This is the official patch of the "f/2.8 Fast Glass Around the Derby Track" group on Facebook for derby photographers. According to photographer Dan Crowther...
"F/2.8 refers to the typical maximum aperture of the lenses needed in shoot low light while still maintaining a shutter speed fast enough to capture action. The lower the F number the more light a lens can let in which helps offset the fast shutter speed needed to stop fast action without blur. 'Fast Glass' is a generic term used by photographers refer to lenses that are capable letting in more light than the standard lenses sold with the camera from the store (those lenses are known as 'kit lenses' and often have a max aperture of F/3.5-F/5)."