- Weight of Mamiya C330 with standard lens: 1.7 kg (3.7 lbs)

- Weight of Mamiya RB67 with back and standard lens: 2.5 kg (5.5 lbs)

- Weight of Rolleiflex Automat: 0.85 kg (1.9 lbs)

- Weight of Rolleiflex 3.5F/2.8F: 1.2 kg (2.6 lbs)

- Weight of Zeiss Ikon Ikonta 521/16 (6x6 folding camera): 0.45kg (1 lb) / this is approximate, because there were numerous models with different lenses and shutters. But this probably is reasonably accurate. The Super Ikonta models -- particularly the 531/16, 532/16 and 533/16 -- weigh significantly more (and cost more, too).