To determine microns per pixel, measure the field of view at themagnification being used. For example, using the AD413T at its highest magnification (~220x), the FOV is 2.2mm or 2200um.
Take the FOV in microns and divide by the resolution of the Dino-Lite, so in this case we would divide 2200um by 1280 pixels. 2200um/1280 pixels = 1.72um/pixel.
Since the Dino-Lite handheld microscopes offer variable magnification, the microns per pixel will be different with each magnification. The above method can be performed for any magnification you wish.