Photographic Arrangement 2

Objective

To photograph a succession of leaps and moments of a visible object moving at a velocity exceeding 1000 fee per second.

Technique:

The equipment is set up according to the arrangement shown in the diagram below. A small object, such as a pellet, common washer or small nail is placed atop a magnetized nail, directly along the flight path of a rifle bullet and in front of the camera lens. All lights in the room are extinguished. When the gun is discharged, the bullet first pushes down the trigger wire, completing a circuit and discharging a 1/2000 second flash (a relatively slow burst of light). The bullet continues on, hitting the object from the nail and sending it tumbling at a higher velocity than the bullet. The path of the object is recorded and extends the full frame of the negative.

(Also see Background to Photographic Techniques)

Photographic Equipment

Camera: Minolta 35mm single lens reflex.
Shutter Speed: N/A. All lights are turned off and shutter is opened until after bullet is fired.
Lens: 35 mm/F 1.4 lens, protected with ultraviolet filter. A close-up tube was used to bring the camera within 4 inches of the center of the field.
Film: Kodak Recording Film ASA 1000.
Flash: Honeywell Auto/Strobonar 360 (Strobonar 360 Test and Specifications)
Flash Duration: 1/2000 of a second.
Flash Placement: Strobonar placed at 45 degree angle, 9 inches from the line of fire, on the right of the camera; that is, indirectly facing the oncoming bullet. The strobonar is covered by a mask with a 1/4 inch hole in the centre.
Backdrop: Black cardboard, set back four feet from the line of fire.


Arrangement of Equipment

Illustration of Equipment


Trigger Circuit


Trigger: The strobonar shutter cord is spliced and lengthened with an electric wire, leaving the two ends loose. One end is tied to a ground post while one strand of the other end is stretched above the post in the path of the bullet. This strand is then knocked down against the post as the bullet passes, completing the circuit and triggering the flash.