Wrote Dan Lau:
>The markings on the edge are:
>
> V Hoya PL 49 Japan
>
>Where the "V" is a triangular arrow. "49" obviously refers
>to the size. And I don't know what the "PL" means.
>
>My guess is that it is a Polarizing filter, and if it is, since
>I have never used one before, I have the following questions:
It certainly is.
>
>1) Is it OK to leave a Polarizing filter mounted at all times
> on the lens, does it hurt anything? Or should I replace it
> with a 1A and mount it only when I need it?
It will hurt your exposure times! A pola filter steals about 1.5
stops of exposure. Also, you may not like the effect it gives you.
To find out how the filter works, just unscrew it and hold it up
in front of one eye while rotating it. Try it on a blue sky, in
different directions, on water, foliage etc.
>2) I know the Polarizing filter can be used to cut out glare,
> but how do I use the arrow for proper orientation?
You will see this through the finder as you rotate the outer ring.
The filter darkens a blue sky if the arrow points (as near as
possible) in the direction of the sun or 180° from it. Clouds are
not affected and stand out correspondingly.
>3) What are the other situations to use the Polarizing filter?
>4) Any advice on using the Polarizing filter with flash? How
> well does it cut out the reflections from shiny surfaces?
Seeing though water surfaces. Backlighted foliage (to cut down
on glare from the waxy upper surfaces of the leaves. Removing
mirages! (No kidding.) Remember that the reflected light has to
be polarized to be removed. A reflecting surface polarizes light
only if ithe light can penetrate somewhat below the surface. So fully
reflecting materials (mirrors, chromed auto parts) give reflexes
which cannot be removed. Try it on a car in sunshine! It will
darken reflexes from the paintwork but not from grille, etc.
A pola filter is most useful in the 35 -- 85 mm range. With a super
wide angle lens, trying to darken the sky may darken only part of
it, as the effect falls off rapidly at angles approaching the direction
of the sun, or 180° from it. With a tele, there may not be enough
sky to matter (but the filter may of course come in handy for
more earthboud reflexes).
Flash: only if you know exactly where the reflexes are and how
they are polarized! A flash exposure leaves no time for fiddling
with the filter! Ring flashes are of course often used with a composite
PL filter where the outer part polarizes the flash light and the inner
part is fixed at 90° from it, so you do not get ring-shaped highlights
on shiny subjects.
Vänliga hälsningar/Best regards
Lars Bergquist
Välkommen till/Welcome to ...
<http://www.bahnhof.se/~timberwolf/>
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