NiSi Filters Exposure Calculator (Free)
Use the NiSi Filters app to calculate the exposure time when using NiSi ND filters, and to trigger the NiSi Bluetooth Remote Control. Select a base/normal shutter speed before adding a filter to the camera.
Then select your filter and the new exposure time will be calculated. Press the Start button to release the shutter for the calculated time when using the NiSi Bluetooth Remote.
Available FREE on the Apple App Store and Google Play Store.