Page:Popular Science Monthly Volume 89.djvu/93

This page needs to be proofread.

Details of a Remarkable Motion-Picture Camera


��The Film Cutter Ciirl

Five features distinguish Carl Akeley's camera from all existing appa- ratus. The film cutter shown at the right is used to cut a hole in the film to indicate to the de- veloper when a given series has come to an end. The hole is also used as an aperture through which the operator can stop the machine, puncture the film, and then focus to a dead accuracy on a groimd glass. Consequently, when the film is developed the perforation noti- fies the operator exactly where the stop was made. The cutter is actuated by a pull and push rod leading to the outside of the camera. One push of the rod cuts a hole in the film and brings the ground glass into position. An eye-piece attached to the film cutter enables the operator to locate the image on the ground glass and regulate the focussing and diaphragm dials

��Akeley's Woiulefl'iil liivriiliuu





��Seeing the Image

The eye-piece, as shown above, enables the photog- rapher to see the actual image being recorded on the negative — sometliing hitherto unheard of. It consists of a square metal box with a sliding end fitted with a light-proof, black velvet rim for the eye. A spring which serves to lift the eye-piece up and which closes the finding aperture by a metal stop at the same time, is pressed down when the eye rests against the rim. This gives the photographer an unobstruc- ted view of the image falling on the negative


���Eliminating Fric- tion of the Film

The film box, as shown above, consists of two telescoping shells which are locked together by a pin and slot device. The inner shell has a spring with a roller end over which the film feeds out. This roller end serves to eliminate friction and also prevents scratching while taking pictures. The spring stud of the main driving shaft locks the film box with the driving gears, which in turn rotate the film at the speed set by the op>erator


��perforations and with- drawn from them one by one so that the film is literally picked along. This gives a uniform movement and entirely eliminates all "jerkiness"


��How the Shutter Works

The shutter, illustrated above, consists of the main or outer shell of the camera containing the lens opening and a secondary shell half cut away, this latter being the shutter proper. As the secondary shell revolves over the main shell the lens opening is alternately closed and shut by that portion of the second- ary shutter which has not been cut away. The exposure efficiency is in- creased to eighty-five per cent

�� �