3-21. What is the primary function of the camera  shutter? 1. To control the duration of exposure 2. To  control  subject  movement 3. Both 1 and 2 above 4. To control depth of field 3-22. When increasing the camera shutter speed, you must take what action to expose  the  film  properly? 1. Close down the aperture 2. Open up the aperture 3. Add an ND filter 4. Change  the  film-speed setting to a higher number 3-23. What sacrifice is made when you increase  the  camera  shutter  speed? 1. Camera movement is  more  apparent 2. A shorter focal-length lens must be used 3. Some depth of field is lost 4. Image  sharpness 3-24. You  must  stop  subject  motion  but cannot afford to loose depth of field. Which  of  the  following actions  should  you  take? 1. Select  a  faster  film 2. Increase  the  camera- to-subject  distance 3. Select  a  shorter  focal- length lens 4. All of the above 3-25. A shutter speed of 1/250 second is required to freeze image motion acceptably. Which  of  the  following shutter speeds can also be used to record the same image motion? 1. 1/30 2. 1/60 3. 1/125 4. 1/500 19 3-26. When handholding a camera with a 100mm lens, what is the slowest shutter speed you should use? 1. 1/30 2. 1/60 3. 1/125 4. 1/250 3-27. When  you  are  photographing  a  moving object, which, if any, of the following  shutter  speeds  stops image  motion? 1. 1/250 2. 1/500 3. 1/1000 4. None of the above 3-28. Which  of  the  following  factors limits the time the image is allowed  to  move  across  the  film plane? 1. The  interval  of  exposure 2. The direction of subject movement 3. Subject  speed 4. Lens focal length Figure 3A IN  ANSWERING  QUESTION  3-29,  REFER  TO FIGURE  3A.