Polarizing filter vs. Non-filter

[Stinky]

Just thought this was a good example of the effect of a polarizing filter. I am not expert but they do make a difference. No PP to either photo.


Filter


Non-filter

[Manfred M]

Yes - rather than having a UV or clear filter on my lenses, I have a polarizer on them pretty well 100% of the ime when I shoot outdoors. You have clearly demonstrated why I do.

[Stagecoach]

Just thought this was a good example of the effect of a polarizing filter. I am not expert but they do make a difference. No PP to either photo.

A good example Steve

[Sanderson]

Very good example, one of the best filters to have.

[William W]

Be careful when you get to around FL = 30mm and wider on 135 Format (aka 'Full Frame'); or about FL = 19mm and wider for APS-C Format, especially if the scene has expanses of Blue Sky or Water that stretch across the image: as you might capture a segmented polarizing effect that you don't want and which is difficult to remove.

WW

[chauncey]

I'm gonna jump in and show my lack of education regarding polarizing filters...I was under the impression that the only thing they accomplish is to cut down on glare and/or allow a slower SS when wanted???

Assuming the two images had identical camera settings...the image without the polarizer is much flatter looking, the other less so, but not by much. Running them both thru LR...indistinguishable.

If you need a slow SS...use the filter. Right or wrong???

[Manfred M]

I'm gonna jump in and show my lack of education regarding polarizing filters...I was under the impression that the only thing they accomplish is to cut down on glare and/or allow a slower SS when wanted???

Assuming the two images had identical camera settings...the image without the polarizer is much flatter looking, the other less so, but not by much. Running them both thru LR...indistinguishable.

If you need a slow SS...use the filter. Right or wrong???

Polarizers primarily cut down glare and reflections from non-metallic surfaces. That is one of their primary uses and what is clearly shown in these two images. A consequence of this is that they do not transmit all of the light that hits them, hence that ND effect that you describe.

A second impact is that they do darken the sky (same principal) with maximum impact 90 degrees from the sun. This causes the banding Bill was referring to in his post.

[dje]

Be careful when you get to around FL = 30mm and wider on 135 Format (aka 'Full Frame'); or about FL = 19mm and wider for APS-C Format, especially if the scene has expanses of Blue Sky or Water that stretch across the image: as you might capture a segmented polarizing effect that you don't want and which is difficult to remove.

WW

for example, shot in Turkey recently - 17mm on 1.6x crop camera

As Bill says, it's difficult to correct this in pp.

[William W]

Assuming the two images had identical camera settings...the image without the polarizer is much flatter looking, the other less so, but not by much. Running them both thru LR...indistinguishable.

I think that it is quite reasonable to state that there is more depth and also more tonal range in the REFLECTIONS in the water of the image where the CPL Filter was used.

When using a CPL correctly these two features in the final image are more apparent in the high res image than a compressed low res file displayed the internet.

Maybe the same effect could be got using Lightroom (and from the original file, not an internet download ex a web forum): I don’t know and I wouldn’t necessarily try, because it is usually much easier just easier to use a CPL Filter.

***

If you need a slow SS...use the [CPL] filter. Right or wrong???

It is not best practice to use a CPL for the role of a Neutral Density Filter. An ND is better to use if one simply wants to use a longer Shutter Speed, (or a larger Aperture) at any given ISO.

There are a few reasons for choosing an ND Filter over a CPL Filter for these purposes, the mains ones are: designated and known attenuation and no likelihood of a segmented polarizing effect, which I mentioned in Post #5.

But a CPL Filter could be used in an emergency to perform the in the role of an ND Filter. One can expect to get a range of attenuation possible, between 0 (Zero) and approximately up to 1½ Stops in some circumstances.

WW

[William W]

. . .for example, shot in Turkey recently - 17mm on 1.6x crop camera

Thanks for that, Dave.
I was running diagnostics and updates and defragging on my main computer and was waiting until that had all finished before found and uploaded an example that I keep on it.
You saved me the effort.
Thanks again.
Cheers.

[Shadowman]

I also use my CPL to get a different look in metal, glass structures in direct sunlight. The change is very subtle but looks nice as it adds additional contrast.

[dje]

Thanks for that, Dave.
I was running diagnostics and updates and defragging on my main computer and was waiting until that had all finished before found and uploaded an example that I keep on it.
You saved me the effort.
Thanks again.
Cheers.

No problems Bill, I have plenty of examples of photography gone wrong

Dave

[pnodrog]

No problems Bill, I have plenty of examples of photography gone wrong

Dave

Yep - I also have many examples of technology just not living up to my photographic creativity....

[William W]

haha.
We all do . . .

[Glenn NK]

CPLs are great - unfortunately physics lessens their usefulness - the amount of polarization is a maximum when the angle between the sun's rays and the line of sight is 90 degrees, and it falls off as this angle diminishes. The angle isn't just the horizontal or vertical angle, it's the true angle between the optical axis and the direction of the sun.

In the example posted by Dave Ellis - draw a line from the centre of the image (assuming it hasn't been cropped), that is 90 degrees to the chimney shadow on the roof - it will point to where the sun was. Obviously it's the darkest spot on the sky.

CPLs worked great when my widest lens was 55 mm FL, but for a 24 mm lens, there are obvious problems. As a consequence, I don't use them as much as I used to.

Glenn

[rpcrowe]

Here's why I use a polarizer...

1. To darken the sky and maximize the clouds and to prevent a washed out sky...
2. To increase the vibrancy of colors in just about any non-metallic surface but, especially in foliage and rock formations...
3. To cut haze a bit by reducing the reflections off water and other particulates in the air...
4. To cut the exposure and either allow a slower shutter speed or allow shooting at a wider aperture...
6. To cut reflections in water and glass surfaces allowing you to see through the glass and below the water surface and to remove disturbing reflections...

I am sure that there are some other reasons I use the CPL...

I don't usually have problems with banding caused by polarizing filters on UWA lenses in landscape shots since I don't like using UWA lenses for landscapes...

However, I will always remove my CPL before I shoot an extended pano to ensure that the various images will match...

[Manfred M]

CPLs are great - unfortunately physics lessens their usefulness - the amount of polarization is a maximum when the angle between the sun's rays and the line of sight is 90 degrees, and it falls off as this angle diminishes. The angle isn't just the horizontal or vertical angle, it's the true angle between the optical axis and the direction of the sun.

In the example posted by Dave Ellis - draw a line from the centre of the image (assuming it hasn't been cropped), that is 90 degrees to the chimney shadow on the roof - it will point to where the sun was. Obviously it's the darkest spot on the sky.

CPLs worked great when my widest lens was 55 mm FL, but for a 24 mm lens, there are obvious problems. As a consequence, I don't use them as much as I used to.

Glenn

Glenn - while this is true when the sky is a significant component of your shot, it is not an issue when dealing with reflections from non-metallic objects, as localized scattering occurs there and the polarizer helps, regardless of the position of the sun or even the light source.

[Glenn NK]

Glenn - while this is true when the sky is a significant component of your shot, it is not an issue when dealing with reflections from non-metallic objects, as localized scattering occurs there and the polarizer helps, regardless of the position of the sun or even the light source.

Manfred:

True enough; and although the amount of polarization on everything will vary with the angle, it's not nearly so apparent as it is in the sky.

I think the image posted by Dave Ellis is a classic example of what can happen to a sky, and it's not noticeable anywhere else.

The images posted by Steve (the OP) also illustrate how effective polarization is for water.

Glenn