Minolta XG-M - Page 11

17
hP oroper ASA indication appears centered m
v>o film soeed window and locks in that posi-
inn when the Hng is released. Marks between
.umbered graduations indicate ASA numbers as
hov^^ in the ASA/DIN conversion table below.
Around the ASA/DIN
convenient frame that can be used to k^P
memos handy with the camera. It is just ^e
right size to hold the film-box end, which can
= .t-Un -Film in use.
ASA
12
25
50
100
DIN
12
16
13
20
14
15
32
16
40
17
18
64
19
80
20
21
125
22
160
23
200
24
•
250
25
•
320
26
400
27
•
500
28
•
640
29
800
30
•
1000
31
•
1250
32
1600
33
•
2000
34
•
2500
35
3200
36
asa/din conversion table
A convenient table for
ASA film-speed ratings is located on the back
coyer of the camera.
18
EXPOSURE-COIMTROL FU^^DAMEIMTALS
The two camera exposure-control settings
are lens opening (aperture) and shutter speed.
The size of the aperture determines the
volume of light reaching the film from a
given subject and lighting. The shutter speed
determines the length of time this light acts
upon the film. Apertures are expressed in
f-numbers, which are larger for small openings
and vice versa (e.g., f/16 represents a small
opening, f/2 a large one). Shutter speeds are
expressed in seconds or fractions thereof, which
are generally the reciprocals of the numbers
shown on shutter-speed scales (e.g. 60 = 1 /60
sec., and 2 = 1/2 sec.). At usual apertures, each
f-number setting (e.g., f/8) lets in twice" as
much light as the next numerically larger one
(f/11) and half as much as the next smaller
{f/5.6). Similarly, each shutter speed (e.g., 1/60
sec.) allows light to strike the film twice as long
as the next higher speed (1/125) and half as
(f/2.8 at 1/125 sec.)