The first requisites for moving objects are a green baize apron and a wide vocabulary: from then in it is a question of you versus the object. This series happen to be an example of prolonged indoor work, but the same general principles apply outdoors, although the exposure will probably have to to be cut down to conform to police regulations.

A contemporary authority, who would deem to be interested in rather faster subjects than I am, has the following comments to make: "... That wretched phrase "' Instantaneous ' gets in its fell work every-"where, and I must warn the beginner "against a very common failure, that of "firing at objects which are in reality moving "at too great a speed.

"The following table will show at once "what can be done and what should be left "undone:-

"Man walking 5 miles per hour.

"Vessel travelling at 20 knots per hour. "Finish of Cycle Race 30 miles per hour. "Express Train 50 miles per hour.

"To find the distance the object will move "upon the plate is it only necessary to multi-"ply the focus of the lens in inches by the "distance moved by the object in the second, "then divide the result by distance of the "object (from the lens) in inches, and "finally divide by the speed of the shutter. "For example, I will take the finish of a "cycle race under ordinary camera condi-"tions. The lens of 5 1/2-inch focus, the "shutter working at the 1/30th of a second, " and the object 10 feet away, the calculation would come out "5 1/2 x 44=242/120=2 inches per second " Now as the shutter works at the 1/30th of a second, the movement upon the plate " would be a fraction over 3/30th or 1, 16th of an inch. The resulting photograph " would be a curiosity.

"In the above example the conditions are those of the majority of hand-cameras, " as although the shutters are often put down as working at the 1/100th of a second, "or at even greater speed, considerable discount must be allowed upon these " statements. The limit of movement upon the plate, if anything like a sharp " image is desired, is the 1/100th of an inch. So that by working backwards we " can find the shutter speed required or the distance from the object actually "necessary. The speed would have to be increased to the 1 200th of a second, "or with the same shutter (working at 1 30th) the camera would have to be "2,106 feet 10 inches from the object, which is too far to walk. "I trust these tables will prevent the beginner from wasting plates in the absurd "fashion that I have seen done on many occasions. Of course the movement is "calculated full broadside on, an object coming towards or receding from the "camera is a much easier task."

A glaring example of "Foot light Exposure".