International photographer (Jan-Dec 1935)
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November, 1935
The INTERNATIONAL PHOTOGRAPHER
THE DESIRABILITY OF INCREASING THE MAXIMUM SHUTTER OPENING ON MOTION PICTURE CAMERAS
By Fred Westerberg
Thirty-one
The two tables on shutter operation shown below have been designed to show among other things the desirability under present conditions of increasing the maximum shutter opening on standard motion picture cameras from the present value of 170° to a value of 240°.
Take for instance the matter of compensating for changes in the camera speed. What could be simpler than the values given in the first column? 240° at 24 speed, 160° at 16 speed, 120° at 12 speed, etc. This simplicity existed at one time when the normal camera speed was only 16 pictures per second. Now that the camera speed has been increased to 24 pictures per second the logical development is for the shutter opening to be increased in proportion.
The same thing is true from the standpoint of exposure. In order to compensate for the increase in camera speed the lens stop under present conditions has to be increased for example
from F3.5 to F2.8, thus nullifying to a great extent the gains that have been made in the way of faster lenses. Increasing the shutter to 240° simply means that an exposure time in the neighborhood of l/35th of a second will be maintained as in the days of silent pictures.
The change to a larger shutter opening would be of benefit in still another direction. The interval between exposures would be decreased thereby tending to give smoother action on the screen.
Camera manufacturers are undoubtedly aware of the advantages in increasing the maximum shutter opening and would have made the change before now if the problem was merely one of altering existing equipment.
The knowledge however that certain cameras do exist with larger shutter openings and that cameramen desire this feature should serve as a stimulus to further efforts on the part of those manufacturers whose cameras are in general use.
CAMERA SPEED— SHUTTER COMPENSATION
SHUTTER VALUES REUIRED TO COMPENSATE FOR CHANCES IN THE CAMERA SPEED
SHUTTER OPENING— EXPOSURE TIME
EXPOSURE TIME AND THE INTERVAL BETWEEN EXPOSURES OBTAINED AT VARIOUS DECREES OF SHUTTER OPENING
Camera Speed
in Pictures
Per Second
EXPOSURE
TIME IN
FRACTIONS OF
A SECOND
1/36
1/48
1/72
1/144 il 1/38
1/51
1/96
REQUI
SHU ?ED TO
TTER OPENING IN DECREES MAINTAIN CONSTANT EXPOSURE TIME
96
240
72
180
64
160
240
48
240
120
180
36
180
90
135
2,2
240
160
80
120
24
240
180
120
60
230
170
90
22
220
165
110
55
211
156
83
20
200
ISO
100
50
192
142
75
18
180
135
90
45
173
128
68
16
160
120
80
40
153
113
60
14
140
105
70
35
134
99
53
12
120
90
60
30
115
85
45
10
100
75
50
25
96
71
38
8
80
60
40
20
77
57
30
6
60
45
30
15
58
43
23
4
40
30
20
10
38
28
15
3
30
23
15
8
29
21
12
2
20
15
10
5
19
14
8
1
10
8
5
3
1(1
7
4
Shutter Opening
in Degrees
Shutter Interval Between Exposures In Degrees
Relative Interval Between Exposures Compared
to
Exposure
Time
IN
CAMERA SPEED PICTURES PER SECOND
24
1
6
Exposure Time
Interval Between Exposures
Exposure Time
Interval Between Exposures
27(1
90
.33
1/32
1/96
1/21.4
1/64
260
250
100
.38
1/33
1/87
1 22.1
1/58
110
.43
1/35
1/78
1/23
1/52
240
120
.50
1/36
1/72
1/24
1/48
230
130
.56
1/38
1/66
1/25
1/44
220
140
.64
1/39
1/62
1/26
1/41
210
150
.71
1/41
1/58
1/27.5
1/38.5
200
160
.80
1/43
1/54
1/29
1/36
190
170
.90
1/46
1/51
1/30.4
1/34
18(1
180
1.00
1/48
1/48
1/32
1/32
17(1
190
1.12
1/51
1/46
1/34
1/30.4
160
200
1.25
1/54
1/43
1/36
1/29
150
210
1.40
1/58
1/41
1/38.5
1/27.5
140
220
1.57
1/62
1/39
1/41
1/26
130
230
1.77
1/66
1/38
1 44
1/25
120
240
2.0
1/72
1/36
1/48
1/24
110
250
2.3
1/78
1/35
1/52
1/23
100
260
2.6
1/87
1/33
1/58
1/22.1
90
270
3.0
1/96
1/32
1/64
1/21.4
80
280
3.5
1/108
1/31
1/72
1 20.6
70
290
4.1
1/124
1/30
1/82
1/19.8
60
300
5.0
1/144
1/29
1/96
1/19.2
50
310
6.2
1/173
1/28
1/115
1/18.6
40
320
8
1/216
1 11
1/144
1/1S.0
30
330
11
1/288
1/26.2
1/192
1 17.4
20
340
17
1/432
1/25.5
1/288
1/16.9
15
345
23
1/576
1 25
1/384
1/16.7
10
350
35
1/864
1/24.7
1/576
1/16.4
5
355
71
1/1728
1/24.4
1/1152
1/16.2
Lighting Problems of the Commercial Motion Picture Producer
(Continued
equipment in the lighting field that is doing much to lessen the lighting "headaches" in the business motion picture industry.
Chief among the benefactors of us commercial fellows is Art Reeves, whose "Reeves Lite" has helped us out of many a tight hole. And that can be taken literally, too, because the "Reeves Lite," constructed as it is of an extremely lightweight material, can be handled with comparative ease, and banks of them can be placed in nooks and corners that would be impossible to cover with the larger type of equipment. The style of reflector used permits, with ordinary photoflood globes, the pouring of a sufficient quantity of light to meet the requirements of any ordinary scene, and in many cases extraordinary scenes.
Let me cite a specific instance: We recently completed the filming of a four-reel dialogue dealer service talking motion picture that required the lighting of a grocery store set. Our working space was of such limited proportions that at best we would have been able to crowd in say two or three ordinary studio size
Please mention The International Photog
from Page 3)
"inkys." These would hardly have been sufficient for our requirements. We used the "Reeves Lite" instead and with no trouble at all placed twenty-four of them on the scene.
Due to the ingenuity of Cecil Wright, the cameraman, in directing the placing of these lights, our photographic results were satisfactory in every respect. We were able to get what you might really call major studio quality in our lighting.
We were able to get back lighting, top lighting, direct lighting and even in some cases were enabled to convert some of these lamps to the purposes of a "baby" spot.
What more could any commercial producer ask?
As the old bromide goes, "The proof of the pudding is in the eating," which we might paraphrase into "The proof of the lighting is in the picture," and we got that proof in highly favorable comments from the customer who pays the bill when he saw his picture projected on the screen. And to us, that rhap — that billpaying customer — is the ccurt of last resort.
rapher when corresponding with advertisers.