Money!!!

[Warbler]

First time I've seen the Sigma 200-500 F2.8 being used in the wild. $25K and weighs heaps.

http://bokeh.digitalrev.com/article/photographer-looks-to-the-stars-captures-glorious-rainbow-contrail

[Mary Anne]

Interesting and at almost 16kg its a tad too heavy for me :D

[Morgo]

Certainly is an cumbersome beast.

[Mark L]

I'm not even going to click on your link. :hb: