I went to South Africa in June / July for my first ever safari. I used a Canon 7d2 with Sigma 120-300 f2.8, along with 1.4x and 2x TCs. This was backed up with a 5d3 and 24-105L. There were occasions when I needed a lot of reach, mainly for birds and smaller animals. On other occasions the animals were extremely close and the wider lens was a necessity. A lot of the game drives will be early and later in the day to get the best sightings and best light. This will mean that there is not always a lot of light, so a wide aperture may help. What you might see and how close it gets will probably depend on where you go in Africa. We thoroughly enjoyed our time and both agreed it was our best ever holiday. Sometimes it was good to put down the camera and just enjoy the situation. We were surrounded by a herd of 20-30 elephants of all sizes, with the only light being the full moon on their backs. I didn’t get any shots, but it was an amazing experience. The next night we had a similar experience with a herd of Cape buffalo. Enjoy yourself!