First, we need to know the size of the test object and working distance between the lens and the test object. Then, select a suitable lens by referring to section 1.3 , the "Camera and Lens" table in Chapter 1 of the DMV1000 Technical Manual. For example: According to the manual, if a 25mm focal length lens is used when the working distance is 235mm, the field of view can reach to 45mm x 34mm (see the figure below). So, if the size of the test object is 30mm x 30mm and the working distance between the lens and test object is 200mm, using a 25mm focal length lens is suitable for meeting the customer's requirement.