Movie Makers (Jan-Dec 1938)

179 Waves are heavier and more impressive shot in slow motion Porter Buck from R. I. Nesmith and Associates USING VARIABLE CAMERA SPEEDS This cine device appears to make you time's master Fairbanks from Black Star JACKSON M. HACKETT THERE it was, a shining new camera, resplendent in its multi speed pride. I bought ' it, paid for it and carried it home, and now it was up to me to get my money's worth. I must admit that, to begin with, I did not know much about what camera speeds could do for a movie maker. First, I read the camera instruction book and then I looked up all the other information that I could find on the subject. Finally, I was able to crystallize my ideas with the thought that camera speeds simply control time. We cannot do it in real life, but we can do it on the screen, because a camera speed slower than normal condenses time and one faster than normal expands it. For example, a speed of eight frames will compress the time required for the action by making the motion appear twice as fast as normal. O-n the other hand, a higher speed, such as thirty two frames, slows the movement in the scene and makes the time element twice as long. The next point that became obvious is that camera speeds not only affect the time element on the screen, but that they also affect the time of exposure in the camera. Since my only speed below normal was eight frames a second, or half speed, I began to explore its possibilities. It seemed to me that my chief reason for using this slow speed would be to increase exposure. Since my camera, like most others, exposes a single frame of film for a thirtieth of a second when the camera is running at the normal speed of sixteen frames, it is plain that, if the camera runs at half this speed, the exposure time would be twice normal, or one fifteenth of a second. From still camera experience, I knew that this gain in exposure would be equivalent to a diaphragm opening of one stop wider. This additional exposure is well worth having on occasion. My camera has an f/2.9 lens, and so, by using the diaphragm wide open and a camera speed of eight frames, I can obtain approximately the exposure equivalent of an f/1.9 lens. It is true that the half speed has certain disadvantages, for it doubles the speed of tlie motion of subjects on the screen, but I decided that this did not always constitute a problem. Of course, it made no difference in the case of still scenes, and, when I could control my subjects, as in the case of portrait shots, I could caution them to move very slowly. I found that my greatest use of this half speed feature occurred in indoor shots where things were more or less under my control. I have often seen references to the comedy effect that one can obtain by filming action at half speed, but I don't think that this is going to appeal to my sense of humor except possibly on rare occasions. I think that we have all seen the method used on the theatrical screen to speed action during a furiaus comedy chase. One other idea has always stuck in my mind, for, when I read it some time ago in Movie Makers, it seemed to be a very practical plan. It suggested the use of half speed for filming slowly moving objects, such as a ship leaving the dock. Such action often seems to be almost static unless one uses a means like this to increase the speed. The two important cautions that go with half speed filming are: be sure to compensate for the increased exposure and be sure to hold the camera as steady as possible. The first will A thirty two frame be taken care of easily if you remember to close down i . the diaphragm one full stop when you change the speed improves a , . r,. ° ™ ,r .,, . r ' speed indicator, lhe second possibly is an even more waterfall picture important point, for, when [Continued on page 198]