50mm F1.4 is generally used as a portrait lens, although you can use it in any situation.
With the F1.4 you need to be spot on with the focusing as the depth of field will be minute in comparison to F4 and alike.
what about an allrounder lens, something like a 24-70mm F2.8 Sigma or Canon.
Not the best of lenses, but great allrounder lens, Sigma 28-300mm lens, compact and great for any situation. Reasonable price too.
I use Canon
16-35mm F2.8
24-70mm F2.8
70-200mm F2.8
and a 1.4x TC