This graph shows the signal-to-noise ratio of three popular DSLR cameras with our DXA-SLR ULTRA adapter verses two standalone digital audio recorders. The test was done by feeding all devices the same -55dBu input signal which would be typical of the output level of many microphones. The recording level was adjusted to -12dBFS (Full Scale) on the VU meter. A S/N ratio over 40dB is good and over 60dB is excellent.
Note that the audio performance of the cameras is actually better than the Zoom H4n and almost as good as the Tascam DR-60D. Recording audio directly to the camera is far easier and does not involve having to use an external audio recorder or having to sync in post.
Find more information about the DXA-SLR ULTRA here.