ExpoImaging Medium Format Film User Manual

Expoaperture depth of field guide

V. 01 SEP 05

ExpoAperture Depth of Field Guide

MEDIUM FORMAT FILM INSTRUCTIONS

120/220 film square format

Using the ExpoAperture Depth of Field Guide with medium format film (120/220) is very simple;
you either multiply or divide the number of zones by two as you switch from one side of the

Guide to the other. If starting on the front of the Guide multiply the number of zones by two and

then use that number of zones on the Zone Dial. If starting on the Zone Dial divide the number

of zones by two and then use that number of zones on the front of the Guide.

Example 1: Determine the appropriate aperture setting and focal point to
produce a given depth of field, such as 7½ feet to infinity, using a 100mm
focal length lens.

1.a On the Zone dial (the back of the

Depth of Field Guide) determine how

many zones need to be in focus.

For 7½ to infinity to be in focus,

four (4) zones are required.

1.b Determine the mid-point of the zones

to obtain the required focal point.

The mid-point is 15 feet

Focus your lens at 15 feet

1.c Divide the number of zones by two

(2).

The number of zones is now 2

1.d On the front of the Depth of Field

Guide set the dial to the actual focal

length of your lens.

100mm

1.e Read the required aperture setting

above the number of zones

determined in step 1.c above.

Using 2 focus zones

The required aperture is f32