No matter what level of photographer you are, there's no question either simply your smart phone's camera or exceptional quality digital cameras are within the reach and budget of most travellers today. Both have a role to play. While you're smart phone is wonderful for photos and video around camps, on vehicles and when animals are close, you might want to consider something with more substance and specifics to get that award winning shot. Increasingly, mirrorless cameras are taking over from DSLR's, considered by most camera manufacturers to be a thing of the past.
We're all pretty much keen photographers at Epic (Sam has been nominated for a big award!) and our experience over the years has shown us ideally you want at least a 300mm zoom lens on the African savanna or even on the ice in Antarctica. 300 plus opens up a whole new world of possibilities with your images. Do your research and practice before you hop on the plane if you're buying new.
Make sure you have enough memory cards for your camera in case for some reason you're unable to download for a day or two. Ditto with batteries. Nearly all camps are well equipped with charging stations these days. With photographing people, always ask your guide or even the person themselves if you wish, to see if its ok to take a picture. It nearly always is, but better to ask and make sure.