Do any of you use special filters and have general advice and/or techniques
which you could pass on to us?  I use a polarized filter a lot with excellent
results.  It gives cloud enhancement (Sky darkening) and reduction of glare
on water.  If you shoot things like grassy fields, you can intensify the color
with polarizing filters also.  The glare is not obvious, but if you look
through the filter, you see the color intensity rise and fall as the filter
is rotated.

16 responses total.

I like polarizing filters too, but I've heard you have to compensate for the
fact that the mirror in your SLR polarizes the light entering your meter
anyway...if you polarize it twice you get a less than perfect exposure.

I also like UV filters.  There is little noticeable effect except to cut
through the "haze" of early morning or early dusk.

I've played around with special effects filters/gadgets, but they're more
trouble than they're worth, unless you are doing a totally set-up shot and
need such an effect.

When the exposure is made on an slr, the mirror is out of position and should
not alter the exposure.  It may affect what you view through the finder,
however.  I know they sell "circular polarizers" which I have bought.  These
cost about double a standard polarizer and the only explanation I could get
was that the focusing systems would not work properly without the "circular
Polarizer."  (I don't really know).

If you are shooting desert colors or fall colors, warming filters do a great
job.  They probably give a "fake" color intensity, but if you shoot two
pictures, one with the warming filter and one without, most people will
clearly favor the one with the warming filter.

I have never used the "star" filters, the "soft" filters, etc.

Of course the _exposure_ is not affected by the mirror when the picture is
taken, but when you frame your shot with a polarizing filter in place the
mirror adds additional polarization (re-directs all incoming light to one
plane) and that is what _your exposure meter_ reads.  When the shot is taken,
your exposure is less than perfect...as I understand the logic.

What I've always done to compensate for that is to set the ASA/DIN of the
camera to fool it into thinking the film is either one stop faster, or one
stop slower, than it actually is (faster for slides, slight underexposure
yields deeper image...slower for prints, slight overexposure yields deeper
image - but lots more latitude with prints anyway).

        [did that make sense?  I re-read it, and I'm sure it's what I
         meant, but it looks a little confusing.]

Yes, at best you could consider the polarizing filter a weak neutral density
filter and what you said makes sense.  

The way I have rationalized the filter, is that it only acts on glare,
therefore, I make no correction.  My exposures are vivid and saturated.  The
only way I get a funny effect is when I use a super wide lens and have a lot
of sky.  Then the polarizer varies from light blue to dark blue sky because
the maximum deep blue is 90 degrees to the sun and the least effect is 90 and
180 degrees to the sun.  

Hello everyone ... I went through all responses.
You people are discussing some real good things.
I have a Minolta 500 si with a simple UV filter and the UV filter
gives excellent clarity to my pictures.
I am planning to buy some colour filters. Can someone help me by
suggesting which brand i should go for and how much it will cost me ?

Unless I'm mistaken, most are actually made by just one or two
companies...unless you go for some very high end german-type stuff.

Depends on how serious you are.  I had some good results using a system by
Kokun (?), which had an adapter that fit to my lens and then I could
interchange specialty filters quickly.  They had a full range of star,
diffusion, multi-image, etc, filters, as well as the usual sky-light, and
color filters.

Now, I usually stick with the UV.

The Cokin filters rickyb referrs to are probably the ones most often seen in
credits on the photo contest winners.  I have never used them, but they appear
to be the choice of serious amateurs and pros.  The screw-on ring type glass
filters are made by Hoya and others are pretty good.  A lot of great buys can
be had at the photo-rama shows (Used equipment, mostly) that are held 2-3
times per year at local motels.  

Hmmm... I never thought the Cokun stuff was good enough for pros :>

Main advantage is quick interchangeability so you can do a lot of different
things with the same shot/lighting/etc in a short time.

I forgot to mention, besides a UV, I like the use of a polarizing filter a
lot.  I seem to get much richer definition with the reduced glare.

someone told me once, however, to compensate when using a polarizer.  Seems
the mirror in an SLR _already_ polarizes the light being read my the meter,
and it adjusts internally to a non-polarized reading so when the mirror moves
out of the way you get a proper exposure.  By polarizing the light being read
by the meter _twice_ you should compensate.  I've tried but find that in all
practicality i can usually still trust my SLR meter to give me the correct
exposure.  [when in doubt, bracket]

I don't know the technical reason, but if you have a camera with through the
lens autofocusing, you are supposed to have a "circular" polarazed filter
rather than a standard polarized filter.  The circular one, of course is MUCH
more expensive.  

If you have multiple lenses, it is good to try for the same filter size on
as many as possible.  Another consideration is whether or not the filter turns
as the lens focuses.  With polarizing lenses, a lens which turns as it 
focuses would require adjusting the polarizer after focusing each shot.

I've usually used an 80A filter with Kodachrome 64 (outdoor) color
film with 3200K tungsten lamps, with fine color rendition. I've now
read that I could use ordinary 75 or 100W bulbs with a combination
of an 80A and 82A filter. That would be "cool"(er). Has anyone tried
this and, if so, how was color rendition?

Re #9: I'm not sure why it'd affect autofocusing specifically, either.  
There's also the issue of whether the lens is "internal focusing" 
or "external focusing".  On an "internal focusing" lens (most still 
camera lenses are in this category) the filter ring end of the lens 
(and hence the filter) does not rotate as the focus is adjusted.  On 
an "external focusing" lens (many inexpensive video camera lenses) the 
filter ring *does* rotate.  Obviously on an external focusing lens you 
need a circularly polarized filter, since there's no way you can 
maintain the proper alignment of a linearly polarized one.

Currently the only filters I own are UV or "Skylight" filters.  Among 
other things, they're a relatively cheap way to protect the business 
end of my lenses...

polarizing filter...i like to push it a stop past what my
thru the lens meter tells me is a correct exp. for slide
film, which is less forgiving, BE CAREFUL...

I keep the polarizer on 99% of the time. The only other one I use
with any frequency is the x4 ND (during the summer) to allow me to 
get a slightly narrower DOF.

I have a X6 cross screen filter, but I haven't had time to play 
around with it yet.

I also have a cooling (82A) and warming filter (85), but with digital
they aren't needed, because you can fakeout the white balance using
different color grey cards.

Would you enlarge on the last point, please? I use an 82A(+ another) for
stand photography with daylight slide film and photolamps. Why isn't that
also necessary for digital photography? I know you can redo color balance
in digital, but I didn't know there was a utility for the equivalent of
color balance filtering with the numbered glass filters. Also, how are
color grey cards used (and where do you get them)?

With some digital cameras, you can change the white balance on your 
camera. Most digicams have pre-sets like - sunny, cloundy, fluoresent, 
tungsten, flash and auto.  The more advanced cameras also have the 
ability to set the white balance manually.

In film photography I think gray cards are used to help set the shutter 
speed and aperture. With a digital camera, you can see what your image
will look like so a graycard isn't needed. But because of their neutral 
gray color you can use it to set the white balance.  By changing the 
color of the cards to a slightly bluish hue, the overall result will be
a warmer photo.

they sell these cards commercially, but I use matte 4x6 paint sample 
cards from Loews. The nice thing about the cards sold commercially is 
that they are labeled; where with the sample paint cards, its more of
an educated guess and experience on what works.

On this website are some sample pictures of the effects of using the
different color cards.    http://www.warmcards.com/digital_camera.html

Ahhh...you have to have a camera with white balance (WB) control. Mine
doesn't. I'm also an "old time" photographer, and work in terms of color
temperature - or Wratten filter series. What I would like for my camera is
the computer utility for invoking an equivalent Wratten filter for digital
images.

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