Studio lights are big and heavy--impractical for field use. That's why mobile field production often uses "portable spot" lights.

PORTABLE SPOT:

Like a fresnel, the lamp on a portable spot moves in and out to provide control over the hardness or softness of the light. But in reality, the amount of control is pretty small--because portable spots usually don't have a lens.

Portable spots are usually arranged in a "light kit;" a suitcase-type package that includes three lights, light stands and related accessories.