rmalarz Loc: Tempe, Arizona

Royce, a polarizer is an invaluable addition to your equipment. However, once placed on your expensive lens, it becomes part of the optical system. Therefore, don't buy cheap. Get a good quality one. My personal preference is B+W filters.

Another issue you will run into is that polarizers are directional. They produce their maximum effect in areas that are 90 degrees to the sun. Put one on a very wide angle lens and you'll see varying shades of darkening of the sky. So, it does have some limitations. Those limitations are outweighed by the benefits of color saturation and less detail obliterating reflections. I'd definitely recommend working with the filter you purchase so you know how it works best for you.
--Bob

dpullum Loc: Tampa Florida

Googling "scientific comparison of circular polarizing filters" and seeing the images answers the do and don't need question by example. Don't-need is when you are taking a beautiful shot of a reflection from the surface of the water.

While this topic will go on for 7 pages of opine at times it is best to resort to boring scientifically based information, you know, like global warming... numbers are important. For numbers on CPFs I refer you to a 2015 study: https://www.lenstip.com/139.1-article-Polarizing_filters_test_2015_Introduction.html

The study examines 23 brands. If science bores you jump to the conclusions: https://www.lenstip.com/139.25-article-Polarizing_filters_test_2015_Results_and_summary.html

As I recall in another UHH thread I did a plot of $ vs Points ... a conclusion of that plot disproves that "ya get what ya pay for" myth. Altho of course, within a family such as Hoya the myth holds true... sorta!

Me? Oh, I bought the 15th placed Zomei, for one-tenth the price of the second-ranked B+W Circular-Pol MRC. Zomei fits my budget and my usage... and .... I do a lot of post art like processing in keeping with my motto "No good photo shall go unmolested."

ecurb1105

Don't need one.

camerapapi Loc: Miami, Fl.

Let me warn you that a polarizer is not the best filter to use with wide angle lenses. Polarizers work best when at a 90 degree angle with the sun but in the case of a wide angle part of the sky will not be polarized making the sky look unreal. They do darken the sky but many users tend to use full polarization making the sky darker than it really is.
Polarizers act like a 2 stop neutral density filter which means that they will require 2 stops more of light than what the exposure indicates if not using the filter. NEVER use a polarizer with evaluative, multi pattern or matrix metering. The filter is dark and it will confuse the meter causing erroneous readings.
These filters are a godsend to suppress or eliminate reflections from non metallic surfaces so for many maritime scenes they will not only darken the blue water but could be of great help if reflections need to be removed. They are valuable also in the rain or during a cloudy day when used properly.
Steve Perry has an excellent video about these filters and a simple Google search should give you all the information you need.

frankraney Loc: Clovis, Ca.

Probably the most needed filter (other than uv to cover the lens). I would get the circular so you can adjust it. It cuts reflections in water and makes the sky bluer.

If i had to pick a favorite area on highway 1, it would have to be point arena area. The rock formations at the light are great.

Have a good trip...

jerryc41 Loc: Catskill Mts of NY

I would replace "need" with "should have." A CPL can make colors look better. They work best when used at a 90° angle to the sun. I've been using them since my film days.

https://www.lensrentals.com/blog/2017/09/my-not-nearly-complete-but-rather-entertaining-circular-polarizer-filter-article/
http://www.lenstip.com/139.25-article-Polarizing_filters_test_2015_Results_and_summary.html
http://www.techradar.com/how-to/photography-video-capture/cameras/best-circular-polarizer-filter-5-top-models-tested-and-rated-1320842
http://www.the-digital-picture.com/Reviews/Circular-Polarizer-Filters.aspx
http://www.lenstip.com/index.php?art=139

http://www.lenstip.com/115.1-article-Polarizing_filters_test.html
http://www.lenstip.com/115.4-article-Polarizing_filters_test_Results_and_summary.html
http://nikonrumors.com/2014/07/26/how-to-use-a-polarizing-filter.aspx/

PlymouthWoodworker Loc: Plymouth, MA

I agree with what the other folks have said. But you won't need a polarizer for the Tokina 11-16. This is a very wide angle lens and effects of a polarizer will vary across the field and result in weird lighting. As a general rule, polarizers don't work well on wide angle lenses.

olemikey Loc: 6 mile creek, Spacecoast Florida

Only filter I use, when needed.

olddutch Loc: Beloit, Wisconsin

Look out for Bicyles on the road. Came down from Oregon to SF and probably saw over 200 folks riding their bikes.

Bill Emmett Loc: Bow, New Hampshire

Every time I take outdoor photos I have my CPL handy. It does exactly what the previous posts have said, there is a big "but" in the type of CPL to have, and invest in. Look for a CPL with a brass mounting ring. Sometimes these filters gall to the threads on the lens and get stuck. If you find yourself having to remove the CPL quickly to get "that shot" and it is stuck, you may need a special filter wrench to remove it. Just don't damage those threads on the end of the lens.

B

tommystrat Loc: Bigfork, Montana

A CPL can vary the strength of the effect on the raw image, from highly polarized to just a bit of effect. So it can be very valuable in achieving the gradation of polarizing effects you are looking for. I generally shoot 3-4 images with a slightly different polarizing effect on each one to capture the ideal one I want. Also, can layer these exposures and get some really interesting skies.

Clapperboard

John F Maybe should have asked Kilroy. You're right, it's all about angles. That's why using a CPL filter on a wide angle lens WILL cause problems in the representation of the sky. Very lucky if you happen to not get problems when used with a wide angle lens. The problem may well be (in fact it's pretty well bound to be) there on the rest of the image but shows mostly on the sky.

jtwind

yup! You need one!

broncomaniac Loc: Lynchburg, VA

I use a hama CPL when water reflections are undesirable. Very good quality filter at a decent price.

CamB Loc: Juneau, Alaska

Besides all the water and sky comments, it's great for windows. When traveling, most of us will spend lots of time walking around in cities and towns. There are lots of great windows to shoot and to shoot through. I probably use my polarizer more on city streets than when out shooting 'nature'.
...Cam