This is exactly the same app as the free one. If you haven't tried that one yet please install it and take it for a spin. Afterwards if you think it is worth 3 Euros feel free to come back here and install this one.

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 1 to 3 ND filters of up to 30 stops each to the calculations handy for those long exposure photographs to blur water and clouds.

The app also includes a timer for exposures of 4 seconds or longer.

Main features:
 • aperture range from f1.0 to f360
 • shutter range from 30s to 1/16000s
 • ISO range from ISO 0.4 to ISO 3.2M
 • ND filter up to 30 stops in 1 1/2 or 1/3 stop increments
 • up to 3 stacked ND filters
 • ND filter modes: stop density ND number
 • timer for exposures of 4s or longer with alarm
 • night mode (Lollipop and above)
 • optional compensation wheel to account for reciprocity failure

Permissions:
 • control vibrator: to vibrate after the timer expires
 • read external storage: to enable selecting a custom ringtone stored on the SD card to be played when the timer expires

A review of the app is available on this blog post: http://www.craigrogers.photography/?p=2548

Note: in the Shutter settings section there is a switch tor camera type. This switch simply selects how a small set of shutter speeds around 1 second are displayed choose the one your camera adheres to. Exposure calculations work for all camera makes this switch is simply for display purposes.