What is the minimum length of a slider for interviews?

[haring]

Hey guys!
What is the minimum length of a slider for interviews? I would like to make some company, small business interviews and I would like to add motion effects. I would like to keep it portable, as well. Any suggestions?

[Peter McLennan]

One meter. 

Useful too, IMO.

I'd avoid powered ones unless unmanned operation is essential. Smooth stops and starts are hard (expensive) to implement.

[Joe Towner]

Shoot in 4k & wider than you would think, then zoom down to HD & do the motion in post.  Premiere & Resolve can both do it.

[Martin Kristiansen]

Shoot in 4k & wider than you would think, then zoom down to HD & do the motion in post.  Premiere & Resolve can both do it.

Which will give an effect much the same as panning on a tripod and will in no way replicate the effect of a slider.