roger55 Loc: Tampa Bay Florida

Since I added a polorizer lense on my Canon EOS R there has been a purple out line on trees which I don’t always see thru the viewfinder. I remove most of it when I process the image thru photos.
Short of removing the filter what do you suggest ?

Mark Sturtevant Loc: Grand Blanc, MI

I might be off, but it does seem like chromatic aberration, introduced or enhanced by the polarizing filter. This especially happens with strongly contrasting boundaries like foliage against the sky.
There are procedures to remove this artifact during post-processing. Look for information on that with whatever software you use.

Brian S. Loc: Oak Park, MI

What was the object of adding the "Filter" in the first place? Do you shoot everything using it rather than a UV Filter?

Thanks

Brian

Rick from NY Loc: Sarasota FL

Sure sounds like chromatic aberration. Does it happen without the filter? If it is only when filter is mounted, perhaps your polo is poor quality? Shouldn’t happen on a regular basis with a good filter

CHG_CANON Loc: the Windy City

You should post an unedited JPEG example and store the image file for inspection by the UHH community. These guesses so far may have nothing to do with the filter being used. We should all analyze the same example image(s) and seek to identify exactly the issue that could be the lens used, the lack of a corrective profile, the aperture employed, as well as other sorts of issues / solutions unrelated to the filter assumption.

amfoto1 Loc: San Jose, Calif. USA

Why don't you consider removing the filter?

Circular Polarizing filters are NOT intended for continuous use. They serve specific purposes. But there are many times when you shouldn't have one on your lens, such as...

- In low light conditions because a C-Pol absorbs 1 to 2 or more stops of light, forcing you to use higher ISOs and/or slower shutter speeds or larger apertures.
- Shooting a rainbow. A polarizer will cause it to disappear (rainbows ARE unpolarized light, light that's been "scattered" by water droplets in the atmosphere).
- When the reflections ARE the image.
- When directly shooting a bright light, such as a sunset or sunrise. The added multiple layers of glass of the filter increase chance of flare AND the filter serves no purpose because the polarizing effect is zero when pointed toward the light source (or 180 degrees from it). The polarizing effect is strongest at 90 degrees from the light source, but diminishes and eventually vanishes as you approach 0 or 180 degrees from the light source.

For example, I deliberately shot the below image WITHOUT a polarizer because I didn't want to lose the reflections of the sunlight off the water, wet sand and wet rocks... AND because the filter essentially served no purpose but would likely have increased flare...



However for this next image the sun was overhead and slightly behind me, so I used a C-Pol carefully to deepen the blue of the sky and the green of the water. I didn't use the full strength of the filter though, because I wanted to keep some of the reflections on the water...



On the other hand, in the image below the setting sun was almost directly behind me, a C-Pol served no purpose so I didn't use one...



Even though it was in the shade, for the close-up shot below I did use a C-Pol because it reduced the reflections off the foliage, deepening the colors...



But for this spider in its web I made a point of NOT using one because I was concerned it would reduce the glistening reflections defining the web...



Here's a somewhat abstract example where a C-Pol would have ruined the shot by eliminating the reflections (it's rainwater on an oily patch in a parking lot)...



"Purple fringing" is chromatic aberration (CA). It may or may not be due to the filter you're using. I would certainly do some test shots without the filter to see if it's better. But it is possible to get CA in high contrast situations with just a lens alone. Or it could be that there's some from the lens, and the filter is exaggerating it. Some lenses are just better than others resisting CA. And sometimes CA can be easily corrected in post processing. Other times it takes a lot of work to correct in pos... Or it simply ruins the image.

All that said...

A Circular Polarizer is one of the most useful filters for digital photography. It's able to do things that simply cannot be done very well or at all in post-processing. Most other types of filters (color corrections, warming, graduated ND, color conversion, intensifying) are no longer useful or needed with digital photography. We can make most filter effects either in camera or in post-processing. For most photographers today a C-Pol will see more use than any other type of filter. But even so, depending upon what they typically shoot, a photographer may only use a C-Pol 25%, 10% or even 5% of the time.

You didn't specify what brand/model of filter you're using. There are good quality, for sure... But also a lot of cheap junk, uncoated filters that can degrade images badly. Some brands make good, bad and some in between. Hoya, for example, makes five or six different C-Pol that range from cheap to expensive. I think high quality Hoya are their HD3? NXT? Heliopan, Formatt Hitech, Lee and other brands also offer top quality.

Since any filter will directly effect every image shot through it, and so few filters are needed when shooting digital, in my opinion it's worth spending extra for top quality. For years I've been mostly using B+W multi-coated (either F-Pro or X-Pro), but they've gone way up in price recently. So I've been experimenting with some K&F Concepts brand that are much less expensive (since B+W prices have increase dramatically) but claim to use the same German Schott glass and similar nano multi-coatings. For comparison, the current B+W "Master" series 72mm C-Pol costs $176 (the previous top-of-the-line B+W X-Pro sold for around $110 in that size). The K&F top-of-the-line "Nano" (XC15?) series in 72mm costs $34 (bought direct from the Hong Kong "Kent Faith" website... one to two weeks shipping).

One of the images linked below (so you can enlarge, if you wish), was shot with the much cheaper, but still supposedly really good K&F filter. The other image was shot with a B+W F-Pro multi-coated C-Pol. Both shots are of the same tree at different times of year using the same 24MP (APS-C) camera... but two different lenses (22mm and 12mm).

Finally, I agree with Paul (Chg_Canon)... We could do a better job helping you if you'd upload an example for us to see.

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spaceylb Loc: Long Beach, N.Y.

Wow