Round Filters for Landscapes

[ShipleyNW]

I don't use filters much. They're kind of a pain in the butt. I really like using a polarizer when I'm out in harsh light. It cuts through the haze a bit and puts some contrast in the sky. But I hate fiddling with them. If I have a good day with a polarizer early in the season, there's a good chance I'll just leave it on all summer instead of a clear filter (which I use for protection.) I'll take the hit in the loss of neutral density light, but that becomes a problem mornings and evenings.

I've tried square filters, but that triples the hassle.

Now they have magnetic filters and the interwebs seem to love them. I'm thinking about getting a set. Has anybody used them? Any thoughts?

What size should I get? With my screw-on polarizers, I just go with the size of my lens' filter threads (mostly 77mm) but that doesn't give me full coverage at 24mm. The reviews talk about vignetting, but I don't think that's what I'm seeing. I'm not seeing the rim of the filter darkening the corners. What I am seeing is that when I dial in the polarization effect, the effect itself isn't wide enough to get all the way to the corners of a 24mm field of view. The polarization effect gets bunched up in the middle of the frame and leaves the corners hazy and pale. Is that considered vignetting? The polarization effect only seems to covert about a 30-35mm FOV.

I've been wondering if going one size up would fix that problem. I'm not crazy about having the widest part of my lens out there on the front. I'd much rather have a filter that's the size of the lens, but if it will fix those wide corners, I might be up for an 82mm set rather than 77mm.

So, round filters in general and magnetic filters in particular; any thoughts about how to use them best for wide landscapes?

 

[paddler4]

I doubt that what you are seeing is the CPL only covering part of the lens, and I doubt that buying a bigger filter would help. Given that the filters are built from circles cut from larger sheets of class, the polarization should be identical across the width of the filter. I suspect that what you are seeing is the effect of angle of view. The amount impact a polarizer has depends on the angle at which the light hits the filter, and with a very wide-angle lens, that angle near the edges is very different from the angle near the center.

I'm no expert about this, but that would be my bet.

 

[Dicky109]

What I am seeing is that when I dial in the polarization effect, the effect itself isn't wide enough to get all the way to the corners of a 24mm field of view. The polarization effect gets bunched up in the middle of the frame and leaves the corners hazy and pale. Is that considered vignetting? The polarization effect only seems to covert about a 30-35mm FOV.

I've been wondering if going one size up would fix that problem. I'm not crazy about having the widest part of my lens out there on the front. I'd much rather have a filter that's the size of the lens, but if it will fix those wide corners, I might be up for an 82mm set rather than 77mm.

Many people do not use CPL filters on wide angle lenses because of exactly what you are finding. Due to the wide field of view, one part of the image may be at a different angle from the sun and It doesn't matter the size of the filter. Keep in mind that the maximum effect of a CPL is at 90° from the light source, so as you get farther from the 90°, the effect is less causing parts of the image to look different from other parts.

 

[ShipleyNW]

I ordered a set today. Went with the native lens size of 77mm.

 

[paddler4]

Many people do not use CPL filters on wide angle lenses because of exactly what you are finding. Due to the wide field of view, one part of the image may be at a different angle from the sun and It doesn't matter the size of the filter.

Exactly. given two CPLs manufactured to the same specs, you will get the same issue regardless of how big the filter is. The only difference would be vignetting. This is why many people simply don't use CPLs on wide angle lenses.

There are lots of postings on the web showing precisely this problem. E.g., https://www.digitalphotomentor.com/...lar-polarizing-filters-wide-angle-lenses-sun/

 

[ShipleyNW]

Exactly. given two CPLs manufactured to the same specs, you will get the same issue regardless of how big the filter is. The only difference would be vignetting. This is why many people simply don't use CPLs on wide angle lenses.

There are lots of postings on the web showing precisely this problem. E.g., https://www.digitalphotomentor.com/...lar-polarizing-filters-wide-angle-lenses-sun/

I've seen the effect for a long time but, in my fairly-significant research on filters, I'd never run across a description of the problem with wide-angle lenses. (Thanks for the article.) Does this have a name, separate from vignetting? Most of the reviews and tutorials on polarizing filters focus mainly on removing reflections, and that can be handy at times, but I mainly use a polarizer for its effect on skies.

