Slowing down video vs higher framerate recording What is the difference between slowing down the video in software compared to actual shooting at higher framerate?

For example, i have a camera that shoots at 60fps and want to slow it down to achieve the same effect as when shooting at 120fps. What would be the differences?
By shooting at higher frame rate, you can achieve great looking and frame accurate slow motion. Interpolation is not going to happen. But if you want to slow down your footage beyond the frames you have, you can use the right tools in your video editor, or Twixtor plugin, but of course it will not give you as good results as a dedicated high speed camera. Absent frames are digitally interpolated. There are some more affordable Twixtor alternatives, such as Respeeder. These tools will give your video a smooth, high-frame rate look.