On 2018-03-15 6:13 PM, Jan Steinman via olympus wrote:
From: Moose <olymoose@xxxxxxxxx>
On 3/13/2018 1:35 PM, John Hudson wrote:
Are there any opinions about the use of variable neutral density filters,
I read all that stuff, and bought a Hoya variable, so it is probably true that
it was the apparent sweet spot between
quality and cost in my reading of reviews. I also have fixed NDs in a couple of
sizes and densities.
I have them to allow me to retain all the aberrations of my old/fast/weird MF
lenses by keeping them wide open without
astronomical/impossible shutter speeds, so qualities such as perfect glass
aren't a big deal to me.
I use two thin polarizers stacked. Rotate one to get variable neutral density.
That works by rotating two circular polarizers when their forward
looking surfaces are facing each other. One filter can be screwed on to
the lens but unless the second filter has a male thread on each side of
the optical surfaces the second filter cannot be attached to the first
one to achieve the desired effect. Attaching one filter to the other so
that both forward looking surfaces are parallel to each other generates,
with CPols I have, a colour shift ranging from a bright rosy pink to a
cyan / blue across the entire image.
Perhaps your idea might work if one was to combine one CPol and one
LPol, or two LPols, and screw them together so that their forward
looking surfaces were parallel to each other. Unfortunately I do not
have a LPol with me to experiment :-(
jh
jh
Jan
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