Ring’s digital zoom is also excellent, and the bumped-up siren is the loudest I tested (at 110dB, 105 on the Plus). You can’t trigger the siren on motion, but there is the option to add a verbal warning telling prowlers they’re on camera — less offensive to the neighbors than a motion-triggered siren. I also like the option of a version that runs off a standard wall outlet if you don’t have a junction box available, but I recommend hardwiring if you can.

All of these features are part of the Google Nest Cam that magnetically attaches to the two floodlights. The lights have good control options, including adjustable arms to angle your lighting, app, and voice control in the Google Home app, ambient light activation, and the option to dim the beams.

That lighting control includes adjusting the brightness (handy if you have sensitive neighbors), the length of time the lights stay on, what activates them, the option to have lights come on automatically at sunset and turn off at sunrise, and even integrate into smart home routines. Some models have lights that can be controlled individually with voice assistants such as Alexa, Google, and Siri, using their respective platforms.

Polarizer examples

Despite the camera’s smaller size, the light is very bright and more than enough to illuminate my entire back patio. It’s one of only two cameras I tested that has the option to pulse its light to scare off intruders, and you can set its 80dB siren to go off on motion. (Be careful with this feature if you don’t want your neighbors to come knocking.)

In order to select a specific polarization of light, polarizers are used. Polarizers can be broadly divided into reflective, dichroic, and birefringent polarizers. More detailed information on which type of polarizer is right for your application can be found in our Polarizer Selection Guide.

Compared to my previous budget pick, the Wyze Cam Floodlight V1, the Blink has a cleaner design and doesn’t force a five-minute cool-down period between recordings, which the Wyze does if you don’t pay for a subscription. The V1 has been replaced by the Wyze Cam Floodlight V2, which I have yet to test. This adds 2K HD video, a wider field of view, and 2,800 lumens of light for around $10 less than the Blink. The original V1 is currently on sale for $54, a real bargain. But overall, I prefer the Blink. See Other outdoor floodlight cameras I tested for more on Wyze.

You can store recorded video locally, but you need a $35 Sync Module and a USB stick. If you pay for cloud storage, you’re allowed up to 90 minutes of continuous livestreaming, with the option to record a live view. Person detection was largely accurate, although it often mistook my 80lb dog for a person (fair enough?). I like that you can set the camera to only record when it sees a person, which helps cut down on clip clutter.

The Wyze Cam Floodlight Pro ($150) is an upgrade to my previous budget pick, the Wyze Cam Floodlight V1, and it’s better all around, with higher lumens, tunable light, higher resolution (2.5K), and a wider field of view (180 degrees). It’s also more expensive but uses AI-powered light control that can be set only to turn the lights on when a person or vehicle is detected. The video quality is impressive at this price, and its AI-detection accuracy has improved since I started testing it. But the Reolink camera offers the same field of view and higher video resolution and keeps all of its recordings completely local. Considering Wyze has had some security issues that might give you pause before purchasing one of its cameras, there are better options.

In Figure 5, a linear polarizer was placed in front of the lens in a machine vision system to remove obfuscating glare such that an electronic chip could be clearly seen. The left image (without polarizer) shows randomly polarized light scattering off of the many glass surfaces between the object and the camera sensor. Much of the chip is obscured by Fresnel reflection of the unpolarized light. The image on the right (with polarizer) shows the chip without glare obscuring any of the object details, allowing the chip to be viewed, analyzed, and measured without obstruction.

A helpful auto-cruise feature let me set four preset positions and have the camera auto-rotate through them on a set schedule or on demand. A Look Around button on the main page of the Eufy app sends the camera into a surveillance spin for a quick check over my property.

When something goes bump in the night in your backyard, you probably want to know about it. While regular security cameras with night vision can show you what’s out there, a floodlight camera can show you and tell that rascal or raccoon to get off your lawn, scaring them away with some powerful lumens and possibly a blaring siren.

