Aperture is a
recurring setting in the composition of my photographs. I always
use the aperture priority of my camera. Speed does not matter
for the subjects I photograph and this is even more true since
the cameras are able to get into high ISO.
On most analog
cameras of the 80s, the aperture values are accessible via the
rotating ring belonging to the attached lens. This is still true
today digital cameras FUJIFILM X. On the housings modern DSLRs,
the lens is now very often devoid of an aperture ring. Just refer
to the documentation included with the device to locate the adjustment
control of the diaphragm. Ergonomically designed for NIKON D7000
as the aperture is displayed on the top LCD panel and can be
changed according to diametrically opposed knobs to trigger.
wheel acts on aperture of a key element in camera body : Iris. This is nothing more
than a circular section, placed before the window is opened more
or less, to control the amount of light that will be able to
reach the film or sensor. This component is a thin sheet of metal
or cotton, very delicate, it is better not to touch, as fragile
as the shutter, although it is more difficult to reach because
located inside the lens.
We can make several
successful shots of the same subject at different apertures since
the shutter speed is recalculated according to proper exposure.
A still subject to the horizon or on the focal plane, the differences
will be very sensitive but on a subject on a different plane,
the choice of the aperture becomes a determining factor. It is
found in the context of using a large aperture (less than or
equal to f/8) that only the subject is in focus and the background
is blurred. In contrast, the use of a smaller aperture (larger
than or equal to f/16) provides a uniform sharpness over the
entire image. This is simply the phenomenon manifestation that
is commonly called depth of field.
than f/8 (Picture A) ; Aperture larger than f/16 (Picture B)
A device is set
to infinity and diaphragm to its largest aperture, the sharpness
will be the maximum for an object at infinity and still sufficient
even on a closer shot. This depth of field limit is the hyperfocal
distance. It is calculated using the formula : H = (F x e) / f - F being the focal length ; f the relative
openness ; e tolerance sharpness expressed as a fraction of the
focal length. Just
fun to gradually close the diaphragm to gradually see the depth
of field to expand and see the nearest become net objects, one
after the other. A 50 mm lens at f / 16 allows the pictures production
with depth of field maximum : All objects are sharp.
For a very emotional
photography, never underestimate the power of an insulating aperture
for any subject (flora or portrait in these examples). In heavily
opening the diaphragm (the smallest possible values of the lens
used to f/8), you will get an insulation of the main subject
relative to a foreground and/or a deliciously blurred background.
The dosage of the blur intensity arising from the selected aperture.|