A normal range lens is considered to be one that will not magnify or increase width of the image compared to the human eye.  This range of focal lengths is 40mm, 50mm, 55mm, and 60mm. This classification is only for the standard 35mm full-frame or digital full-frame camera format. If you are using a digital camera with less than this, the focal length must be multiplied by a factor based on the actual size of the sensor. In most cases, this is a multiple of 1.5x, but can vary slightly.