Video quality: 2K /  Lumens: 3,000 / Smart alerts: Person, can add animal, vehicles, packages and facial recognition with a hub / Field of view: 360 degrees (270 motion) / Siren: 100 decibels / Power options: Hardwired / Wi-Fi: 2.4GHz / Storage: Local (on-device or hub), cloud / Subscription fee: $3 monthly — not required / Works with: Amazon Alexa, Google Home

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The Pro 3 Floodlight Cam doesn’t require an Arlo hub, but it can be used with one to help with range and extend battery life. If you want Apple Home compatibility, you need that hub, which costs $100. Unfortunately, it doesn’t have HomeKit Secure Video or local storage. There is no way around that Arlo subscription, which keeps getting more expensive.

Many different types of microscopy techniques such as differential interference contrast (DIC) microscopy utilize polarizers to achieve a variety of effects.

Floodlight cameras cost between $99 and $250 and generally come with the same camera technology as standard outdoor cameras. The Google Nest Cam with floodlight, the Arlo Pro 3 Floodlight, and the Ring Floodlight Cam Pro all essentially take the companies’ flagship cameras and stick 2,000 to 3,000 lumens of motion-activated light on them. The camera is controlled in the same way and with the same features as the regular outdoor camera, but you get the added option of light control, making this an excellent upgrade to standard motion-activated lighting and to standard security cameras.

A more budget-friendly option for a wireless outdoor floodlight camera is the $130 Blink Outdoor 4 Floodlight Camera. I’ve not tested it yet, but it has the same software features as the Blink Wired Floodlight Camera (including local storage and person detection) and the same 143-degree field of view. It promises up to two years of battery life on two AAs (the floodlights run on four D-cell batteries) but only delivers 700 lumens of light.

Ring light guides are popular illumination sources due to their even, diffuse illumination. However, glare or reflection of the ring itself may occur. Polarizing the ring light output and the lens separately can reduce these effects, and bring out surface details as seen in Figure 9.

Molecular compounds that have the same type and number of atoms, but different molecular arrangements are called stereoisomers. These stereoisomers are “optically active” and will rotate polarized light in different directions. The amount of rotation is determined by the nature and the concentration of the compound, allowing polarimetry to detect and quantify the concentration of these compounds. This is the premise for identifying which stereoisomer may be present in a sample, which is important because stereoisomers can have vastly different chemical effects. For example, the stereoisomer limonene is the chemical that gives oranges and lemons their characteristic scents.

Where θ is the angle between the incident linear polarization and the polarization axis. We see that for parallel axes, 100% transmission is achieved, while for 90° axes, also known as crossed polarizers, there is 0% transmission. In real-world applications the transmission never reaches exactly 0%, therefore, polarizers are characterized by an extinction ratio, which can be used to determine the actual transmission through two crossed polarizers.

The enhanced motion detection is the main reason to buy the Pro model over the Floodlight Cam Wired Plus, which is $50 cheaper. The other key differences are no HDR imaging on the Plus or the option of 5GHz Wi-Fi. Neither of these makes much difference on a floodlight camera — due to its likely location being up high and far away from your Wi-Fi router — but better motion detection is worth a lot on a security camera.

Eufy has a newer pan and tilt floodlight camera — the E340 — that you can buy with a HomeBase for $370 ($220 without). This one mounts to a wall, not under an eave, and has one less light panel for a maximum of 2,000 lumens. It offers 5GHz Wi-Fi and works with a microSD card (the Pro 2 has fixed onboard storage) and the HomeBase, giving you a bit more flexibility. It also offers 24/7 recording, which the Pro 2 doesn’t. I’ve not tested this yet, but if those features are important to you, it could be a better option.

Birefringent polarizers rely on the dependence of the refractive index on the polarization of light. Different polarizations will refract at different angles and this can be used to select certain polarizations of light.

One issue I ran into was water getting into the floodlight after a heavy rainstorm. I was able to dry it out, and it’s been working fine since then, but I would recommend installing this — and any floodlight camera — under an eave or some covering where possible to extend its life.

The Blink Wired Floodlight Camera ($99.99) is a good budget option with on-device processing of people alerts, so nothing has to go to the cloud (although you have to subscribe for this feature). It offers local storage and 1080p video and works with Amazon Alexa for smart home control.

