If it's like 5D4, it's very unlikely, as
1080p60 appears to be pushed to the limit. That's an unexpected limitation, since on both models, the sensor
appears to be fast enough for 1080p120, assuming no readout overhead for lower resolutions.
5D3:
5936x3950x7.65 = 179 Mp/s (full size, including black bars, in photo mode)
5796x3870x7.65 = 171 Mp/s (active area size)
3744x1382x31.5 = 163 Mp/s (full size, including black bars, 1:1 crop x5)
3596x1320x31.5 = 149 Mp/s (active area size)
2080x1320x40 = 109 Mp/s (full size, including black bars, 3x3 binning 1080p FPS override)
1936x1280x40 = 99 Mp/s (active area size)
2080x1040x48 = 104 Mp/s (active size, 3x3 binning crop_rec)
1936x1040x48 = 97 Mp/s (active size)
700D (LiveView figures from the
bleeding-edge crop_rec):
5280x3529x6.45 = 120 Mp/s (full size)
5208x3476x6.45 = 117 Mp/s (active size)
2592x1107x33.3 = 95 Mp/s (full size, 1:1 crop x5)
2520x1080x33.3 = 91 Mp/s (active size)
1808x1189x43.3 = 109 Mp/s (full size, including black bars)
1736x1160x43.3 = 98 Mp/s (active size)
In other words:
- 5D3 1080p (1936x1280) was pushed to 40 FPS, i.e. about 100 Mp/s out of 170 in photo mode (what limits it? no idea)
- 700D 1080p (1736x1160) was pushed to 43 FPS with a slower sensor, i.e. about 100 Mp/s out of 120
Take it with a grain of salt, i.e. as pure speculation or CR0 if you prefer; I did not see the EOS R firmware.