Das Samyang pro 14mm 1:2.8 ED AS IF UMC is the only lens with manual focus in my photo bag that I use on my Canon cameras. And there is a good reason for that.
The inexpensive, bright ultra-wide angle lens delivers impressively sharp shots on all Canon full-frame cameras, including the EOS R. It is used by me for landscape and interior photography.
Especially for night shots, the lens delivered the best quality, almost without Coma errors in the lights and is therefore excellently applicable for video and time-lapse shooting.
In the meantime I also use the lens on the Panasonic GH5 with the Metabones XL adapter or the Commlite adapter.