Nor, am I but you can very easily hit the 1/4000 limit pretty easily in bright conditions. Using an ND filter in these conditions is pretty standard
again - I do not need to deteriorate my images w/ ND filters w/o a real need and for as long as I do not need to have a longer exposure time (to have smooth waterflow surfaces) I am not going to use them... you might have a different opinion and that is OK, but you might want to imagine also a situation when you can't afford to slow the exposure w/ ND filters too, then what... but it really has nothing to do w/ loud noise from improperly designed aperture mechanism in PL25/1.4
....and is built in on cameras where it makes sense (Oly XZ1, Canon G series).
there is a difference between ND filter which was designed from the very beginning to be in the optical path and the lens which was not designed w/ it inside
then there are enough high level P&S w/o that (LX3/LX3, TL500, etc)
then the quality of their optics is low enough to pay any serious consideration
but again - it has nothing to do w/ mechanical operation of PL25/1.4... if you are suggesting it as the way to avoid the annoying sound then I might as well plug something in my ears in order not to hear it...
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