Without a Permit: If you arrive in Ethiopia with binoculars and no pre-approved official permit, customs and security officers at the airport will confiscate them. You will be given a receipt, and your binoculars can typically be collected at the airport security office upon your departure from the country.
With a Permit: To bring them in legally, a certified local tour operator must apply for and secure an official clearance letter from the Ministry of Tourism and INSA well in advance of your arrival.
Transit Passengers: If you are staying strictly inside the international transit area at Addis Ababa Bole International Airport and not passing through immigration into the country, standard carry-on binoculars are generally not confiscated, though security screenings still apply.