Image Sensor1/1.8" Progressive Scan CMOS VS Image Sensor1/2.8" Progressive Scan CMOS
Min. IlluminationColor: 0.0028 Lux @ (F1.2, AGC ON),0 Lux with light VS Min. IlluminationColor: 0.005 Lux @ (F1.6, AGC ON),B/W: 0 Lux with IR
The first one will perform a lot better in night scenarios than 2nd one. It is a new hybrid model which does have standard IR + white light for color mode. You can switch between modes.
I would not recommend 2.8 for 8MP , hell not even for 4MP anymore.
1/1.8 is also not as good for 8MP as it is for 4MP, best case scenario would be 1/1.2 for 8MP
If you are patient, theres new series of colorvu 3.0 and darkfighter 2.0 coming out aka G3 cameras, they perform even better during the night times.
Cheers