Download the Mobile Zone Calculator


This is an idea that I have had in the back of my mind for some time; but it doesn’t make much sense unless it is mobile.


Run this document as a smart phone app!  Specific instructions on how to do it on Android here

Tested and works in the following mobile browsers:  Dolphin Mini and HD, xScope, Angel, Miren, Boat Browser Mini, Skyfire, and Opera Mobile.  Works with some quirks in Opera Mini as the script is executed at the server.  Works on the desktop in Firefox 5, IE 8, Safari 5, Opera 10, and Google Chrome 13.  Does not work properly in IE 7 due to a CSS bug in that browser; but remember, this is a mobile app.

The Mobile Zone Calculator helps you use your spotmeter, either in your camera or handheld, to make zone placements, and determine a range of multiple exposures if necessary.  It can also convert your camera’s meter readings into actual exposure values as if you were using a handheld meter.

If you are using digital or transparencies, the suggested workflow would be:
• Meter a textured highlight and place it on zone VII to prevent overexposure.
• Then meter a detailed shadow and see if it falls within the range of your medium.  If you are shooting RAW, this would be in the neighborhood of zones O-II; for .jpg or transparencies, it would be more like zones II-III.

If you are using negatives, either black-and-white or color, the suggested workflow would be:
• Meter a detailed shadow and place it on zone III to prevent underexposure.
• Then meter a textured highlight.  There is some latitude here; the expected value for this is zone VIII, but most modern films can record data past zone X.

The meter 2 fall is based on meter 1.  If meter 2 falls outside the available range, place it where you want it, and the two indicated exposures will represent a range of exposures that will capture all of your values.  Make exposures at appropriate intervals across the range.

In camera mode, if you specify the ISO speed, the actual exposure value (EV) will be displayed along with the shutter speed and aperture.