This is a format for compact font storage in the OpenType system, allowing for the rasterization of text information. It differs from TrueType in its abilities to describe font symbols and with its font structure variation algorithm, depending on the change in size. CFF allows for increased screen clarity with high resolution, but this is not due to the font, but its rasterization.
This is a format for storing raster and vector fonts created or changed in FontForge. By opening an SFD file in this program you can store it in any modern font format like TrueType or OpenType. SFD contains all the information about the point setting of each symbol created or changed in FontForge.