Background grid warping when zooming in User Persp New Install
Blender 2.7b
Ubuntu 16.04LTS



Whenever I zoom in User Perspective mode, the background grid warps alot as you can see on the bottom right of the first image below:



it returns to normal when I zoom out or in orthographic mode:




I think this might be because of the small screen size that I have (1366x768), or because of some settings in Ubuntu, but I can't quite work it out. What should I do to fix this problem because it is very annoying. Thank you for your time.

--A Blender newbie
This is a normal wide-angle perspective distortion. To reduce it, you need to look at your subject through a longer lens from further away. 

Bring up your right-hand panel (hotkey N) find the 'view' section, and change the 'lens' length to a higher number, and track back using the middle mouse wheel.

The longer the lens, and the further away you pull back the camera, the more closely the view will approximate to orthogonal, just as in real-life photography.