The fourth image perhaps speaks most to the light gathering power and low read noise of the sensor

Scaled for pixel size, the 5D IV has lower upstream read noise than the III

Shadows are much cleaner - at base ISO, the IV has less than half the read noise of the III

This performance suggests that the 5D Mark IV is a good camera for astrophotography, because a lower read noise should translate to better signal to noise ratio across the board, but especially importantly for the low photon flux from deep sky objects

Seems to me that Canon wanted to protect the 5DS/R from being cannibalized from a too potent 5DIV

Seems to me that Canon wanted to protect the 5DS/R from being cannibalized from a too potent 5DIV

Already the 5DS/R got improved

As an owner of every EOS 5D model since the original, this model is just as impressive as with each generational upgrade.

At high ISOs, it is the upstream read noise of the sensor, as opposed to the noise from A/D conversion that dominates