= 12. Semi-Interquartile Range. The semi-interquartile range of a distribution is half the difference between the upper and lower quartiles, or half the interquartile range. Therefore, from the example above, it was determined that the interquartile range = 12.
Electronic Viewfinders (EVFs) An EVF is basically a very small screen inside a viewfinder, so you can put your eye up to the viewfinder and use it like a traditional camera. On most cameras with EVFs you can switch the view between the viewfinder and the rear LCD screen interchangeably.
Optical Viewfinders (OVFs) An Optical viewfinder is usually used in SLR cameras. It is a glass prism that allows you to see the view through the lens. The light comes through the lens, hits a mirror, then bounces up into the viewfinder prism, where it is bounced towards your eye.