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
In terms of JPEG signal to noise ratio, the A7 puts in a consistently good performance. It is very close to the Nikon D600 at the expanded ISO 50 setting, while at the standard ISO 100, it's very close to both the D600 and the Canon EOS 6D. At the mid-range (ISO 200-1600) it is beaten by the Canon, but performs better than the Nikon. Once we get into the higher ranges (ISO 3200 and above), the A7 steals the lead comfortably.
Raw signal to noise ratio
When shooting in raw format, the A7 doesn't fare quite so well. It is below both the Nikon D610 and the Canon EOS 6D throughout the sensitivity range, being more closely matched to the NEX-7 which features an APS-C sensor. This may be indicative of the camera allowing you to fine tune noise control in raw format files though.
JPEG dynamic range
Throughout its native ISO range (ISO 100 -25600), the A7 performs with consistency. Although it doesn't quite match the Nikon D600 at the lower end of the scale, it does beat the Canon EOS 6D. At the higher end of the scale (ISO 1600 and above), the A7 outperforms the other cameras on test.
Raw dynamic range
When shooting in raw format, again the A7 is less consistent, which could also be an indication of the control you have over raw files yourself. At the lower end of the scale it is fairly closely matched with both the Nikon D600 and Canon EOS 6D, but it loses out quite significantly to the Canon in the upper reaches of the sensitivity scale.