Do you mean [WIKIPEDIA]Depth of Field[/WIKIPEDIA] or [WIKIPEDIA]Field of View[/WIKIPEDIA]? It seems like you meant the latter.
The sensation of speed in a game is incredibly subjective (although the back-to-back comparisons of various FOV settings are usually self-evident) - as such, I think it might be beneficial to allow setting the FOV according to personal taste, especially now that face-tracking is available (effective or otherwise.) The irony is that having a custom FOV will mess up the DOF effect (at least as it was in GT5
) since it seems to be based on a fixed screen-width / FOV setting, and errors are visible, when replay cameras zoom in and out, on things like overhead cables, e.g. at Eiger.
So your question about custom FOV would be welcomed by "serious" gamers, and is a source of credibility for the sim crowd. I don't really care too much, so long as I can see where I'm going