I recommend editing %localappdata%\Frontier Developments\Elite Dangerous\Options\Graphics\Settings.xml file for FoV because optimal value for me was above maximum of the slider.
^this.
The slider doesn't go near far enough.
I use just a little more the slider - 63, so that I don't lose sight of my hud during high-g manoeuvres, but you can experiment to find a setting that suits you.
Cut and paste this folder link ' %localappdata%\Frontier Developments\Elite Dangerous\Options\Graphics ' into your folder explorer, then use notepad to edit 'settings.xml'
The line you're looking for is about halfway down: <FOV>63</FOV>
Have a play
