500 f/4L vs. 600 f/4L

[adam]

Rent a 500mm f/4 for a week (LensRentals carries it), take it out for a spin, and see how you like it. That will give you a much better feel for whether or not you want to spend the extra money on (or want to carry) the extra 100mm. Depending on the kind of light you get, you might do ok with the 500 f/4 and a teleconverter. Or maybe not...it's easier to make an educated decision once you've used it.


Also, keep in mind that you're probably going to spend another $1200 on a tripod setup to hold a lens like that, if you haven't already...

[ShutterbugJohan]

If you have the 100-400, the 600mm would probably be the better choice.