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 images from the Canon EOS 7D compare reasonably well against the newer 24.3 million pixel Sony Alpha 77, and whilst at the lower end of the sensitivity scale the 12.3 million pixel Nikon D300s has the edge, at sensitivities above ISO 800 the Canon EOS 7D shows better low light performance.
This chart indicates that the Canon EOS 7D's JPEGs capture a good amount of tonal detail across the sensitivity range, beating the Nikon D300s at all sensitivities except ISO 800. However, it is out performed by the Sony Alpha 77 and Pentax K-5.
TIFF images (after conversion from raw) show a similar trend to the JPEG files with results showing a higher dynamic range than the Nikon D300s at all sensitivities except ISO 800. Again, it is out performed by the Sony Alpha 77 and Pentax K-5 though.