The Digital SLR 1/2.5 sensor 1.5x crop APS-C sensor 35mm film full frame sensor Sensor size 384 mm 2 25 mm mm 2 Larger sensors => much improved noise! ISO100ISO200ISO400 ISO800ISO1600 Canon A570IS 7.1 Megapixels 1/2.5 sensor 5.74 x 4.3mm (24.7mm 2 ) Area: 3.48 m 2 /pixel images: dcresource.com ISO100ISO200ISO400 ISO800ISO1600 Canon 30D 8.2 Megapixels APS-C sensor 22.5 x 15mm (337.5mm 2 ) Area: m 2 /pixel images: dcresource.com 30D A570IS 8.2 Megapixels 22.5 x 15mm (337.5mm 2 ) Density: m 2 /pixel 7.1 Megapixels 5.76 x 4.29mm (24.7mm 2 ) Density: 3.48 m 2 /pixel ISO100 ISO1600 Effective use of flash Focal length rangesUltrawide Standard zoom Telephoto 36mm Focal length ranges16mm320mm 1200mm Playing with perspective 24mm 110mm Ultrawide19mm Small Depth of Field Uses of small depth of fieldPortraitsFlowers Sports Isolation Continuous shooting Other advantages Short shutter lag Faster autofocus Adjustable in-camera processing RAW images noise, exposure, white balance Disadvantages Size Cost Less versatility with base kit Maintenance