Vivitar V3800n K Mount = 445g SMC Pentax-M 200/4 = 405g Total package w/o film = 845g A bit over 1.8 pounds. Not sure it is the lightest but it is certainly close. The lens gives very, very good image quality, is small for a 200mm and comes with its own slide out metal hood. The camera is surprisingly solid and easy to use with center weighted metering, 1/2000 max shutter speed, timer, mirror lockup when used with timer and a 1/125s flash synch. It is an entirely manual kit.