lowkick Loc: Connecticut

Someone asked me if CPL filters had coatings. I never thought about it before, but I don't remember seeing them advertised as being coated and it strikes me that a coating might be counter productive to the purpose of a CPL. I don't think mine are coated. Do any of you know if CPL's are typically coated or not?

MtnMan Loc: ID

Absolutely.

And they are dust magnets.

I recently got a new Marumi that claims to be less of a dust magnet. I have yet to test it.

Carl D Loc: Albemarle, NC.

Yes, the better ones do. Tiffen, for instance has a multi-coating on their "HT" filters, and so do other manufacturers.

RWR Loc: La Mesa, CA

I believe an uncoated polarizer would be rather useless for most purposes.

rwilson1942 Loc: Houston, TX

Pretty sure that any quality lens or filter will have coatings.
Coatings are used to reduce reflections, boost light transmission, reduce flair, etc.

rgrenaderphoto Loc: Hollywood, CA

They all have anti reflective coatings.

hcmcdole

The more expensive it is usually means it has more coatings. Budget or premium? Hype or fact? Choices, choices....

wdross Loc: Castle Rock, Colorado

An uncoated lense might reduce the actual transmitted light by as much as 10 to 15 percent. A properly coated lense can transmit light as much as 98+ percent. Properly coated lenses come at a premium cost though.

gwong1 Loc: Tampa, FL

lowkick, I am attaching a Hoya filter catalog, which explains how they make and coat their filters. Gary

Attached file:
(Download)

dpullum Loc: Tampa Florida

Coatings are norm; how many coats makes a difference. But can you really detect it??? perhaps! perhaps not! Optical ground glass, vs, float glass... now-a-daz little difference. I have given references on coatings and quarter wave materials before... too lazy to look it up again.

What counts regarding CPL is the 1/4 wave disrupted-retarder (no not the one in space adventure programs) first read the physics of polarizers. But, remember there are some things we a photographers just should not know.... innocence is bliss. IMO, Composition trumps quality.

Physics is a subject which does not allow one to sleep peacefully pondering equations disrupts the tranquility. We photographers find using Automatic (focus, exposure etc) everything on our cameras and buying only the most expensive of materials ... filters... etc.

So if you dare start here:
https://en.wikipedia.org/wiki/Polarizer

Test results mess up the fun in UHH of opinion (right or often wrong) .... but if you would like you can start here:
http://www.lenstip.com/index.php?art=139

Or skip the detail stuff and go to Conclusions:
http://www.lenstip.com/139.25-article-Polarizing_filters_test_2015_Results_and_summary.html

Remember eating of the Macintosh Apple (or Microsoft PC) of knowledge is forbidden... ask Eve

Reinaldokool Loc: San Rafael, CA

Yes.

rmalarz Loc: Tempe, Arizona

I use B+W filters and they are coated.
--Bob

imagemeister Loc: mid east Florida

Today, the better ones are coated and multi-coated . For most of the film era, none were coated and we got along fine .....

amfoto1 Loc: San Jose, Calif. USA

There are both coated and uncoated CPLs. (Hoya makes five or six different "grades" of CPL. Even B+W makes several types: uncoated, single coated, multi-coated, and advanced multi-coated "Nano").

The better ones are multi-coated and because CPL use multiple layers of glass those coatings are very likely more important on them than on other types of filters.

Mtn Man is correct... they can be "dust magnets" and difficult to clean. The latest and greatest (such as B+W "Nano" coated or similar from Hoya and others) have up to 16 coatings, including some that make them more dust resistant and easier to clean.

You'll also find more expensive "slim" CPL, as well as those with "standard" frames. The slim ones might be needed for some ultrawide lenses. But they are not only more expensive, they also can be more difficult to install, use and remove, due to the thinner frame sections that are harder to grip and more prone to flexing. Some slims also fore-go front threads, which means that most standard lens caps can't be used with them. All in all, if possible stick with standards (B+W standard frames are already pretty slim and I've never had any vignetting issues with them, even on 10mm and 12mm crop and 16mm, 17mm full frame ultrawide zooms. But it really depends upon the specific lens.)

The very latest-and-greatest CPL today are "HT" or "High Transmissive", offered by several different manufacturers. Those are lighter in appearance and stop less light than earlier designs. Non-HT CPL can reduce up to two stops the light reaching the camera sensor. Supposedly the HT only reduce it about 1-1/3 stops at most. Can't say yet if they are as effective at polarizing or not... I just got a B+W HT CPL to try out, but haven't used it very much yet.

photoman022 Loc: Manchester CT USA

If you want to see if it has a coating, apply lens cleaning solution directly to the CPL and watch the beautiful rainbow colors appear! DON'T do this in real life!!!! or you will ruin the CPL.

When you clean the CPL, moisten the microfiber cloth with the lens cleaner, start in the center and work out toward the rim with a gentle circular motion. I realize this part of my response is off topic, but after making the first statement I figured that I better follow it up with the proper way of cleaning a CPL (or any other type of filter).