How to zoom in into an environment texture ? I chose cycles render as the render engine, 
went into the world panel, 
clicked in the surface part onto use nodes 
and selected from color environment texture. 

Now when I am in the rendered mode of viewport shading, 
I can see the texture environment and it lights my glossy
cube as it should be, but when I scroll the mouse-wheel, 
the size of the cube changes and the size of the environment texture
stays the same.

How can I achieve to move with a camera inside this environment texture and zoom into parts of it?
add a node "coordinate texture" to environment texture and scale only "X" and "Y"