I was looking on the PhotosToPhotos.com website recently to see if there was information there on the dynamic range of the 5D Mark III with dual iso.
I was surprised that the 5D Mark III wasn't listed, (though there was info for the Mark II), so I contacted the website owner and offered to assist him with gathering data for the Mark III, which he has now posted to the website. Should you be interested, here's the link comparing the standard Mark III with ML dual-iso base settings of 100 and 400 ISO : https://www.photonstophotos.net/Charts/PDR_MagicLantern.htm#Canon%20EOS%205D%20Mark%20III,Canon%20EOS%205D%20Mark%20III_16(ML),Canon%20EOS%205D%20Mark%20III_16(ML400). The results suggest a dynamic range improvement of approx 1 bit over the 5D Mark II.
Its not possible to compare the 5D Mark III with the much more recent Canon R5 on that chart, but reading the separate chart for the R5 here : https://www.photonstophotos.net/Charts/PDR.htm#Canon%20EOS%20R5 suggests that the Mark III does well for dynamic range, albeit with a lower resolution.
I was surprised that the 5D Mark III wasn't listed, (though there was info for the Mark II), so I contacted the website owner and offered to assist him with gathering data for the Mark III, which he has now posted to the website. Should you be interested, here's the link comparing the standard Mark III with ML dual-iso base settings of 100 and 400 ISO : https://www.photonstophotos.net/Charts/PDR_MagicLantern.htm#Canon%20EOS%205D%20Mark%20III,Canon%20EOS%205D%20Mark%20III_16(ML),Canon%20EOS%205D%20Mark%20III_16(ML400). The results suggest a dynamic range improvement of approx 1 bit over the 5D Mark II.
Its not possible to compare the 5D Mark III with the much more recent Canon R5 on that chart, but reading the separate chart for the R5 here : https://www.photonstophotos.net/Charts/PDR.htm#Canon%20EOS%20R5 suggests that the Mark III does well for dynamic range, albeit with a lower resolution.