One big difference between video and film is that some film cameras can be cranked up to much higher than 24 frames per second, capturing full frames 75 or 100 times per second, making for perfect, silky-smooth slo-mo.
The only way to approach this effect in video is to interpolate pixels between frames. (Most programs simply dissolve between slower frames which is definitely not the same thing!
Twixtor is a software plugin that enables you to speed up, slow down or frame rate convert your image sequences. Twixtor synthesizes unique new frames by warping and interpolating frames of the original sequence… employing RE:Vision’s proprietary tracking technology that calculates motion for each individual pixel.
I have not worked with this plug-in and it is a bit expensive but it could be the answer for video projects needing smooth slow motion.