The invention relates to the technical field of monitoring, in particular to a snapshot method and device and a camera. The snapshot method comprises the following steps: after a predetermined snapshot position is determined, obtaining a position angle parameter and a multiplying power parameter corresponding to the predetermined snapshot position; obtaining a snapshot focus parameter of the camera according to the position angle parameter and the multiplying power parameter; adjusting the focus of the camera according to the snapshot focus parameter; and enabling the camera to perform image snapshot at the predetermined snapshot position. According to the invention, the snapshot focus during snapshot of the camera can be directly set, the time for searching the focus position is reduced,the focusing time consumption is short, snapshot can be carried out in real time during monitoring, the focusing effect is good, and the fuzzy state of a shot picture is reduced to a certain extent.