In article , Alfred
Molon wrote:

If you look he
https://www.youtube.com/watch?v=eFFNZYNYxFQ

these lenses have absurd sizes. It's not something you would
carry around for hours/the full day while walking in a tropical
rainforest.

those are toys compared to this:
https://petapixel.com/2012/10/15/the...-at-the-sigma-
200-500mm-bazooka-lens/