The front of the filter holder features laser-etched markings, which correspond to fractions of the frame. For example, the first mark above the holder's centre line corresponds to approximately one third of a 35mm frame.
The line above athat marks the top of the frame, As a result, accurate positioning of the filter is possible even when the effect cannot be viewed through the lens. Equally importrant, it is quick to use, allowing the photographer to respond to rapidly chaning conditions.