>
> Duncan McFadyean wrote:
> >
> > Using a video camera to check tacho. accuracy is supposed to work very
> > well. This is on the basis that the shutter speed in a video camera is
> > timed at 1/500 sec. ...
>
> Careful, do not assume all have 1/500th second shutter speed. According
> to the July 1997 catalog from B&H Photo/Video in New York (also online
> at www.bhphotovideo.com), all new Sony Video Cameras have multiple
> shutter speeds, and Panasonic PV-A207 has variable speeds between
> 1/100th and 1/10,000th of a second. Descriptions of some other brands of
> video cameras mention "Sports mode", which is a term used to describe
> one of the Sony shutter speed settings.
>
Calibrating the engine with a videocamera does not rely on shutterspeed
but on frames per second, which is 25 if i'm right. The shutterspeed is
the time the shutter is 'opened' to catch one frame. A fast shutterspeed
is usefull to get a sharp picture of the propelor blades.
Bart Jan
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