The term 35mm camera type can refer to a variety of different cameras. Leica is a 5 letter word that refers to a German camera manufacturer that produces high-end cameras and lenses. Leicas is a 6 letter word that is the plural form of Leica. EOS is a 3 letter word that stands for Electro-Optical System and is a line of cameras produced by Canon. LENS is a 4 letter word that refers to the optical component of a camera that focuses light onto the film or digital sensor. SLR is a 3 letter word that stands for Single LENS Reflex and is a type of camera that uses a mirror and prism system to allow the photographer to view the image through the LENS.