The Z-Finder Jr. is one of Zacuto's Optical Viewfinders that allows DSLR cameras to have the correct form factor for video. It offers 2.5x focusable magnification, a 40mm diameter Zacuto optical designed lens, an eyecup preventing extraneous light leakage, and a field of view perfectly matched to 3" LCD screens. The Z-Finder Jr. does not have a diopter instead it uses Z-Finder Extender Frames to adjust the focal point. The Z-Finder Jr's focal point is -2.75 and up (unlimited with extender frames). The Z-Finder Extender Frames attach to the skirt of the Z-Finder Jr. and allow you to semi-permanently stack the frames until the LCD screen is in focus for you. The Z-Finder Jr. uses a mounting bracket that must be sandwiched in between a tripod plate and the camera. The bracket mounts to the _ 20" screw on your tripod plate and the actual Jr. is held in place with pressure from the fork of the bracket it sits in. You also have the option to mount the Z-Finder Jr. using the Z-Finder Mounting Frame (snap fit adhesive mounting frame) which is also included.
Note: The Z-Finder JR (with included mounting bracket) will only work on small body DSLRs such as the Canon 5D/7D. If you would like to use a Z-Finder JR on a small body DSLR with a battery grip, or a taller body camera like the Canon 1D Mark IV, you will have to use the Gorilla Plate, as well as the battery grip frame or taller frame, or the snap fit mounting adhesive frame. The mounting bracket that is included with the Z-Finder JR only works on small body DSLR cameras.