Reflective polarizers transmit the desired polarization while reflecting the rest. Wire grid polarizers are a common example of this, consisting of many thin wires arranged parallel to each other. The light that is polarized along these wires is reflected, while light that is polarized perpendicular to these wires is transmitted. Other reflective polarizers use Brewster’s angle. Brewster’s angle is a specific angle of incidence under which only s-polarized light is reflected. The reflected beam is s-polarized and the transmitted beam becomes partially p-polarized.

Light is an electromagnetic wave, and the electric field of this wave oscillates perpendicularly to the direction of propagation. Light is called unpolarized if the direction of this electric field fluctuates randomly in time. Many common light sources such as sunlight, halogen lighting, LED spotlights, and incandescent bulbs produce unpolarized light. If the direction of the electric field of light is well defined, it is called polarized light. The most common source of polarized light is a laser.

By Jennifer Pattison Tuohy, a smart home reporter who’s been testing connected gadgets since 2013. Previously a contributor to Wirecutter, Wired, Dwell, and US News.

A Google Nest Cam attached to two bright, adjustable floodlights, this camera has free video recording, powerful lights, and on-device processing of smart alerts for people, vehicles, and animals. There’s no siren, but there is 24/7 recording and facial recognition. Read our review.

I tested the Wi-Fi version, but if you’re set up for it there is the option of power over ethernet. The Wi-Fi version comes with a standard power brick and the option to connect it via ethernet for a more stable connection. This does means it can’t easily be wired in place of existing lighting, though, and you need an outlet nearby. It also only mounts horizontally to the side of a house, not vertically under the eaves.

Wiring for a floodlight camera is similar to any lighting fixture, with the addition of an outdoor junction box in some cases. I highly recommend employing an electrician, especially if you are uncomfortable fiddling with wiring while on top of a ladder.

The lights make a floodlight camera more useful than a standard security camera, so high lumens for security (2,000 or more) and the ability to adjust brightness and to control the lights is essential. Tunable white light that can change from cool to warm tones is a bonus, as the lights can double as ambient lighting. The option to have the lights turn on automatically from dusk to dawn is a nice-to-have feature, too.

I also find the Arlo app to be finicky. It logs me out frequently and takes ages to pull up a live view. In comparison, I didn’t have the same issues with the Ring app — despite the camera being installed further from my router than the Arlo (Amazon’s Sidewalk network is lending a helping hand here).

The same phenomenon can be seen in the Figure 6. In the left image (without polarizer), unpolarized light from the sun is interacting with the windows of the Edmund Optics building and most of this light is reflecting off the windows. In the right image, a polarizing filter has been applied such that the reflected light, rich in one polarization type, is being blocked from the camera sensor and the photographer, using the other polarization type, can see into the building more easily.

While there’s mixed research on whether outdoor lighting is a significant crime deterrent or just potentially annoying for your neighbors, there are plenty of benefits to lighting up your property from a safety and security perspective.

The Reolink Duo Floodlight camera lacks a few bells and whistles — there are no rich notifications, HDR imaging, tunable white light, or fancy features like zoom and track. That said, it records all video locally, and there’s no cloud connection at all. This means no subscription fees. It has on-device processing for alerts for people, vehicles, and animals, and its huge 180-degree field of view easily covered my entire half-acre backyard.

Anyone considering installing security cameras outside their home should look at a floodlight camera first. These devices combine lights, a camera, and (in most cases) continuous power in one easy package. The motion-activated lights also provide a valuable safety feature, helping make sure you don’t trip on that package left in your driveway. Plus, most have built-in sirens you can activate to deter anyone from creeping around your property.

There is no built-in siren or 24/7 recording, and you have to pay for an iCloud Plus plan (starting at 99 cents per month) to view any recorded video. But there is two-way audio, which is very good, and you can use the light and motion sensors separately to trigger automations in the Apple Home app.

Video quality: 4K (2K each camera), 10x digital zoom /  Lumens: 2,400 / Smart alerts: People, vehicles, animals / Field of view: 180 degrees / Siren: Yes / Power options: POE or plug-in / Wi-Fi: 2.4GHz and 5GHz / Storage: Local only / Subscription fee: none / Works with: Google Home, Home Assistant

It’s available in white or black and can fit under the eaves or be mounted on the side of a wall. The floodlight lights are easy to manually adjust and very bright (2,600 lumens). While you can adjust the brightness, the white isn’t tunable. You can set them to turn on automatically at dusk and off at dawn.

