What are the differences between a lens with an aperture of f 1.8 and a lens with an aperture of f 1.4?

A lens with an aperture of f 1.8 allows less light in compared to a lens with an aperture of f 1.4. The f 1.4 lens has a wider aperture, which means it can capture more light and potentially produce sharper images with a shallower depth of field.