We shoot a specially designed chart in carefully controlled conditions and the resulting images are analysed using DXO Analyzer software to generate the data to produce the graphs below.
A high signal to noise ratio (SNR) indicates a cleaner and better quality image.
For more more details on how to interpret our test data, check out our full explanation of our noise and dynamic range tests.
JPEG signal to noise ratio
These results show that JPEG images from the Pentax K-5 II have a relatively strong signal to noise ratio when compared with the other cameras here. This means that the Pentax's JPEGs are consistently cleaner than those from the Canon EOS 7D throughout the sensitivity range. They beat the Sony Alpha a77 at all but ISO 400, and the Nikon D7100 at all but ISO 100, where results are almost identical.
Raw signal to noise ratio
TIFF images (after conversion from raw) from the Pentax K-5 II have the greatest signal to noise ratios of all the cameras here, beating the Nikon D7100, Canon EOS 7D and Sony Alpha a77 at every sensitivity setting. This means that the images are likely to be cleaner than those from the other cameras. TIFF images from the Sony a77 come closest to matching the scores from the Pentax K-5 II at the lower sensitivities.
JPEG dynamic range
JPEG results for dynamic range are again impressive, with the Pentax K-5 II's images showing a stronger dynamic range than those from the Canon EOS 7D at every sensitivity. They're also stronger than JPEGs from the Sony Alpha a77 at most sensitivities, but the two cameras show almost identical amounts of dynamic range at ISO 800, and the Sony's images beat the Pentax's at ISO 1600, before falling behind again afterwards. JPEGs from the Nikon D7100 have greater dynamic range than those from the Pentax at lower ISOs, but at ISO 1600 and above the Pentax's images overtake.
Raw dynamic range
As we can see from this chart, the Pentax K-5 II's TIFF images (after conversion from raw) show the strongest dynamic range of the group, beating the Canon EOS 7D and Sony Alpha a77 at every sensitivity setting. The Nikon D7100's TIFFs contain very similar levels of dynamic range as the Pentax's at ISO 100, but after that the Pentax takes the lead. A high dynamic range means that the Pentax K-5II is able to capture a wide range of tones in a single frame.