Benefit of fixed vs variable lens

ias

n3wb
Jan 19, 2018
7
1
Let's say I need a camera to id people who are standing at a gate or doorway. So I know the exact distance the camera will be mounted from the only location a person could be standing.

Is there any benefit to getting a camera with an adjustable focal length vs a fixed? I'm assuming every other variable (other camera specs, lighting, mount location, price, etc.) is identical.
 
ahh...so zooming to fill the frame with just the person's upper body, vs using the fixed lens FOV which might restrict you to showing his entire body?

Would you typically select about 2 lens plus or minus around your ideal fixed lens to give you that adjustable FOV?