Canon 60 f/2.8 vs. 50 f/1.8

Thanks for the advice. I don't want to get off topic, are these the official "full" f-stops (1.4, 2, 2.8, 4, 5.6, 8....)? So, is there ~ 1 1/4 to 1 1/3 full stops between 1.8 and 2.8 (rather than 2x more light?)?

Appreciate all of the responses. Thanks.