Circular Polarizing Filters
Normally
I don't carry lots of "extra" equipment beyond basic Camera/Lens, but
there is one case where I always bring something extra . . .
a Circular Polarizing Filter for Car Shows.
So Many Reflective Surfaces. Shiny body paint, windows, and chrome.
Here is where a Circ-Polar filter really shines. (Or doesn't "shine" . . . your choice.)
Same view of same car, with the Circ-Polar filter "twirled around" to eliminate the glare/reflection (mostly from the sky).
Look how much deeper and richer the reds and blacks are in the left image.
The right image has reflections from the sky and is "greying" or "blanding" the overall color contrast.
The right image just looks . . . "dull".
Now
look at the (left on the screen) fender. Yes, on the Left image,
you can see more reflections of cars/people from outside of the frame
on the left.
So, a circ-polar filter doesn't necessarily eliminate
all reflections, but it can change the DIRECTION of where light is
allowed to come from, and radically orient what you see.
By killing the glare from the sky, the colors on the left are richer and brighter. Contrast is improved.
Here's a (handheld) video example of three cars while twirling the circular filter around.
(When twirling with your finger, try and twirl the front element of the lens-pair in the direction of "screwing on",
so you don't unintentionally unscrew the filter, while trying to adjust.)
https://youtu.be/HoBGFLlULYk
I pretty much only use the CircPolar filter for Car Shows. But remember: "Every Blade of Grass in a Field . . . is a Reflective Surface".
There
are circumstances where you can get much deeper-richer greens, if you
use a Circ-Polar filter, even on non-obvious things like landscapes.
It's
also awesome for things like "Barber Shop" windows. Do you want
to see the Reflection in the window? Or the people INSIDE the
shop?
With a Circular Polarizing Filter . . . that choice is usually up to you, not circumstance.