Okay I understand the other stuff like a wider aperature (lets say F1.4) lets in more light and the DoF is smaller therefore more will be out of focus especially the background... Also that the closer you are to the subject there more the background will be blurred. But what about when it comes to focal length? It sounds like a 100mm will have a deeper blur compared to a 50mm if the aperature is the same. Hmm what does the number mean anyway? Does F/1.4 let in more like on a certain lens than any other lens with F/1.4? such as different brands n models n such? Thanks!