47
46
EXPOSURE MODE
Selecting the exposure control mode means deciding if you
want the shutter speed and/or lens aperture to be set
automatically or manually.
The Nikon F70/F70
D
camera offers two types of programmed
auto exposure modes, Auto-Multi Program (
A
) and Vari-
Program (
S
), as well as Shutter-Priority Auto (
F
), Aperture-
Priority Auto (
D
), and Manual (
G
) exposure modes.
SELECTING EXPOSURE MODE
Light reaching the film is controlled by shutter speed and lens
aperture. The proper combination results in a correct exposure.
Shutter speed and lens aperture settings are based on the ISO
speed set for the film in use and the operation of the camera’s
exposure control system.
The relationship between aperture and shutter speed is as
follows: One change in shutter speed either doubles or halves
the amount of light transmitted. For example, a shutter speed
of 1/500 sec. passes half the light of 1/250 and double the light
of 1/1000 sec. The aperture f/8 passes half the light of f/5.6
and double the light of f/11. If the correct exposure for a scene
is 1/500 at f/8, then we can also select 1/250 at f/11 or 1/1000
at f/5.6 and achieve the same exposure results, and so on.
Programmed Auto exposure modes (
A
/
S
)
With the F70/F70
D
’s microcomputer choosing the combination
of shutter speed and aperture automatically, you can
concentrate on picture composition, without worrying about
exposure.
Note that programmed auto exposure modes operate only with
Nikon lenses that have a built-in CPU (AF Nikkor and AI-P
Nikkor lenses).
When
S
for Vari-Program is selected, you have a choice of
eight options: (1) Portrait Program, (2) Hyperfocal Program, (3)
Landscape Program, (4) Close-Up Program, (5) Sport Program,
(6) Silhouette Program, (7) Night Scene Program and (8) Motion
Effect Program.
For details about Vari-Program, see pages 61 to 67.
Auto-Multi Program (
A
) is used for most common picture-taking
situations. The chart at right shows the shutter speed/aperture
combinations for Auto-Multi Program that are selected at each
EV (exposure value) brightness level.
In Programmed Auto exposure mode, you can use the Flexible
Program function to temporarily shift an automatically selected
shutter speed/aperture combination and obtain the desired
shutter speed/aperture (p. 51).
Program chart of Auto-Multi Program
To check shutter speed and aperture values, follow either the
black or red line to where it intersects the diagonal line.
With 50mm f/1.4
With 180mm f/2.8
With 300mmf/4
With AF Zoom-Nikkor 35-80mm f/4-5.6D at
35mm and 80mm focal length settings.
High-brightness limit for Matrix Metering
-4
-3
12
-2
-1
0
1
2
3
4
5
6
7
8
9
10
11
-5
f/1.4
2
2.8
4
5.6
8
11
16
22
32
30" 15" 8"
4"
2"
1"
2
4
8
15 30 60 125 250 500 1000 2000 4000
23
22
21
20
19
18
17
16
15
14
13
16
3
1
EV
sec.
-4
-3
12
-2
-1
0
1
2
3
4
5
6
7
8
9
10
11
-5
2
2.8
4
5.6
8
11
16
22
32
30" 15" 8"
4"
2"
1"
2
4
8
15 30 60 125 250 500 1000 2000 4000
23
22
21
20
19
18
17
16
15
14
13
16
3
1
f/1.4
EV
sec.
(ISO 100)
F70D I/MêÊçsâ¸í˘ 03.1.16 5:33 PM Page 46
