Just sharing with everyone. When we 'calculate' the 35mm-equivalent focal length for APSC cameras, we usually multiply the focal length by it's crop factor. But we often forget about the equivalent aperture value.
50mm F1.8 lens on a Canon APSC camera is actually:
1.6 (crop factor) x 50mm = 80mm, 1.6 (crop factor) x F1.8 = F2.88 [on a full frame camera].
Hope everyone find this useful.