With a microSD card installed or a connection to a Reolink NVR, the camera can record continuously and be set to do so on a schedule. Using the app, you can schedule times for specific motion detection, such as “only alert me to people at night.” It’s the only camera I tested with a timelapse feature that you can also schedule, and this was fun for capturing a sunset or catching my dog dashing around my yard.

Another issue is that the audio quality is very staticky (a problem with all Blink cameras I’ve tested), but the siren is clear and loud. Motion alerts came in instantly, but pulling up the live view could take a while. I liked that I could set an Echo speaker to announce when motion was detected and see a live view on an Echo Show smart display.

Important note: In 2022 Eufy suffered some security vulnerabilities, which the company was not transparent about. We temporarily removed our recommendations while the company worked on a fix. While the security flaws appear to have been resolved, the company’s lack of transparency is something to consider before purchasing a Eufy camera. You can read more about the issues and Eufy’s solutions here.

The camera works with the Google Home app (not the old Nest app) and can stream to both Google Nest and Amazon Echo smart displays. It doesn’t fit well for an under-the-eave installation (as you can see in my pictures), so only consider it if you can install it on the side of your house and up high.

The downside to floodlight cameras is they’re significantly more expensive than their non-shiny siblings, generally $100 or so more. They’re also more limited in where you can place them; most need to be up high and where there is existing wiring for lighting (unless you are ready to spend a few extra hundred dollars on an electrician’s services). But that wiring provides continuous power, so you don’t have to mess with them once they’re up. The same can’t always be said for battery-powered options.

I like that I could adjust the sensitivity of each motion sensor and set up activity zones to limit false alerts. Opt-in rich notifications preview the captured clip right in your phone’s notification tray, reducing how often I had to open the app to check in.

Unpolarized light can be considered a rapidly varying random combination of p- and s-polarized light. An ideal linear polarizer will only transmit one of the two linear polarizations, reducing the initial unpolarized intensity I0 by half,

Polarization control is also very important in the chemical, pharmaceutical, and food and beverage industries. Many important organic chemical compounds, such as active pharmaceutical ingredients or sugars, have multiple orientations. The study of molecules with multiple orientations is called stereochemistry.

The advantage of hardwiring is there are no battery-charging woes. And unlike a plug-in camera, you don’t need to worry about drilling through your walls to access an indoor plug or putting the camera near an outdoor receptacle while snaking wiring down the side of your house. If you already have some outdoor lighting, it’s a relatively easy swap to get a hardwired, always-on security camera plus light set up on the side of your house.

The Eufy Floodlight Cam 2 Pro has a 360 field of view and super bright, tunable LED floodlights. There are no monthly fees for viewing recorded footage, but the limited zoom and spotty smart alerts let it down.

What are polarizersused for

It’s also got facial recognition if you take the time to add known faces. It’s a lot nicer to get an alert that says, “Sarah the Gardener is in the backyard,” rather than the scarier “There’s a person in the backyard.” You need to pay for a Nest Secure subscription service for this, which starts at $8 a month.

Without a HomeBase, there is 4GB of nonremovable onboard storage for around 14 days’ worth of recordings. You can also use a network-attached storage setup or Eufy’s cloud service for $3 a month per camera. There is no 24/7 continuous video recording, and it works with Google Home and Alexa to stream footage on smart displays and control the camera’s lights in the app.

