File:Canon310xl notches.jpg

Canon 310XL notches. The camera manual states that the meter understands 3 film speeds, 40T, 160T, and 250T. Measurement shows you how other notches will be interpreted by the camera. For instance, it appears that a 64T notch such as the new Ektachrome 64T will be read as 160T due to the placement of the notch reading switches.T esting with an actual E64T cartridge confirms this is true: the camera reads E64T as 160 ASA Tungsten.