Photographic Arrangement 1

Objective

To photograph objects moving at velocites exceeding 1000 feet per second during a strobe flash of no longer than 1/70,000 of a 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 1/70,000 second flash.

(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 B&W; ASA 125.
Flash: Honeywell Auto/Strobonar 360 (Strobonar 360 Test and Specifications)
Flash Duration: 1/70,000 of a second.
Flash Placement: Alongside lens tube on the left.
Backdrop: White cardboard (important) set back 4.5 inches from line of bullet path.


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.