If you notice a document looks blurry on the display, try moving the lens a bit farther from the surface of the document. Some document camera lenses have a focus ring. Some document cameras have a close-up lens attachment that you use when displaying small documents. However, if you’re viewing a large document with the close-up attachment affixed to the lens, the text may appear blurry. Dirty lenses can also cause a blurry text display.