Di Digitally Integrated Design. Optical system designed to meet the performance characteristics of DSLR cameras as well as film cameras. Lenses can be used with either Digital or Film SLR cameras.
Di II Digitally Integrated Design. Lenses made exclusively for digital SLR cameras with image sensors smaller than 24mm x 16mm (APS-C). Features high resolution performance incorporating anti-reflection coating and optical configurations to compensate for internal reflections and ghosting. Peripheral light fall off, more noticeable with digital cameras, is also reduced. Also provide ideal focal lengths to cover the range desired by DSLR users. Not designed for Full Frame Digital SLR cameras.