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:
 • calculates Shutter, Aperture or ISO
 • aperture range from f1.0 to f360
 • shutter range from 480s to 1/16,000s
 • 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
 • bulb mode (up to 24h)
 • reverse filter search mode
 • ND filter calibration mode
 • timer for exposures of 4s or longer with alarm
 • night mode with 4 overlay colors
 • optional compensation wheel to account for reciprocity failure
 • unlimited number of presets
 • free and ad free
 • privacy - the app does not collect any data and does not have Internet access

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.