Canon FTb - Depth-of-Field Scale

Depth-of-Field
Scale
The
depth-of-field
scale
indicates
the range
of
subjects
which will be in
sharp focus on
the
film.
In this
case, the
depth-of-field behind
of
the subject
is
deeper than
in front
of
su
bject. Th is
ra n
ge
wi ll
va
ry with the
f
ollowin
g
f
actors
:
The depth-of
-f
ield
will
be
deeper,
the
larger the f/stop
num-
ber,
the f urther the
distance of the
subject,
andf
or the
shorter
the focal
length
of the lens. The depth-of-field
will
be
shallower, the
smaller
the f/stop number, the nearer
the
distance
of the
subject, and/or the
longer the
focal
length
of
the lens.
For example, if
the lens is 50mm
and
the subject has
been
focused
at a
distance of
3m
(10'),
with an
f
/A
aperture
opening
read
off
from
both indexes on either
side
of
the
in-
dicator
(orange
linel,
the approximate depth-of-field
is
from
2.3m
(8'l
to
4.3m
lL4'1.
lf
the
aperture
is
closed down to
f
/
L6,
the'picture
will
be-
come
sharp
when the
subject
is between 1.9m
(6')
to
7.6m
125'l-
from
the camera. This range
will
vary
with
the select-
ed
f/stop.
I
In
the case
of Canon
FD
lenses,
you
can
see
the actual
sharpness
through
the
viewfinder
by
pressing
the stopped'
down
functioning
lever.
r
Although
air
bubbles
may
sometimes
be
seen
in a
lens,
they do
not
affect
the
resolution
power
or the sharpness
of
the
picture.
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