At 03:51 PM 10/8/98 +1000, you wrote:
>"R.S. Adams" <aeolian@xxxxxxxxxxxxxx> moved upon the face of the 'Net and
spake thusly:
>
>> Okay, gang. . . here's the dumb question of the month. What is the
>> practical difference between a circular and linear polarizer? Is there
>> a difference in the effect produced? The amount of light attenuated?
>> Both? Neither? What's the story. I've have not used a PL in a long
>> time (more than I care to admit) -- I need to buy a couple and want to
>> get the straight scoop.
>
>OK.
>
>Polarizing screens (aka linear polarizers) block all waves except
>those in a certain plane.
>
>Some TTL metering systems use beam-splitters and/or half-silvered
>mirrors to redirect some of the incoming light to the meter.
>
>If the light is plane-polarized, it disrupts the function of the beam
>splitter.
>
>Using a linear polarizer on such cameras will send your metering to
>shit.
>
>A "Circular Polarizer" consists of an ordinary polarizing screen,
>followed by a "quarter wave plate" which "depolarizes" the light.
>The effectively unpolarized light will then behave OK in the metering
>system.
>
>So if you use a PL (linear) filter, the light is polarized all the way to
film,
>but with a PC (circular) filter the polarized light gets "scrambled"
>again after passing the screen.
>
>HTH,
> Chris.
>
Nice explanation... OK... I saw somewhere, a document which specified
which type of filter to use for each of the OM cameras. Any idea which
filter is required by each camera?
The reason I ask, is because I have an OM-1n, and am considering getting
either an OM-2n or OM-2s. I need to get filters for my existing lenses,
but I would like to just get one filter for each. I would expect that the
1n can take the linear, but I was thinking that the 2s needed circular.
What about the 2n?
Regards,
Dan M.
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