Apps in this category may contain mild or occasional cartoon, fantasy or real-life violence, as well as occasional or mild adult, sexually suggestive or horrifying content and may not be suitable for children under 9 years of age.

12+

Apps in this category may contain occasional mild indecent language, frequent or intense cartoon or real-life violence, minor or occasional adult or sexually suggestive material, and simulated gambling, and may be for children under 12 years of age.

17+

You must be at least 17 years old to access this App.

Apps in this category may contain frequent and intense offensive language; Frequent and intense cartoon, fantasy or realistic violence: frequent and intense adult, scary and sexually suggestive subjects: as well as sexual content, nudity, tobacco, alcohol and drugs, may not be suitable for children under 17 years of age.

Zone Tool Screenshots

iPhone

About Zone Tool

With this tool you can calculate your exposure and needed adjustment for development. It uses zone system theory originally invented by Ansel Adams and Fred Archer.

First decide zone of your shadows and measure the shadows. Then device highlight zone and measure the highlights. Measure these with the film ISO you are going to use. You also need to decide shutter speed in beforehand.

The app calculates exposure aperture for you and also tells if you need to shorten (N+..) or expand (N-..) your development time.

You will get best results with a spot light meter but mobile apps will probably do fine.