 

[paddler4]

It's not vignetting. That's a darkening that happens because there is a physical obstacle in the path of light at the edges, either because of lens design or because of the rim of a filter. I've never seen a name for the phenomenon you are discussing, but it's well-known. It's just physics, so there is no way around it with a standard CPL. Perhaps one could design a filter with progressively weaker polarization toward the center, but I've never seen such a beast, and maybe it isn't even possible. The only solutions I've ever seen for this are to leave the filter off or frame with a narrower angle of view.

 

[Lester Wareham]

Yes this is unavoidable with polorizers on wide angle, it is not a fault or artifact.
But is just the real effect of the variation or light polarisation over the angle of view.
Sometimes it looks good, sometimes not, just depends.

 

[ShipleyNW]

I've been seeing this for a while now. Made me wonder if it was something I was doing that I could avoid, something I could fix. Good to know it wasn't just me, I guess. I do look for it now and while I don't like it and didn't know what caused it, I could make decisions on how to mitigate its effects. Once you guys pointed out that it's a thing, I went on the internet looking for info. I got tips to zoom in or put the effect in one corner and try to hide the other corner. I'd kinda figured those things out myself out in the field.

Is this a circular polarizer thing or does it happen with linear polarizers too? Maybe I just didn't recognize it then, but I don't remember seeing this back in the film days when I shot with a 24mm lens and a polarizer.

 

[paddler4]

I think it should happen with any kind of polarizer. Polarization depends on the angle of the light.

My recollection from my distant past is that linear polarizers are more effective. If I remember right, the problem is that they interfere with modern AF systems, but I may be remembering incorrectly.

 

[Lester Wareham]

I've been seeing this for a while now. Made me wonder if it was something I was doing that I could avoid, something I could fix. Good to know it wasn't just me, I guess. I do look for it now and while I don't like it and didn't know what caused it, I could make decisions on how to mitigate its effects. Once you guys pointed out that it's a thing, I went on the internet looking for info. I got tips to zoom in or put the effect in one corner and try to hide the other corner. I'd kinda figured those things out myself out in the field.

Is this a circular polarizer thing or does it happen with linear polarizers too? Maybe I just didn't recognize it then, but I don't remember seeing this back in the film days when I shot with a 24mm lens and a polarizer.

Any polariser I should think, just physics; typically circular polarisers are used because linear mess with the metering system or something. At least with DSLRs, I presume the same applies to mirrorless.

 

[Archibald]

Circular polarizers and regular polarizers work the same way, but circular polarizers have a layer that UNpolarizes the light after it has done its polarizing job. That way the light continuing into the camera is not polarized and won't be a disadvantage to systems in the camera.

Polarizers reduce light and are fussy things. I think many these days shun their use and just darken skies in post-processing. I have some and hardly ever use them. But for special situations such as shooting through glass or a water surface at an angle, I would use them.

 

[ShipleyNW]

Polarizers reduce light and are fussy things. I think many these days shun their use and just darken skies in post-processing. I have some and hardly ever use them. But for special situations such as shooting through glass or a water surface at an angle, I would use them.

I don't find polarizers fussy at all. I cut my teeth shooting film in southern California with its never-ending pale-blue skies. A polarizer was an easy way to tame those some. I think I mentioned up above that I've gone entire summers where I just left a polarizer mounted up all season.

Polarizers work on a very specific type of light. Dialing in the effect can be fussy, I guess. But if you miss, the worst thing that can happen is nothing. And it's pretty easy to dial in nothing on shots where you don't need the polarizer's help. They do cost you light, but if you need a polarizer to cut haze, you probably have some light to spare.

And if you don't have the light to spare: magnet filters. Mine arrived Sunday. 77mm, per the knowledge gleaned here, many thanks. I'm gonna take them out tomorrow. I'll probably just leave the CPL mounted up. Forecast calls for light cloud cover. Hoping for some good skies.

