ND Filter Calc (DSLR) is a free photography application that helps you calculate the optimal exposure time for your photographs. This Android application is developed by Lars Mathuseck and is available for free. The app is designed to help photographers optimize their photographs by calculating the optimum time span when using neutral density filters.

The app has a simple layout that is easy to use. You can select one or multiple filters to add to your custom filters. The built-in timer/alarm comes with optional vibration and sound features. The app provides accurate calculations to help you get the best results for your photographs.