Optical systems, including a mechanical body, a display source, a light-transmitting substrate, an optical device, an image processing unit and an image capturing device. The light-transmitting substrate is in communication with the mechanical body. The optical device couples light waves from the display source into the light-transmitting substrate by total internal reflection. The image processing unit is linked to the display source and is in communication with the mechanical body. The image capturing unit is linked to the image processing unit and is in communication with the mechanical body and has a user controllable zoom position.