I have measured the dynamic range from the RAWs. It seems that the EOS R exactly matches the 5D4 performance, except at ISO 100, where it has around 0.2 EV less dynamic range compared to 5D4. Maybe not that bad taking into account that the sensor is now permanently switched on. EDIT: that could merely be related to sample variation (I just have seen that the 5D4 analyzed also showed 0.2 EV less DR in some files).
Here it follows the results, in the same units used by DXO (normalized). Between parenthesis, for comparison, the values from the 5D4 (got using exactly the same measurement procedure from
this forum post, with
this data).
ISO 100
FRO_0007 - 13.46 EV (13.60)
FRO_0150 - 13.25 EV (13.61)
FRO_0181 - 13.42 EV (13.61)
ISO 250
FRO_0078 - 12.91 EV
ISO 400
FRO_0230 - 12.99 EV (12.99)
ISO 3200
FRO_0201 - 10.97 EV (10.98)
ISO 6400
FRO_0362 - 10.13 EV (10.24)
ISO 10000
FRO_0380 - 9.48 EV
Since likely both cameras also share the same physical base ISO (the real ISO related to the labeled ISO 100) the comparison is fair.
The ISO 100 and 6400 pictures were underexposed, but that has been accounted for (assumed always a max saturation of 16383). These results are from the green channel (the EOS R has different read noise in each channel, just as the 5D4 did, likely due to some white balance correction done in the RAWs, which Canon never did in the past and neither has done in the 1DX2 -at least to this degree-).
The EOS R has a "masked" left area (the photodetectors at the left not exposed to the light) of 144 pixels width, compared to 136 in the 5D4. Same for the top (46 compared to 42). So maybe this sensor could be a new design (with similar technology, though). For those that have not heard about them, these extra pixels are not used by all manufacturers, but are a good habit from Canon, because allow good raw converters to improve the noise characteristics.
The 6D2 achieves 11.90 EV of dynamic range at ISO 100 with this same test. So Canon continues 1.55 EV above the old tech, but still 1.45 EV under my A7R3 results (14.85 EV). Come on Canon... you have done only just half of the job!. Meanwhile Sony did upped their performance (the A7R2 topped at 13.90 EV, same sensor as A7R3 but with poorer electronics).
For those interested, these results can be obtanined by downloading
this tool and running e.g.:
C:\> dcraw -E -4 -j -t 0 -s all FRO_0007.dng
C:\> hraw mskstats -i FRO_0007_0.pgm -m 144 46 -c G
ReadNoise=2.73998 DR@30=12.4628 DR@8=13.4246 file { FRO_0007_0.pgm }
image { mean=654.274 min=489 max=15979 } left mask { mean=511.006 min=491 max=531 crop=68x4492+2+50 }
(to know the width/height of the masked areas, a trick is to edit the pgm with gimp and boost the brightness to 125 and contrast to 124).
