LENS Comparison From Panasonic Website

SDR-H18
Image Sensor (Total) : 1/6" CCD (680K pixels)
Image Sensor (Effective): 4:3 -- 340K x 3, 16:9 -- 460K x3
F Value: F1.8 (Wide) / F3.7 (Tele)
Focal Length: 2.3 - 73.6 mm

SDR-H40
Image Sensor (Total): 1/6" CCD (800K x 3 pixels)
Image Sensor (Effective): 4:3 -- 290K, 16:9 -- 380K
F Value: F1.9 (Wide) / F4.3 (Tele)
Focal Length: 1.8 - 75.6 mm

Above is the information from the Panasonic website: Link

It seems to me that the image sensor has been increased to 800k pixels in the SDR-H40, but the effective portion has decreased significantly. From this data is seems as though the SDR-H18 lens will outperform the SDR-H40. Am I drawing the correct comparison from this data? Which model has the advantage in the other data (focal length and F Value)? I was looking at the SDR-H40, but if it is actually a decrease in quality over the SDR-H18, I don't know.. Any help would be appreciated.

Thanks!