"Georg N.Nyman" wrote in message
...
Hi,
I would like to try to answer the original question -
shutters need to be designed such that the exposure time of each part of
the
image is more or less the same to get an evenly exposed image. [...]

And obviously, the larger the leaf shutter, the more limited the top shutter
speed. Look at the Copal #0 with 1/500th compared to the *gasp* Ilex #5
which has a (nominal) 1/50th top speed (which I find is actually closer to
1/30th).