The Z-Finder Pro 2.5x is an optical viewfinder that allows DSLR cameras to have the correct form factor for video. This Z-finder will magnify the LCD screen by 2.5x and has a diopter for specific focus tuning. It cuts out any extraneous light and offers an initial point of stability by pressing your eye against our comfy, large eyecup. The Z-finder Pro 2.5x comes with a 40mm diameter Zacuto optical designed lens, anti-fog coated protective covers, and a mounting system designed for 3” LCD screens. (A 3.2” version is available.) The diopter allows you to dial in the focus to match your eye. If you need extra focal points you can use the included Z-Finder Extender Frames. These are semi-permanent stackable frames that attach to the body of the Z-Finder Pro and extend the Z-Finder glass further away from the LCD screen for people who are farsighted.