Video quality: 2K, 12x zoom / Lumens: 2,000 (3,000 when plugged in) / Smart alerts: Person, package, vehicle, pet ($) / Field of view: 160 degrees (130 motion) / Siren: Yes (105 decibels) / Power options: Battery, solar panel, plug in / Wi-Fi: 2.4GHz / Storage: Cloud / Subscription fee: $7.99 monthly / Works with: Alexa, Google Home, Apple Home, Samsung SmartThings

Polarizer Filter

Video quality: 1080p HD, 8x digital zoom / Lumens: 2,000 / Smart alerts: Person ($) / Field of view: 140 degrees (270 motion) / Siren: Yes (110 decibels) Power options: Hardwired or plug in / Wi-Fi: 2.4GHz and 5GHz / Storage: Cloud, local / Subscription fee: $4.99 a month / Works with: Alexa, SmartThings, Ring

The Eve Outdoor Cam is a compact floodlight camera that mounts to a wall. With good-quality video and two-way audio, it doesn’t have a siren but is a good option for Apple’s HomeKit Secure Video, which adds alerts for people, packages, animals, and vehicles as well as facial recognition.

But the Arlo is a battery-powered camera, and while this means you can mount it anywhere you need to, it lacks the best feature of hardwired floodlight cams: reliable, continuous power. Arlo has the option of continuous power, but you need a nearby outlet and an additional $50 power cord. It does not mount to a standard outdoor junction box and isn’t a great drop-in upgrade for an existing non-camera floodlight. I tested the Arlo for six months on battery power in a very busy location and had to charge it every two months. A $60 solar panel add-on would help, but then you’re paying over $300.

Unstressed clear objects between crossed polarizers should yield a completely dark field, however, when internal material stress is present, the localized changes in refractive index rotate the angle of polarization, resulting in transmission variations.

The camera works with Ring’s app and its extensive security system, but the only other smart home platform it’s compatible with is Amazon Alexa and Samsung SmartThings (which lets you view a live stream on your Samsung TV). Alexa integration is useful; you can view a live feed in the Alexa app and on Alexa-enabled smart displays and have Echo smart speakers announce when people and / or motion is detected. But you can’t control the Ring’s floodlights through Alexa, either with voice or in routines; you have to use the Ring app for all light controls.

Once the analyzer has been aligned perpendicularly to the polarizer, an anisotropic, or birefringent, the specimen is placed on the specimen stage. The specimen rotates the polarized light a designated amount, proportional to the specimen thickness (and thus the optical path distance) and the specimen birefringence, before its light reaches the analyzer.

Video quality: 1080p HD, 6x digital zoom /  Lumens: 2,400 / Smart alerts: People, vehicles, animals, familiar faces ($), sound ($) / Field of view: 130 degrees (180 motion) / Siren: No / Power options: Hardwired, plug-in ($) / Wi-Fi: 2.4GHz and 5GHz / Storage: Cloud and local / Subscription fee: $8 a month / Works with: Alexa, Google, Samsung SmartThings

The Ring Floodlight Cam Wired Pro delivers high-quality video with adjustable, accurate radar-powered motion detection, 2,000 lumens of light, and a good digital zoom. It offers smart alerts for people or motion and works with Amazon Alexa, Samsung SmartThings, and Ring’s excellent app.

However, the app is complicated and fiddly to set up, the siren is very quiet, and there are limited smart home integrations, but it can connect to Google Home and Home Assistant and has a desktop app.

Polarizer film

But it is ugly. And the outdated push-to-talk two-way audio (we’d love some full-duplex here), limited zoom, and no option for continuous video recording are all letdowns.

Its video quality is very good, especially during the day. Images were bright, clear, and only a little pixelated when I zoomed in. With the light on, the image was a little muddy at night, but I could make out faces clearly. The regular night vision was slightly better.

In a simple polarization microscope system, a linear polarizer is placed in front of a microscope light source, below the specimen stage, to polarize the light entering the system. Another linear polarizer placed above the specimen stage is referred to as an “analyzer,” as this polarizer is rotated to achieve the desired effect when analyzing the sample and while the first polarizer is kept stationary. The analyzer is then rotated such that the polarization planes of the analyzer and polarizer are 90° apart. When this has been achieved, the microscope has a minimum transmission (crossed polarizers); the amount of light transmission will be proportional to the extinction ratio of the polarizer and analyzer.

The Arlo Pro 3 Floodlight Cam has excellent video quality, versatile installation options, and the widest smart home integration — Amazon Alexa, Google Home, SmartThings, and Apple Home. It’s expensive, especially when you add continual power and pay for smart alerts and video recording.

