Fundus cameras are used to image the interior of the human eye, including the fundus, retina, macula and optic disk. While a fundus camera is frequently incorporated into a larger eye testing system, there are situations in which they work best as separate hardware. A good fundus camera will have a high quality CCD of up to 12.3 megapixels, reliable auto-focus and auto-shoot capabilities, and good data storage with a choice of multiple image file formats. The customer will notice redundant capabilities amongst products by the same company; this is because many products are separated by the kinds of lenses they take, such as Zeiss or Nikon, but otherwise accomplish the same tasks. Like most eye testing systems, they provide filters for blue, red, green and fluorescein angiography.