ExpoImaging ExpoAperture2 Manual (Imperial/Standard) User Manual

Page 17

ExpoAperture

Depth-of-Field Guide Manual

V 1.0

EXAMPLE:

A photographer is using a Medium Format film camera that produces a 6 x 4.5 cm image
and an 85mm lens stopped down to f/22. What is the hyperfocal distance for the

photographer’s shot?

STEP 1 –
Set the Focus Length Dial to the correct format or

desired circle-of-confusion that you wish to use, in this

case, 6 x 4.5 or 52 microns.

STEP 2 –

Rotate the Focus Zone Dial to expose the focal length

of the lens you are using through the small window

labeled “FL – mm,” here, 85mm.

STEP 3 –

Note the number of Focus Zones under the aperture

(f/stop) to which you have your camera set. In this case, the
number 3 (representing three focus zones) is under f/22.

STEP 4 –

Turn the guide over. On the Distance Dial start at infinity
(∞) and going in a counter-clockwise direction count out the

number of Focus Zones determined in step 3 (3 zones),

noting the distance at which you end up, 10’.

STEP 5 –

Determine the mid-point of the distance you just counted out, in this case, halfway between

10’ and the ∞ symbol is 20’. This is the hyperfocal distance. When you focus your camera

at the hyperfocal distance of 20’, everything from 10’ to infinity will be in focus.

2.H - Setting Apertures for Lenses with Focal Lengths Greater than 135mm

Shooting with lenses of focal lengths greater than 135mm using the Standard ExpoAperture

Depth of Field Guide requires a simple calculation to determine the required aperture setting

for your desired depth-of-field. Note that if you will frequently be shooting with lenses with

greater than 135mm focal length, ExpoImaging also makes a Telephoto version of the

ExpoAperture

Guide which does not require additional calculations for these focal lengths.

First, find the smallest divisor of the actual focal length used that will result in a focal

length that falls on the Depth-of-Field Guide (in other words, a focal length less than

135mm). For example, if shooting with a 300mm focal length, the number to use is 3, since
300mm divided by 3 is 100mm, which is less than the maximum Aperture Guide focal

length of 135mm. Dividing 300mm by 2 will not work in this example, because 150mm is

greater than 135mm and does not fall within the focal length range available on the Aperture

Guide.