Quote Originally Posted by paulnj
A few budget lenses I would suggest would be....

...A straight 400F5.6 tokina or sigma lens(USED as they are replaced by zooms which sell better), they sell used at $200-300 average and my tokina got me years of quality images.

.... Sigma 170-500 or 50-500 will give you GREAT images if you properly support it(heavy tripod/ beanbag ) Both lenses are capable of great salable images! I got a 170-500 7 years ago? and it served me well until switching to canon a few years back

.... 300F4 lens with a matching 1.4 TC.

And the last option.... RENT a 200-400 f4, 500f4 . That will be costly though.

I have seen images from both 80-400's you mention and they seem to be no sharper than my 400f5.6 images or 170-500 images VR/OS will help steady you gear in lower light situations, but will not stop subject movement.
Paul this post is very insteresting to me right now. Do you think with much practice and planning for the shoot properly one can get away with shooting heavy long focal length lenses WITHOUT some form of image stabilization in the context of wildlife/nature photography. I'm trying not to spend extra on the IS version of the Canon 70-200 L f/2.8.

Maybe you've read my rant in other threads

As to not highjack the thead...here's my .02.

Another alternative using Sigma gear is the Sigma 70-200 f/2.8 with 2x TC. If you can get the older non macro, you'll save over $100 from the newer one (B&H). The new version with macro doesn't really get you very close IMO. The Sigma 70-200 has received very good reviews and it's an EX version meaning the build is pro. Although, you can't beat the price on that Sigma 170-500.

Good luck and I hope you post those photos when you get back.