Artcameraman Loc: Springfield NH

Colombia? I would take an S&W 629 with plunty of ammo.

mwsilvers Loc: Central New Jersey

None of the Canon extenders will work with that lens. I believe the Tamron teleconverters are also not compatible with the Tamron 18-400. The 18-400 superzoom is intended as a casual vacation walk around lens, and while it can provide pleasing results for many people it is not a high quality optic and may not meet the needs of most discerning photographers. I had one for a over a year and it was a lot of fun to use because of it extreme focal range but in the end I wanted better results from my images and sold it.

Cubanphoto

I lived in Colombia (notice the spelling) for 8 years. It is beautiful, the scenery varies from area to area as well as the wild life. You have snow covered mountains and near jungle in the Amazon (not the e commerce Co.) or the extensive plains of Villavicencio or La Costa (the coast up north).
If you tell me where your son is or if you plan to travel around a particular area, then I could recommend some lenses.
Most import taste the food, drink the coffee and the Aguardiente - when you drink the latter, you'll take better pictures!

scoundrel Loc: Wytheville VA

Getting one of those on the plane might prove to be the longest and most complicated parts of the trip.

Retired CPO Loc: Travel full time in an RV

Yep! And you would still end up dead if you made it to Colombia!

Architect1776 Loc: In my mind

I made it with my M1911 and M16 in and out.

Leaning Ladder Loc: Bethlehem, Pennsylvania

Based on my 5 trips to Colombia, including the Andes, the 18-400mm should meet your needs. The 50mm buys you nothing (except some sharpness on close subjects), and the 10-18 may be helpful in towns, but will otherwise be useless, as will your TC. That 150-600 is large and heavy, so unless you will be doing a lot of birding from a distance, and can safely travel with it, leave it at home.

I'll add this: Colombia is one of the most beautiful countries I've visited. It's quite safe in most places (unlike how it was 30 years ago), people are generally quite friendly to tourists, the food is amazing, and you're certain to get many great shots. Hopefully you'll get to the Cocora Valley, with some of the most incredible landscape on the planet. Enjoy your trip!

mizzee Loc: Boston,Ma

I’d bring the 18-400, 50, and 10-18 for wide angle.

ackvil Loc: Delray Beach, FL