jlind@xxxxxxxxxxx writes:
<< The practical limit on a leaf shutter is about 1/500th. Shutter
speeds faster than 1/500th can have problems with producing an even
exposure across the film plane. >>
John,
I don't know what is used in the XA but.. If it is a leaf shutter
it has a circular opening so at high speeds it just has a variable F-stop as
the blade travel time becomes a significant part of the exposure time. Thus
the exposure remains even across the film plane even if it is slow. In some
small auto only cameras the diaphragm is the shutter and it only opens part
way so the travel time is less significant at small f-stops. (Thus program
mode is a good fit :small f-stop+high speed) Similarly if the shutter and
diaphragm are placed close together. The distance that the blades have to
travel in an XA is also probably much shorter than say a large format leaf
shutter that struggles to get to 1/500sec. As an aside, some cheap auto
cameras have terrible bokeh as the combined shutter/diaphragm has only two
leaves with aa approximately rectangular shaped opening.
Regards,
>>>Tim Hughes<<<
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