Come on guys, its just basic mathematics...

Glider weight.... 350kg
Glider Ratio.... 35:1
So Drag = 350/35 = 10kg
If your (air-brake) camera produces a drag of 2kg
New Drag = 12kg
Therefor New Glide ratio is 350/12 = 29.2 : 1

If you use 5 cameras you would halve the L/D.
QED.