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
The Alpha 7S has the highest signal to noise ratio at its lowest and highest sensitivty settings, indicating that its images are cleaner than those from competing cameras - including the Nikon D4S.
Raw (after conversion to TIFF) signal to noise ratio
Although the Panasonic GH4 leads the way for the majority of its sensitivity range this doesn't extend as far ast the A7S's. At the very highest settings the A7S beats the Nikon D4S, but it's a pretty close run contest throughout the range.
JPEG dynamic range
All of the cameras capture a good dynamic range in their JPEG files but the Sony A7S appears to cope significantly better than the Nikon D4S at the higher vaules.
Raw (after conversion to TIFF) dynamic range
Again the Sony A7S beats the Nikon D4S at the higher sensitivity values, indicating that it can capture a wider range of tones in a single shot. The Panasonic GH4 does best its mid and high values though.