The Eve camera is compact, svelte, and the smallest camera I tested. It was so small it didn’t completely cover the electrical box for the light it was replacing. (It only mounts on a vertical wall, so you can’t put it under an eave or overhang.) It has a good solid feel and the housing is aluminum (all the other models in this guide are plastic), and it comes in white or black. The Eve Outdoor Cam also looks much less like a mall surveillance camera than many of its competitors.

The camera also has a narrow field of view (122 diagonal) compared to the Reolink (180), and its AI detection is spotty, frequently telling me my cat was a vehicle. (Smokey is smooth, but not that smooth.) While the Lorex has some better features and a better app, the Reolink has a wider field of view and higher video quality, which makes it easier to recommend for most people.

If you don’t have access to hardwiring or a nearby power outlet, or you want a floodlight camera that works with all the major smart home platforms, the Arlo Pro 3 Floodlight Cam is the best option. This camera works with Google Home, Samsung SmartThings, Apple Home, and Alexa. It has better video quality than the Ring, a 12x digital zoom, an option to auto-track and zoom, a motion-activated siren, and more smart alerts.

However, until early 2023, Lorex was owned by Dahua, a company on the US government’s economic sanctions list (meaning the US government won’t allow these to be used in government projects or facilities). Lorex was recently sold to a Taiwanese company, but US lawmakers claim that Lorex devices still pose a potential risk to US consumers. It’s hard to tell how much of it is geopolitical games and how much is a legitimate concern. Lorex told us all its “products marketed in the U.S. are authorized by the FCC ... for consumers and private sector business customers” and pointed us to this statement about its supply chain.

In the Ring app, you can adjust the three motion zones for the lights — which is handy for preventing them from turning on when my neighbor walks in his yard. The lights can also be set on a schedule, adjusted in brightness, and linked with Ring devices so that if a Ring camera on one side of the house detects motion, it can turn on the floodlights on the other.

While polarizers select certain polarizations of light, discarding the other polarizations, ideal waveplates modify existing polarizations without attenuating, deviating, or displacing the beam. They do this by retarding (or delaying) one component of polarization with respect to its orthogonal component. To help you determine which waveplate is best for your application, read Understanding Waveplates. Correctly chosen waveplates can convert any polarization state into a new polarization state and are most often used to rotate linear polarization, to convert linearly polarized light to circularly polarized light, or vice versa.

Like a light fixture, floodlight security cameras generally hardwire to your electrical system. They still operate wirelessly to transmit video using your home’s Wi-Fi. Some have a backup battery built-in, and one I tested (the Arlo Pro 3 Floodlight camera) can be completely wireless, working just off battery.

While I didn’t find the Bird’s Eye View feature that useful, the radar-powered 3D motion detection was very good. Of all the cameras I tested, this was the most reliable at picking up motion anywhere in its range, even mounted on the eave of my second floor. A nice feature that no other camera I tested offers is offline alerts. It can tap into Amazon’s Sidewalk network to send notifications even when your Wi-Fi is out. I couldn’t view a video feed from the notification when my internet was down, but I did know something had happened and could go back to view the event once connectivity was restored.

Ring’s top-of-the-line wired floodlight camera has superb video quality, excellent motion detection, and an impressive 2,000 lumens of adjustable light. Its wide horizontal and deep vertical field of view gave a better vantage over my backyard than most of the competition. It’s my favorite of all the cameras I tested, and it’s also the best floodlight camera that works with Amazon Alexa.

But there is no built-in siren, making it a poor choice for a dedicated security device. It offers 5GHz Wi-Fi, and the on-device machine learning makes for speedier notifications than most cameras I tested. Motion sensors in the floodlights provide a wide 180-degree sensing range, ensuring the lights turn on when anything gets nearby.

Examples ofpolarizersin Physics

1080p HD video is the minimum video quality; higher is better, as you’ll want to zoom in. Most floodlight cameras are up high, so a good zoom will help show details like faces.

Eufy has gone for function over form with its beast of a floodlight camera that boasts a 360-degree field of view that pans and tilts to cover a vast area. This feature — plus its three adjustable, tunable lighting panels, individually addressable PIR motion sensors, and free local storage — makes the Eufy Floodlight Cam 2 Pro a great option if you have a large area to cover.