 

[Archibald]

... They're kind of a pain in the butt. ....

... I hate fiddling with them.

I've tried square filters, but that triples the hassle.

But...

I don't find polarizers fussy at all.

LOL.

 

[ShipleyNW]

But...

LOL.

: Magnet Filters

 

[paddler4]

Polarizers are the one filter I still use now that I am 100% digital that can't always be replicated in post. If one is just darkening the sky, they aren't essential. It's now easy enough to select the sky and play with it. However, the other effects of polarization are very hard and sometimes impossible to replicate in post. For example, it can change foliage, and of course, it can reduce reflections.

What I find fussy is two things. First, some of my lenses have hoods that make it hard to rotate the filter. Second, with circular polarizers, the impact of rotation can be fairly subtle, requiring some trial and error. With my old linear polarizers, it was immediately apparent what position maximized the effect.

 

[Archibald]

... However, the other effects of polarization are very hard and sometimes impossible to replicate in post. For example, it can change foliage, and of course, it can reduce reflections.

Agreed. As with all filters, use them when they are needed, and don't use them when they are not needed.

 

[3Rotor]

I am certainly in the camp of using CPL filters. In fact, CPL and ND filters are my most used. I do not remember the last time I went sans CPL in my automotive work. I do use Haida's 100mm filter system. A single Haida CPL and step down rings to fit various sized lenses. A square system is convenient for me since I also rely on ND filters. Sure, it is a bit more gear to carry and a bit more to the workflow but the results are worth it for my needs.

 

[ShipleyNW]

The Evergreen State capitol in the midday sun with my new Kase Revolution Magnetic CPL.

Took my new magnetic filters out for the first time. I only used the CPL today but that's really why I bought the set. It's friggin nice. It's really thin because it doesn't have a frame. Screw-on CPLs need a frame to let the glass spin. That takes up a some millimeters at the edge of the image frame. With the magnet system, the CPL is one piece and no threads involved. The filter slides around in the magnetic mount. No binding, ever. That was a gripe I had with screw filters. I could only turn them one way; to my left from behind. If I passed through the best effect I'd have to go all the way around again. If I tried backing it up, there was a good chance of unscrewing the filter.

Verdict on the CPL hardware compared to screw-on filters: Much easier to use, less chance of vignette, light modification works the same, cost much more and require expensive accessories.

I'd never rationalized that 90° angle thing with a CPL. I'm sure I saw it, but it never clicked that 90° is a pretty key number. I paid attention to that today. The result of straying from 90° is that the filter stops working. If you have the sun at your back a polarizer won't help. On the other hand, if you have the sun at your back, you don't need a polarizer as much. So, I still believe the worst thing that can happen with a CPL is nothing.

But it turns out I shoot near 90° a lot of the time. I do want my shadows. That's the light I look for. And a polarized image in bright sun just looks better to me. So much so that I think I'll just leave the CPL mounted up until it gets in the way. And then I can just pop it off -- HA! The kit I got only had hardware for one lens. I took two lenses out today and put a screw-on polarizer on one of them. I'm gonna leave the CPL on that lens too.

I did order that magnet hardware for the second lens. It was $30 and they'll get it to me in 2-3 weeks, so they say. I mentioned earlier that I considered an 82mm set, but the step-up hardware for my 77mm lenses would have added $100 to the kit with no help on wide-angle performance.

I bought the Kase set because I found a good deal that made it the cheapest option among its peers. I did some research and I'm sure the others I looked at would have been fine too for the same reasons I liked the Kase.

 

[Lester Wareham]

Circular polarizers and regular polarizers work the same way, but circular polarizers have a layer that UNpolarizes the light after it has done its polarizing job. That way the light continuing into the camera is not polarized and won't be a disadvantage to systems in the camera.

Polarizers reduce light and are fussy things. I think many these days shun their use and just darken skies in post-processing. I have some and hardly ever use them. But for special situations such as shooting through glass or a water surface at an angle, I would use them.

About the only time I use them is for traditional methods macro of plants and fungi that are wet to improve colour saturation.
Probably should use them more, but who has time for that??