Re: cds cells and such

[P3D sid herbage <sid@xxxxxxxxxx>]

P3D romney wrote:
This is because with bright light the digital timer
> begins to count when the blades are barely open and only stops when they
> are nearly closed. In dimmer light it might not gate until the blades were
> nearly open...Long ago they let shutters be 1/3 slow and still pass
> standards. Most 1/1000 second cameras were really about 1/700 sec. then. A
> 1/500 sec Compur Rapid is really 1/400 sec, and the 1/150 sec Realist
> shutter would have been called !/200 sec. 

This begs the question "to what does the shutter speed really refer?".

Is it the time from the instant the shutter starts to open to instant it
just becomes fully closed? Is it the time at the full open position? Is
it some some sort of time integral of the open area of the shutter
expressed as an equivalent time at the full open position?

I don't know, does anyone else?
-- 
    ... Sid (sid@xxxxxxxxxx)


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