A system for determining a recommended magnification factor and/or a recommended range for magnification factors for a magnifier such as a loupe or an electronic magnifier to be used by a person wherein the system comprises at least one test object having a predetermined size and a portable camera for recording an image of at least a portion of the at least one test object and displaying at least a portion of the image of the at least one test object to the person, wherein the camera is provided with a light sensitive sensor for obtaining an image of at least a portion of the at least one test object, a display and processing means for processing the image obtained by means of the sensor and for displaying at least a portion of the image of the at least one test object on the display, in possible a magnified form, wherein the camera is provided with means for selecting the magnification of the at least one portion of the image which is displayed on the display and wherein the camera is arranged to calculate the recommended magnification factor and/or the recommended range for magnification factors on basis of a predetermined algorithm wherein the predetermined algorithm uses as parameters: a value representing the selected magnification for the displayed at least one portion of the image, the size of the at least one test object and a distance between an eye of the person and the at least one test object while the at least one test object is seen by the person by means of the portable camera； and/or parameters which can be derived from the value representing the selected magnification for the displayed at least one portion of the image, the size of the at least one test object and a distance between an eye of the person and the object while the at least one test object is seen by the person by means of the portable camera.
