An electronic device , comprising: a first camera module including a first lens set; a second camera module including a second lens set ; and a processor connected to the first camera module and the second camera module , wherein the processor is configured to: move the first lens set to focus on a subject , using an auto focus, AF, value obtained by the first camera module ; evaluate a reliability of the AF value, wherein the reliability of the AF value corresponds to a probability of a focus detection error; based on the reliability of the AF value, calculate a movement parameter of the second lens set, corresponding to a movement parameter of the first lens set, wherein the movement parameters of the first lens set and the second lens set respectively comprise a movement direction to a target location where the first and second lens sets should be moved, such that the subject is on focus; and CHARACTERISED IN THAT the processor is further configured to, while the first lens set is being moved using the AF value, calculate the movement parameter of the second lens set when it is evaluated that the reliability of the AF value is greater than a first threshold; and move the second lens set depending on the calculated movement parameter. a first camera module including a first lens set; a second camera module including a second lens set ; and a processor connected to the first camera module and the second camera module , wherein the processor is configured to: move the first lens set to focus on a subject , using an auto focus, AF, value obtained by the first camera module ; evaluate a reliability of the AF value, wherein the reliability of the AF value corresponds to a probability of a focus detection error; based on the reliability of the AF value, calculate a movement parameter of the second lens set, corresponding to a movement parameter of the first lens set, wherein the movement parameters of the first lens set and the second lens set respectively comprise a movement direction to a target location where the first and second lens sets should be moved, such that the subject is on focus; and CHARACTERISED IN THAT the processor is further configured to, while the first lens set is being moved using the AF value, calculate the movement parameter of the second lens set when it is evaluated that the reliability of the AF value is greater than a first threshold; and move the second lens set depending on the calculated movement parameter. move the first lens set to focus on a subject , using an auto focus, AF, value obtained by the first camera module ; evaluate a reliability of the AF value, wherein the reliability of the AF value corresponds to a probability of a focus detection error; based on the reliability of the AF value, calculate a movement parameter of the second lens set, corresponding to a movement parameter of the first lens set, wherein the movement parameters of the first lens set and the second lens set respectively comprise a movement direction to a target location where the first and second lens sets should be moved, such that the subject is on focus; and CHARACTERISED IN THAT the processor is further configured to, while the first lens set is being moved using the AF value, calculate the movement parameter of the second lens set when it is evaluated that the reliability of the AF value is greater than a first threshold; and move the second lens set depending on the calculated movement parameter. <EOS>