500D: • 9-point CMOS sensor • F5.6 cross-type at center, extra sensitivity at F2.8
7D: • TTL-CT-SIR CMOS sensor • 19 cross-type AF points (f/2.8 at centre) • Center point additionally sensitive with lenses of F2.8 or faster
50D: • 9-point TTL CMOS sensor • All points cross-type for lenses of F5.6 or faster • Center point additionally sensitive with lenses of F2.8 or faster