A circular polarizing filter cuts glare and reflections from non-metallic surfaces — water, glass, wet leaves, haze — which deepens blue skies, saturates foliage, and lets you see into water.
Rotate the front ring to dial the effect from none to maximum; it’s strongest at 90 degrees to the sun, which is the whole trick to using one. It costs about 1–2 stops of light, and it’s the one effect software still can’t fake, because the reflection is gone before the sensor sees it.
Below are real before/after examples of the effect, how to set it, the situations where it backfires (wide lenses, banded skies, metal), and what to look for when buying — with the basics of the other filters in my beginner’s lens-filter guide and the buying comparison in my polarizing filter shootout.
Polarizer filters can work wonders in spicing up a photo. They can work wonders in cases where cutting through glare will improve contrast and make the colors pop.
By reducing the glare of reflections, they can help peer through transparent reflective surfaces a bit like x-ray vision. They can deepen the blues of a blue sky, and even with black and white, they can add texture to areas that might otherwise have become blown-out highlights.
They’re especially well-suited to outdoor photography because of the way they can counteract the natural glare of sunlight. At the beach, they’ll intensify the color of water, especially when there’s a coral reef or sand not far underneath the surface. They’ll also rescue highlights from bright snow or ice. And even as a general-use tool, they can go a long way to salvaging shooting outdoors in the middle of the day when the sun is at its harshest.
A polarizer can reduce reflections on water, ice, and foliage, but it doesn’t work on metals. That includes chrome and even mirrors, which get their reflectiveness from a metallic backing.
And a true polarizing effect is something that just can’t really be mimicked effectively by post-processing, despite any software filters you see in apps that call themselves polarizers. It is basically unfakeable. Software can darken a blue sky and enrich colors, and some of the newer software (like Lightroom Classic) can even use AI to reduce reflections, but it’s still not nearly as effective as a true polarizer filter that applies even before the light hits the sensor.
There are two elements affecting how much of an effect polarizing filters have. The first is the strength and type of the polarizer filter. Not all polarizers are the same, as you can clearly see in these polarizer filter side-by-side tests.
The other element comes down to lighting conditions, and especially the angle of light. They’re at their maximum strength at 90° to the sun or primary light source, so you’ll get the most effect if the sun at your shoulder (left or right).
A true polarizing effect is basically un-fakeable.
Importantly, the effect reduces the further away from 90°, which can introduce some inconsistent results on very wide-angle lenses because they span a wide field of view — you end up with banding, where parts of the sky are a dark, deep blue and other parts are less so, creating a pretty ugly look.
How to use it: The “90-Degree” rule
A polarizer is not a “set it and forget it” tool. It relies entirely on your angle relative to the sun.
The Golden Rule: The polarizer works at maximum strength when the sun is at a 90° angle to your lens.
- If the sun is behind you: The polarizer will do nothing.
- If the sun is in front of you: The polarizer will do nothing.
- If the sun is at your shoulder: The polarizer is at 100% power.
The “L-Hand” Trick: Make an “L” shape with your hand. Point your index finger at your subject. Stick your thumb straight up. Rotate your hand so your thumb points at the sun. If you can do this, your polarizer will work perfectly.
Real-world examples of the effect of a polarizer filter
To make it easier to visualize the effect, I put together some practical side-by-side examples with before-and-after shots, with and without a polarizer.
These are using some scenes where the polarizing effect really comes into play: clear blue skies, bright highlights, and water.
An added bonus of a polarizer is that it acts as a roughly 1.5-stop neutral density filter, which can be useful for slowing down shutter speeds. That can be considered a light tax by reducing light, but it can also be a positive.
All of these were shot with the same camera and lens combinations. They’re shot at the same ISOs and apertures. The only slight differences in exposure settings are due to the little bit of light drop off that the polarizer adds, so the shutter speeds for the polarizer versions are just a shade slower to compensate.
There’s no additional post-processing–I haven’t applied any extra contrast in editing to the polarized versions, for example. And to make the comparison as close as possible, I’ve synchronized the white balance setting in each pair.
Things to watch out for when using a polarizer filter
There are some things to watch out for when using a circular polarizer filter.
- You’ll lose up to about two stops of light. That’s one reason they can be less useful in marginal lighting conditions. Conversely, they can also be useful if you need to slow down shutter speeds just a touch but don’t want to resort to an ND filter.
- They work best with directional light, ideally at 90° to the sun, and don’t work as effectively outside a certain angle range.
- It Doesn’t Work on Metal. Physics dictates that polarizers only remove reflections from non-metallic surfaces (glass, water, plastic, paint, leaves). If you are trying to remove the glare from a chrome bumper or a silver mirror, the filter will have no effect.
- Unless you’re using something like the Cokin or Lee filter mount system, it means screwing and unscrewing a filter each time you want to use it.
- They don’t work well with most lens hoods.
- You’ll also need to adjust the filter for each shot since it consists of two layers of glass and the outside layer rotates.
- Adding extra layers of glass can increase the chances of lens flare. Ideally, you wouldn’t be shooting directly at light sources with a polarizer anyway, but the modern coated filters do a pretty good job of reducing flaring.
- It’s generally not a good idea to use a polarizing filter when shooting for stitched panoramas. Because the polarizing effect isn’t evenly applied across the frame, if you have blue sky in the frame, you’ll have a lot of trouble avoiding banding across the sky. I’ve put together some examples of why not to shoot panoramas with a polarizer filter.
- The “Blue Blob” on Wide Angle Lenses. Because the polarizing effect relies on a specific angle to the sun, the sky is not polarized evenly. If you use a super-wide lens (wider than 24mm), your lens sees such a massive chunk of the sky that it covers areas that are polarized and areas that aren’t. So it’s best to avoid using polarizers on ultra-wide lenses or to limit them strictly to just removing reflections on the ground, not for the sky.
Common questions
When does a polarizer not work?
On metal (chrome, mirrors), when the sun is directly in front of or behind you, and on very wide lenses, where the sky darkens unevenly across the frame. Cloudy days show little effect.
Linear or circular polarizer?
Circular, for any camera with autofocus and through-the-lens metering — which is every digital camera. Linear polarizers confuse those systems.
Can I leave a polarizer on all the time?
You can, but you lose 1–2 stops and risk uneven skies on wide shots. I put it on for water, foliage, glass, and strong blue-sky days, and take it off otherwise.
What to look for when buying a polarizing filter
- There are two classes of polarizing lenses: circular and linear. If you’re using a DSLR with autofocus or anything that meters through the lens, you want a circular polarizer. Older “Linear” polarizers confuse the beam-splitters inside DSLRs and Mirrorless cameras, causing your autofocus to hunt and your auto-exposure to be inaccurate.
- You need to get the size that matches the thread diameter of your lens. If your lens has a 77mm diameter (usually marked on the lens itself in the form of ∅77), you’ll want a 77mm polarizer. To avoid buying multiple polarizer filters, you can buy one with the largest diameter of your lenses and using step-up rings (which are much cheaper).
- If you’re really serious about your filters, you can also get polarizers for Lee and Cokin plate filter systems (with holders) that are more forgiving of lens diameter.
- With very wide-angle lenses, adding what amounts to extensions onto the end of the lens risks vignetting in the corners of the frame. Buying polarizing filters designated as slim filters (aka low-profile filters) reduces that risk, although they are often more expensive.
Lens filter size charts
I’ve compiled some lens filter size charts, starting with some of the most commonly used and current lenses. You can find the corresponding chart here:
