The SLT-A99 is both the successor to the Alpha 900 and not; it's a full-frame camera like the A900, but is in the SLT line-up rather than the Sony DSLR. This means such DSLR components as a reflex mirror and optical viewfinder have been replaced by a semi-transparent mirror and electronic viewfinder—essentially, this is a DSLR-sized mirrorless camera, with a non-reflex mirror. The SLT-A99 adds to its impressive spec sheet, including a full frame 24MP sensor, an in-built GPS receiver. While much of the camera is trying to say "pro" (e.g. dual SD cards) and weather sealing, the delay the EVF takes when waking from sleep is unlikely to steal many still photographers away from true DSLRs and their optical viewfinder, just as they are not swarming to the NEX or OM-D E-M5.