Handbook of High Speed Photography - IET Labs, Inc.

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section 4 STILL PHOTOGRAPHY 4.1 GENERAL. The taking of a high-speed photograph, which we will define in this book as the photographing of an event which occurs at a rate (lin ear velocity, angular velocity, growth rate, etc.)faster than one hundred feet per second is made difficult by the inherentslowness of two things: the camera and the photographer. The slowness of the camera obliges the photographer to seek a fast substitute for the shutter, and the slow ness of the photographer necessitates the use of some sort of automatic timing device for the coordination of subject and camera. Such devices will be discussed in detail in Section 5. The special problems en countered with the camera-light-film system in high-speed photography are discussed below. 4.2 THE OUTPUT CHARACTERISTICS OF GENERAL RADIO STROBOSCOPES. A xenon lamp is usually employed in stroboscopes because of its high efficiency in converting electrical energy into light. The flash is defined by the light-vs-time curve in Figure 4-1, and the spectral distribution plot in Figure 4-2. The flash duration used in the specifi cations is defined as the time during which the light intensity is greater than one-third of the peak value. Most of the light is emitted during this period, and little of the total light is contained in the lingering "afterglow" or "tail". The light produced by the lamp is concentrated by a reflector. The apparent source of the light beam thrown by the General Radio Types 1531, 1538, and 1539 Stroboscopes is 18 inches behind the re flector front. The beam-angle of this source is 10°, so that a narrow cone of light is produced by the flash. Outside this 10° cone the light intensity falls off sharply, so that the area of reasonably constant il lumination is not large. Since a variation of 2:1 in incident light in tensity corresponds to an exposure increment of approximately one f-stop setting, the diameter of the 10° beam cone provides a good ap proximation to the useful illumination area of the Strobotac when the 25
100 — OF In CENT (PERO TENSITY 1 J \^_1538 w/1538-P4: 8.0ms—1540: 10 -15ms 2o N. 3.0ms 0.8- 1539: 1531, 1538: i25" 3.0ms 0.5- O X TIME- Figure 4-la. Output light intensity vs time for GENERAL RADIO stroboscopes. HHSP-6 Figure 4-lb. Integrated light of the pulse of Figure 4-la as a function of time. Note that most of the total light to which the film responds is produced during the interval that defines flash duration. 26
Page 1 and 2: TTT TTT' 4M44|Ht|MHM4 < Q. \ X t J*
Page 3 and 4: TABLE OF CONTENTS ACKNOWLEDGEMENT F
Page 5 and 6: FOREWORD When I first heard about h
Page 7 and 8: Figure 1-2. A .22-calibre rifle bul
Page 9 and 10: Figure 1-4. Multiple-flash analysis
Page 11 and 12: From the measured distance between
Page 13 and 14: 1.3 USING THE STROBOSCOPE WITH MOVI
Page 15 and 16: TYPE OF APPLICATION REQUIREMENTS Si
Page 17 and 18: 2.3 FLASH INTENSITY VERSUS DURATION
Page 19 and 20: ..«""*&&. 1 A Figure 2-2. Study of
Page 21 and 22: section 3 GENERAL RADIO STROBOSCOPE
Page 23 and 24: Figure 3-2. Using the Stroboslave t
Page 25 and 26: 3.2.2 EXTERNAL TRIGGERING. The Stro
Page 27 and 28: The flashing rate of the 1538 Strob
Page 29: Type 1540-P4 Oscillator/Delay Unit.
Page 33 and 34: XENON FLASHTUBE (STROBOTAC) 7000 AN
Page 35 and 36: 4.4 GUIDE NUMBER CHART. A guide num
Page 37 and 38: At extremely short camera-subject d
Page 39 and 40: the relative position of these mark
Page 41 and 42: Figure 4-8. Shock-wave photography
Page 43 and 44: 4.8 OPERATION OF CAMERA SHUTTERS AT
Page 45 and 46: The camera should not be loaded wit
Page 47 and 48: 5.2.2 MECHANICAL CONTACTS. Mechanic
Page 49 and 50: 5.2.3 OPTICAL PICKUP. The optical p
Page 51 and 52: chronization. For instance, the mot
Page 53 and 54: mine the proper attachment of the l
Page 55 and 56: must be set to "Bulb", the Strobota
Page 57 and 58: 5.3.2 OTHER SIGNAL PROCESSING DEVIC
Page 59 and 60: applications require the burst to b
Page 61 and 62: made with the same camera without r
Page 63 and 64: section 6 MOTION-PICTURE PHOTOGRAPH
Page 65 and 66: The subject image will appear to mo
Page 67 and 68: Section 6.4. Photo- and reluctance-
Page 69 and 70: BLADE HAS JUST CLEARED WINDOW TO ST
Page 71 and 72: HIGH-SPEED PHOTOGRAPHY has many use
Page 73 and 74: Use of dry-ice pucks on smooth, lev
Page 75 and 76: Spindle on a textile spinning frame
Page 77 and 78: Combustion study of twin, oscil lat
Page 79 and 80: Ropidly moving bubbles of hu man bl
Page 81 and 82:
Spray pattern of diesel fuelinjecti
Page 83 and 84:
\ Multiple-flash of golf ball just
Page 85 and 86:
A pulsating, solenoid-actuated wate
Page 87 and 88:
Edgerton, Harold E., "Shock-Wave Ph
Page 89 and 90:
INDEX Acceleration 5, 79 Accuracy 1
Page 91 and 92:
Type1531-AB STROBOTAC* ELECTRONIC S
Page 93 and 94:
Type 1538-A STROBOTAC electronic st
Page 95 and 96:
Type 1531-P2 FLASH DELAY synchroniz
Page 97:
Type 1541 MULTIFLASH GENERATOR a tr
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