An imaging device (100, 100') comprising: • a first imaging system with a first lens system; • a second imaging system with a second lens system; and • an auto focus controller adapted to: initially obtain a result of an objective function for each of the first lens system and the second lens system in a predetermined position in a common initial search range and store, for each of the first lens system and the second lens system separately the respective obtained result of the objective function as a stored best result; perform a step by step auto focus search with the first lens system and the second lens system on the basis of a search parameter; obtain a result of the objective function for each of the first lens system and the second lens system after each auto focus search step; compare, after each auto focus search step, for each of the first lens system and the second lens system the corresponding obtained result with the corresponding stored best result and determine whether the corresponding obtained result is better than the corresponding stored best result; if the corresponding obtained result is better than the corresponding stored best result, update the corresponding stored best result with the corresponding obtained result; update, after each auto focus search step, the search parameter depending on the result of said comparison. • a first imaging system with a first lens system; • a second imaging system with a second lens system; and • an auto focus controller adapted to: initially obtain a result of an objective function for each of the first lens system and the second lens system in a predetermined position in a common initial search range and store, for each of the first lens system and the second lens system separately the respective obtained result of the objective function as a stored best result; perform a step by step auto focus search with the first lens system and the second lens system on the basis of a search parameter; obtain a result of the objective function for each of the first lens system and the second lens system after each auto focus search step; compare, after each auto focus search step, for each of the first lens system and the second lens system the corresponding obtained result with the corresponding stored best result and determine whether the corresponding obtained result is better than the corresponding stored best result; if the corresponding obtained result is better than the corresponding stored best result, update the corresponding stored best result with the corresponding obtained result; update, after each auto focus search step, the search parameter depending on the result of said comparison. initially obtain a result of an objective function for each of the first lens system and the second lens system in a predetermined position in a common initial search range and store, for each of the first lens system and the second lens system separately the respective obtained result of the objective function as a stored best result; perform a step by step auto focus search with the first lens system and the second lens system on the basis of a search parameter; obtain a result of the objective function for each of the first lens system and the second lens system after each auto focus search step; compare, after each auto focus search step, for each of the first lens system and the second lens system the corresponding obtained result with the corresponding stored best result and determine whether the corresponding obtained result is better than the corresponding stored best result; if the corresponding obtained result is better than the corresponding stored best result, update the corresponding stored best result with the corresponding obtained result; update, after each auto focus search step, the search parameter depending on the result of said comparison.