 The Sony Alpha a550's main selling point is its dual Live View mode's, Sony's normal secondary; smaller sensor based Live View mode and another which uses the main sensor with no autofocus.The a550 also features a maximum of 7frame/s continuous shooting speed when operating in speed-priority mode and a maximum ISO of 1600 when in auto mode and 12800 ISO when in manual mode.The Sony Alpha a550 is "big brother" to the Sony Alpha a500, an almost identical DSLR with a smaller 12.3 megapixel APS-C CMOS sensor, no 7frame/s continuous shooting and a lower resolution LCD.