The Sunny 16 rule is a handy rule of thumb in outdoor daylight photography; the rule estimates the required daylight Exposure Value without using a light meter.

This rule evolves around three concepts:

1) Incident light (as opposed to reflected light); an advantage for `difficult' subjects

2) The different lighting conditions in outdoor photography (sunny, slight overcast, overcast, heavy overcast, and open shade/sunset)

3) The relatively fixed exposure value for daylight under these conditions


What the rule does NOT prescribe are the actual camera settings (aperture, ISO and shutter speed) that you can use, as long as the combination of manual camera settings lead to an equivalent exposure value as specified by the rule.


And this is exactly where the Sunny 16 Calculator app comes in: it lets you

a) change settings for aperture, ISO and shutter speed, and

b) balance out these settings to achieve a correct exposure in accordance with Sunny 16.


The calculator supports the balancing process by indicating the resulting overall exposure value in stops RELATIVE to the rule for a selected lighting condition. As explained below, the calculator can also be used in combination with filters.

The calculator can also be used as a `training device', where you first guess the required combination of settings for balance, and subsequently check these with the calculator.


Explanation for the calculator screen, from top to bottom:

A) Select a lighting condition. Based on the lighting condition, the calculator automatically selects the aperture, ISO and shutter speed in accordance with the Sunny 16 rule.

B) The number display indicates whether the selected settings are in balance (indicated by 0), or whether a correction in the settings is necessary (indicated by a negative number for under exposure, of a positive number for over exposure)

C) If you want to change settings for aperture, ISO or shutter speed, you can select this in the switch just below the number display. Of course changing settings will lead to the number display increasing or decreasing; this exposure offset needs to be balanced out by using (a combination of) the other settings, until the displayed number becomes 0 again. If a filter is used, the number should be made equal to the exposure compensation value of the filter. The switch itself continuously displays the selected values for aperture, ISO or shutter speed.

D) The circular controls for aperture, ISO and/or shutter speed are displayed below (when the screen is in `portrait mode') or to the right (in `landscape mode'). You can change the settings for the circular control either by tapping on the control or by moving the pointer.


Further characteristics:

- No in-app purchases
- No account, no login
- No advertisements