Imaging system and imaging method

An imaging system comprising:

• an image forming device comprising an optical system having a variable focal length lens capable of changing a focal length to an object within a predetermined range, the image forming device obtaining image information of the object with the focal length being changed by the variable focal length lens, and forming an all-focused image of the object;
• a sensor device that detects variations in a surface level of the object in a direction of focus;
• and
• a position adjustment device that adjusts a position of the object in the direction of focus in accordance with the surface level variations of the object detected by the sensor device,
• wherein the position adjustment device adjusts the position of the object in the direction of focus in a manner such that the surface level of the object becomes closer to the center of a variable focal length range of the variable focal length lens.