i took my camera with R5, 4Kraw recorder unit from Sony Japan, for shooting some nice seashore stuff in enoshima area.
DCI4K sized raw "120fps burst mode" gives me around 18 sec. of quite nice super slow motion. not so super super slomo but it's very comfortable to edit with.
please note that most footage taken with EF 70-200mm F2.8 IS. 4K shooting + manual focusing = serious stuff, need more time to get used to it.
for pixel peepers, here's the link you can download the image set from the original 4K cinemascope size :
i would like to say thank you for Sony Japan. domo arigato for letting me to play with.