While most people would have a hard time telling them apart, Olympus’s Pen E-P3 and E-P2 have some serious differences under their metal exteriors.Though still 12.3MP, the new P3 ($900, street, with 14–42mm f/3.5–5.6 or 17mm f/2.8 lens) has a new LiveMOS Four Thirds sensor with a faster data readout to enable 1080i 60-fps video, and faster AF speeds than its predecessor. It also has a new TruePic VI dual-core processor, 3-inch 614,000–dot OLED touchscreen, and a 3D shooting mode like the one Olympus put in some compact cameras this year.In the Test Lab