reset 'field of view' (to 40) in perspective view?

Hey folks,

does anyone know how to reset the 'field of view' to 40, in the perspective view (not the camera view?)

Probably most people don't even know how to change the 'field of view' in the 'perspective' view .... you do it by holding shift while zooming. You may ask why did I do this in the first place? .... well, it's a habit I got into when things don't show up in the editor, especially in orthographic view (I learned this trick on this forum, Martin posted the secret shift trick in response .... very good move if you're in that weird situation when things disappear when you zoom out, in orthographic mode) ....
Here, to prove it, go to 'camera view' in the editor, then go to properties of your camera, then hold shift and zoom in and out, and watch the "field of view" change. So that's all well and cool, but you can also do this in the perspective view. the same thing clearly happens, but you can't see the number. Would like to reset this number to 40 ... wondering if anyone knows how to access this number (for the perspective view) and/or how to reset it to 40? i suppose i could just eyeball it but it would be nice to know what I'm dealing with. Hope this makes sense ...