Why does the direction of the axis changes behaviour in Quaternion.AngleAxis?

I have a camera and I rotate it with the following

  transform.rotation = Quaternion.AngleAxis(45.0f,Vector3.up);

the docs for Quaternion.AngleAxis

Creates a rotation which rotates angle degrees around axis

line above rotates the camera around Y axis( used to turn right and left like in a fps game) 45 degrees to the right.

When the line is modified to:

 transform.rotation = Quaternion.AngleAxis(45.0f,Vector3.down);

I am expecting this to rotate to the right as well since direction of the axis that the object rotates around should not matter.However it rotates to the left, am I missing something very obvious here?