Another consideration is that most floodlight cameras use non-replaceable LED lighting, so you’re left with a camera in the dark if the lights go bad. A couple of models — Nest and Wyze — have removable cameras, so if the lights do go out, you still have a camera you can use elsewhere. All models I tested have lights that should last between 50,000 and over 100,000 hours of use.

Video quality: 1080p HD, 6x digital zoom / Lumens: 2,400 / Smart alerts: People, vehicles, animals, familiar faces  / Field of view: 157 degrees / Siren: No / Power options: Hardwired / Wi-Fi: 2.4GHz / Storage: Cloud / Subscription fee: $1 a month (for iCloud+) / Works with: Apple Home

The Reolink has two separate 2K lenses for a whopping 180-degree field of view and combined 4K video. It has no cloud connection and records locally to a microSD card, FTP, or NVR. On-device person, pet, and vehicle detection are free. However, its app has a steep learning curve, there are no advanced features like track and zoom, and it has limited smart home integrations.

Before installing, download the manufacturer’s app and check the instructions. Some cameras must be paired to the app before mounting them, which helps avoid too many trips up a ladder.

I was impressed with the Lorex 2K Wi-Fi Floodlight Security Camera ($249) with its clear 2K video, loud siren, and free smart alerts for animals, vehicles, and people. There’s no cloud component (it records locally to an included microSD card) and no monthly fees. It also has a handy track and zoom feature, adjustable light temperature, rich notifications, and a more user-friendly app than the Reolink (my pick for the Best floodlight camera without subscription fees).

The two orthogonal linear polarization states that are most important for reflection and transmission are referred to as p- and s-polarization. P-polarized (from the German parallel) light has an electric field polarized parallel to the plane of incidence, while s-polarized (from the German senkrecht) light is perpendicular to this plane.

Here, I’ve rounded up the best outdoor floodlight security cameras based on extensive testing over two years at a single-family home in South Carolina.

You’ll need to pay for a Ring Protect Plus plan for recorded video, starting at $4 a month, and increasingly a bargain as every other smart home company raises its subscription prices (I’m looking at you, Arlo and Nest). This also adds person detection (no other smart alerts) — without it, it’s live stream only. However, the Pro does work with local storage using a Ring Alarm Pro.

The 2K video quality is good, although the digital zoom is lacking. The camera works over 2.4GHz Wi-Fi, has a weather rating of IP65, and includes standard and color night vision. It doesn’t require a Eufy hub but can work with the Eufy HomeBase 3 for added features and storage, which adds AI-powered smart alerts — including animals and vehicles, plus facial recognition. I’ve not tested this feature yet, and the HomeBase costs $150 but will work with multiple Eufy cameras.

The angular difference between the axes of polarization of the two polarizers is directly related to the amount of overall light attenuation of the set of polarizers. By changing the angle offset, the optical density of the polarizer set can be varied, achieving a similar effect to using a neutral density filter. This ensures that the overall field is evenly illuminated.

The ideal place to install a floodlight camera is facing a yard, path, or driveway, placed up high — at least six to 10 feet — so the lights cover an ample space and the camera has a good view. Make sure you have decent Wi-Fi in the area you want to install; if not, consider extending your Wi-Fi or upgrading to a mesh router.

Hot spots are highly reflective portions of a field within a more diffuse reflecting field. In Figure 8, a polarizer is placed in front of the lens of a camera as well as over the light source illuminating the scene to reduce hot spots.

Polarizer material

The Eve Outdoor Cam is the best Apple Home-compatible outdoor floodlight camera. It works with HomeKit Secure Video, which processes all video locally on an Apple TV or HomePod. But it’s only compatible with the Apple Home and Eve app, which doesn’t have an Android version yet, so only get this if you use an iPhone.

Lights and sirens are a good deterrent to a potential intruder, although be wary of turning on a siren automatically based on motion unless you really don’t like your neighbors. Some models offer an automated voice alert option; two-way audio lets you speak to anyone prowling your property.

