That's a biggie alright, saw this one some time back though and it rates right up there at 256 Kg.
Keep in mind the camera hanging on the back is a Hasselblad
The design of the ZEISS Apo Sonnar T* 4/1700 required new lens assembly techniques and quality assurance methods never before applied in photo lens production – even by Carl Zeiss’ normally high standards. The finished lens weighs a staggering 256 kg (564 lbs.), placing unique demands on the focusing mechanisms. To address this issue, Carl Zeiss developed a totally new way of operating a telephoto lens, including servo controlled aiming and focusing systems like those used in large telescopes and similar instruments for astronomical scientists.
http://www.dpreview.com/news/2006/10/1/zeiss1700f4