The most likely time to damage or break your neutral density filters is taking them on and off your camera. Rather than take your filters off to calculate your exposure time, leave them on and use this simple super fast technique! Given an exposure (Aperture, Shutter speed, ISO), allows calculating equivalent exposures - set 2 new parameters (a combination of Aperture, Shutter and ISO) and the 3rd parameter is automatically calculated. It is also possible to add filters of up to 20 stops each t