With a 190? guide number at ISO 100 and 105mm, the Yongnuo Yn-560 ii Flash is a powerful manual flash unit able to be triggered in a variety of methods. The flash can be triggered optically with either instant sync or skip pre-flash options for simpler off-camera firing. Also, the unit is quite versatile with a zoom range of 24-105mm, which is able to be expanded to 18mm with the built-in wide-angle diffuser. Additionally, yongnuo yn-560 ii this output can be adjusted from 1/1 to 1/128 power in 1/3 and 1/2 EV steps.