Exposure Calculator

This is a photographers tool written in (cross-browser) Javascript, simulating Aperture Priority and Shutter Priority calculations according to ISO/ASA value, scene-type and exposure compensation.

How to use

Start with opening this page, which contains the calculator.

The calculator contains 5 selectboxes:

• EV: describes the sort of scene you're trying to capture
• F-stop: aperture-value
• Speed: shutterspeed-value
• ISO: the ISO/ASA value your camera is using
• Comp: the amount of exposure compensation you're using (or when using an ND filter)

Changing any of the settings results in an update of the two boxes at the bottom of the calculator (the blue box containing the Aperture Priority result, the green box containing the Shutter Priority result) for the correct exposure.

Tip

Save the calculator to disk as a normal HTML file, and transfer it to your favorite HTML-and-Javascript-capable mobile device (PDA, mobile phone). I wrote the calculator with my mobile phone (Sony Ericsson P910i) and the mobile version of the Opera browser in mind (hence the small type and cramped layout).

Terms of use

Distribution of the calculator, and the codes within it, is allowed for non-commercial purposes. Distributed versions must always retain the included attribution. Use of the calculator is not limited to non-commercial purposes, and copying it to a mobile device for normal use will not considered to be distribution.

See also

Fred Parker's page explains in great detail how you really should be metering. My calculator is based on the ideas of the Ultimate Exposure Calculator as explained on Fred's webpage.

If you prefer an analog version of the calculator, check out the New Jiffy Calculator, which I've also used to doublecheck the results of my calculator.