The Samsung NX1 has plenty of different slowmo modes. My favorite is definitely the 100p HD and upscaling it to 4K.
First we have a test video with the slowmo upscaled to 4K in post in order to get a higher bitrate from the YouTube compression. It makes it look much better.
This was recorded with vintage lenses.
Next is a test with all the footage is straight form the camera and it has not even been graded. Still looks ok but I prefer the upscaled version. For this I used the Samsung 30mm f2.0.