit lens on the Pentax K-x, it's pretty sharp and chromatic aberration is kept to the barest of minimums. Our only complaint is the audible noise: the Pentax K-r's in-body focus motor sounds decidedly old-school and will definitely prick up the ears of any quietly grazing wildlife.
Our review unit came as a package with an SMC DA 50mm-200mm F4-5.6 ED lens as well, with which we were less impressed. When it was mounted the K-r had a little trouble picking out fine details in our test shots, and although the Pentax K-r image sensor shifting Shake Reduction (SR) is built-in, we struggled to get sharp images at 1/60sec when using the 50-200mm lens at its longest point, our video tests were particularly badly affected by shake. Take a tripod!