The designation DG indicates that the lens has been optimised for digital SLRs but is equally compatible with film SLR cameras. These will work on digital SLRs with a small (APS-C size) image sensor, digital SLRs with a full frame sensor and film SLRs. DC lenses are designed specifically for digital SLRs with the small, APS-C size image sensor. These are not suited for full frame digital or film SLRs as heavy vignetting will occur.