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Some may remember that the RPS Historical Group is organising
a re-enactment of the trotting pony exercise, as part of the marking of the
centenary of Muybridge's death in Kingston upon Thames.
The re-enactment, using 20 or so 10x8 field cameras, with
standard lenses with their shutters on 'time', will be at Ham Polo Club. We
have designed a guillotine shutter to go in front of the lens. Our mock up, made
of sheet zinc, works. What we have to decide is the width of the slot in
the guillotine blade.
Basic arithmetic suggests that an exposure of 100th of a
second would be obtained if the slot were approximately 1/100th of 32 feet or 3.84 inches with a slot of 1.94 inches
giving a speed of 200th of a second. These figures are based on the assumption
of a body falling at an acceleration of 32 feet per second per second. There is
not going to be much acceleration in a fall of two or three inches.
This is all a bit of fun, but does anyone have any reason to
doubt this arithmetic ? Or, for that matter, suggestions as to the quality of
cotton needed to activate the guillotine when it breasted by the
trotting horse.
The Muybridge Conference will be in November. Also do not
forget APIS 2004 in Scotland in September. Further details at www.hands-on-pictures.com
Terry
Terry King
FRPS
RPS Historical Group (Chairman) www.hands-on-pictures.com/ Moderated Discussion Group Post message: artaltphot@xxxxxxxxxxxxxxxxx Subscribe: artaltphot-subscribe@xxxxxxxxxxxxxxxxx Unsubscribe: artaltphot-unsubscribe@xxxxxxxxxxxxxxxxx 1. An excellent thing is as rare as it is difficult.(Spinoza) 2. A man's reach should be beyond his grasp or what's a heaven for.(Browning) 3. Frustra fit per plura quod potest fieri per pauciora.(Occam's razor or 'Keep it simple!'). 4. Nullius in Verba (Horace), 'Take no man's word for it' (motto of the Royal Society). 5. If ignorance is bliss, why are not more people happy ? (anon) |
