ExpoImaging ExpoAperture2 Manual (Imperial/Standard) - Manual (Page 17)

ExpoAperture 2 Depth-of-Field Guide Manual
V 1.0
17
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 2
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 2 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.