Pretty simple arithmetic..
If a 747 has an internal volume of roughly 27,000 cubic ft(figures are a rounded sum of the main and lower deck cargo volumes of a 744F and close enough for this exercise.)
A cubic ft of air at 70deg f at Sea level weighs 0.0745lb/cubic foot.
27000 x 0.0745 = 2011lb, near enough to the ton you had heard about.
At cruise altitude and a cabin altitude of 8000ft (1 cu ft of air weighs 0.0554lb)
27000 x 0.0554 = 1495lb, somewhat less than one ton.
Note figures for pax version would be lower still as more of interior volume would be taken up with seats, fittings etc.
Don't have the interior vol details for A380, but you get the picture.
If your camera sends text messages, that could explain why your photos are rubbish!