ExpoImaging ExpoAperture - Manual (Page 18)

18
Example: Given a 35mm Camera, 200mm Focal
Length, and a Depth-of-Field of 120’ to infinity.
Step 1 - Divide the focal length of the lens you are using by
2 and set your Depth-of-Field Guide to the resulting focal
length.
200mm divided by 2 = 100mm. Set the focal length on the
Depth-of-Field Guide to 100mm.