Tanzania customs to visit Serengeti, Kilimanjaro, and Zanzibar for you to be familiar with. You can Import(temporarily) these free of duty; binoculars, film, and cameras. But professional video/film, radios, tape recorders require the custom bond to make sure that you export them.
Firearms require permit in Advance. Also, remember to keep cash sales receipt if you buy local handcraft. And also,ownership certificate for wildlife trophies for presentation to customs officials on departure.