Originally Posted by Rocket79

Please consider two cameras. One with the shorter focal lengths and one with the longer one. This way, you won't have to change lenses. And if the unthinkable happens and your camera is damaged or fails to work, you'll have back up. I'd never travel that far without two cameras and I've been on safari many times. In Tanz, you'll want the reach, even for larger animals that are in the distance. Just remember that there will be atmospheric distortion at those longer lengths, especially midday.

Originally Posted by Gardyloo

We don't know if the 100-600mm lens is the only one the OP owns. I guess my suggestion would be that if the purchase of second lens is being contemplated, then maybe looking for a decent wide > tele zoom might be the smartest move, rather than a dedicated wide lens.

I bought a Tamron 18-400mm zoom for my Nikon DSLR (back before I downsized from DSLRs to a Lumix bridge camera with which I've been super pleased, as has my wallet) and the Tamron zoom became my default lens for all sorts of travel. It's not the sharpest or fastest lens in the pack, but it was affordable and gave me plenty of good images to play with in post. You can get a used one for under $400 or $500, which might be an alternative for the OP.