ExpoImaging ExpoAperture2 Manual (Imperial/Standard) - Manual (Page 5)

ExpoAperture 2 Depth-of-Field Guide Manual
V 1.0
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Hyperfocal distance – In landscape photography in particular, photographers want as much of
the picture in sharp focus as possible. In the 1920s, such notables as Ansel Adams and
Edward Weston, along with several other photographers of the time, started the "Group
f64" which was dedicated to making photographs as sharp as possible throughout. The
group met only a few times and held only three shows, the first at the de Young Memorial
Museum in San Francisco. The term f64 evidentially arose from the smallest aperture setting
marked on large format lenses of the time, associating the use of this aperture with the
sharp, clear pictures prized by the group.
The group’s choice of f64 was symbolic, however, to the extent that the smallest aperture
does not always provide the largest depth-of-field. Instead, focusing your lens on the
hyperfocal distance with the correct aperture, you will maximize depth-of-field in your
image. The hyperfocal distance is the distance setting at a given aperture and focal length
that creates the most depth-of-field. The ExpoAperture Guide provides the ability to
determine hyperfocal distances (see Section 2.G, “Determining Hyperfocal Distances.”)
A photographer who is unaware of how selective focus can be put to use in composing an
image is likely to select any lens, shutter speed and aperture setting that will produce a good
exposure. While this approach may be necessary in some circumstances, skilled
photographers will never take a photograph without first deciding which areas of a scene
they wish to be in sharp focus and which ones should not. Although the extent to which
selective focus is used or is not used in a particular image is a creative decision,
implementation is a technical matter accomplished by controlling a lens' depth-of-field.
1.B - Controlling Depth of Field
The optical characteristics of lenses that permit control over depth-of-field are lens aperture,
lens focal length, and focusing distance. These characteristics are the primary variables in
depth-of-field calculations. It is not necessary to understand depth-of-field formulas in
order to understand the relationships these variables have with one another. This
understanding is enough to allow you to use depth-of-field creatively. The accompanying
ExpoAperture 2 Depth-Of-Field Guide will do the calculations for you, allowing you to
concentrate on the aesthetic elements of your image.
Aperture – Every serious photographer understands that the size of the lens diaphragm
(aperture setting) affects depth-of-field. The ability to set the aperture is present in all but
the simplest cameras. Specifically, the smaller the aperture (the larger the f/stop number),
the more depth-of- field obtained, and, conversely, the larger the aperture setting (the
smaller the f- stop number), the less depth-of-field obtained. In most situations, the f/stop
selected for use will noticeably affect the image's appearance in the final photograph.
Focal length – The longer the focal length used, the less depth-of-field obtained, and,
conversely, the shorter the focal length used, the more depth-of- field obtained. Like the
f/stop selection, the selection of a different focal length will affect the image's appearance in
the final print.