In article , Ken Hart
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/

How much is the lens cap? About $500? You¹d need a backpack just for that.


I have the Canon FL-mount 1200mm f/11 lens. It's about 3 feet long, and
fairly heavy- it gets heavier the longer you carry it.

interesting discovery in the world of physics.

perhaps if you carry it long enough, it will weigh as much as this one
does initially, a 1700mm f/4 lens at 256kg/564lb.
https://www.cemec.de/en/worlds-largest-photo-lens.html
https://farm9.staticflickr.com/8307/7841942100_f813136b5e_o.jpg

a more realistic choice is nikon's 1200-1700 f/5.6-8 zoom:
https://www.cameraegg.org/the-zoom-n...6-8p-if-ed-len
s-specs-images-unboxing/

that nikon lens is actually quite easy to carry, and unlike canon
lenses, its weight remains constant.
https://www.cameraegg.org/wp-content...-Nikkor-1200-1
700mm-f5.6-8P-IF-ED-lens-2.jpg

I would never
consider using it without a tripod, which also gains weight.

nothing significant.

I would
never consider it for wildlife.

you should, because it could double as a weapon in case the wildlife
chooses to attack.

one key advantage to canon lenses is because its weight increases, it
becomes more effective for a wider range of wildlife.

the downside is that the lens would end up being coated with blood and
fur and who wants that. at least use a protective filter on the front.

And I will not be walking around a tropical rain forest with it.

your loss. there are many good photo ops in a tropical rain forest.