Funny but not what im talking about and that shutter looks nothing like a
modern copal. And im not talking about what you are talking about. Im
saying this. As the shutter design fails and exposure isnt accurate. That
over exposure because of the closeness of the iris is equal failure across
the entire frame. The failure will not result in an uneven exposure just
an
inaccurate exposure.
agreed, it's really a lens or vigneting issue if there's uneven exposure
across a frame as the shape of an iris has little or nothing to do with
exposure across a frame for a leaf shutter (focal plane of course is a very
different animal). cat's eye, slit, star, blinking eye, rotary, window
blind - propeller - none of them should affect the exposure from center to
edge (well, maybe the propeller).
Andy linked:
http://www.davidhazy.org/andpph/2014-pix/2014-mechanical-shutters-1.jpg
which looks kinda like a more modern shutter illustrated here:
http://www.kern-photo.com/2013/01/why-leaf-shutter-lenses-matter/
In Andy's, I can't see the scale and am presuming it's in similar time
intervals, if this is the case then at the smallest aperture the exposure is
open from the first shot.. or all 18 frames. 18/18
wide open is only open for 4/18 intervals. that's 2/9ths of the exposure
.. meaning the first frame aperture was open 4.5 times longer than wide open
exposure.. that's not at all to say it got 4.5 times more exposure, as the
incremental exposures also added to the overall exposure - but I am not in
the frame of mind at the moment to throw myself at complex calculations to
determine the total difference. I would guess it would be more than 1/10th
of a stop difference though.
