DxOMark has published the Sony a6400 sensor review and test results: “The Sony A6400’s APS-C size CMOS sensor achieves an overall DxOMark score of 83 points (just 2 point behind the Sony a6500), which puts it on the same level as slightly older APS-C models, such as the Nikon D7100 and the Samsung NX1″.
Conclusion from DxOMark:
Anyone comparing the Sony A6300 and A6400 will find the results intriguing. Although the two models share a similar sensor resolution (pixel count) and the overall results are very close, the measurements are not identical.
Despite its slightly higher noise floor over the A6300, the new A6400 sensor performs well, combining a wide dynamic range over a highly useful range of ISO sensitivity settings and excellent low-light ISO capabilities. Although that directly impacts the color depth, the A6400 remains capable of delivering extremely pleasing images. Combine those attributes with the new AF system, 11fps continuous shooting, and a relatively affordable price, and you have a very enticing camera for sports and action photographers on a budget.