Edmund Optics® offers a wide variety of polarizers, waveplates, polarizing beamsplitters, and other polarization-manipulating optics.

Another characteristic way to see how polarizers reduce reflective glare is by viewing water surfaces. In Figure 7, the surface of the water appears reflective in the left image, obscuring what is below the surface. On the right, however, the rocky debris on the floor of the body of water is much more clearly visible.

Like security cameras, a floodlight camera should be able to distinguish between people and motion. Animal, vehicle, and package detection is a plus. A useful upgrade is a camera that can turn its lights on only when it detects specific objects.

In amorphous solids such as glass and plastic, stress from temperature and pressure profiles in the material imparts localized variations and gradients in the material properties, making the material birefringent and nonhomogeneous. This can be quantified in transparent objects using the photoelastic effect, as stress and its related birefringence can be measured with polarized light methodologies.

Implementing polarization control can be useful in a variety of imaging applications. Polarizers are placed over a light source, lens, or both, to eliminate glare from light scattering, increase contrast, and eliminate hot spots from reflective objects. This either brings out more intense color or contrast or helps to better identify surface defects or other otherwise hidden structures.

A floodlight camera has a few benefits over a standard smart security camera. If you have existing hardwired lighting around your home, it’s an easy swap to add a camera and lighting in place of outdoor lights. This removes worries about recharging batteries, installing solar panels, or taking up an outdoor outlet. If you’re looking for advice on why you might want a floodlight camera or how to install it, I’ve got more details for you below, as well as tips on how to install a floodlight camera.

The camera comes with smart alerts for people out of the box, but you can connect it to a Eufy HomeBase 3 ($150) for animals, vehicle, and package alerts, and facial recognition, all processed locally on the hub; this also adds more storage.

There is a lot to like about the Google Nest Cam with floodlight. It has built-in battery backup for when the power goes out, free on-device recording (up to three hours), free smart alerts for people, animals, and vehicles, and the option of 24/7 recording (for a fee).

By cross-polarizing light with two linear polarizers that are oriented perpendicularly, hot spots can be reduced or eliminated altogether.

How dopolarizerswork physics

The Arlo is the least obtrusive-looking floodlight camera I tested. I won’t go so far as to say it looks nice — but it’s not as large or as prominent-looking as the rest (with the exception of the Eve Outdoor Cam).

For linearly polarized light with intensity I0, the intensity transmitted through an ideal polarizer, I, can be described by Malus’ law,

With 1080p video, 2,600 lumens, and a 105dB siren for under $100, this is a good budget buy. You sacrifice better video quality and tunable lighting over other options. The Blink app is clunky and the audio isn’t great, but there’s person detection (with a monthly fee) and local recording (with additional hardware). It integrates with Amazon Alexa, has a nice design, and can be mounted horizontally or vertically.

The analyzer only transmits light that has experienced a specimen-induced phase shift and continues to block all the unaffected light from the source which was originally polarized by the polarizer. If the birefringence of the specimen is known, it can then be used to determine the specimen thickness. If the specimen thickness is known, it can be used to deduce the birefringence of the specimen. A convenient chart used for this purpose is known as the Michel-Levy interference color chart in Figure 14.

The 360-degree pan and tilt feature is well thought out, with subject lock and tracking that follows a person as they walk through your property. While you set the camera to a fixed point, it can detect motion outside its view (thanks to PIR motion sensors in each floodlight panel) and swivel the camera to catch it.

Apple’s HomeKit video integration adds a slew of smart alerts, including people, packages, animals, and vehicles. You can also grant access to your Apple Photos library and get alerts when it recognizes people. Facial recognition and package alerts make this a good camera to set up by your front door. It’s also not super bright, as in it won’t blind visitors. But it will light up the scene well enough to see what’s happening. A brightness boost mode adds an extra bump for 30 seconds if you want a stronger floodlight. It’s nothing compared to the Eufy though, which is like walking down an airport runway.

The video quality, day and night, is good for this price, but the motion detection is limited to about 20 feet. Also, if you don’t pay Blink’s monthly subscription ($3), you can only view a live stream for five minutes in the Blink app. Person detection is also locked behind the paywall even though it’s processed on the device.

Another thing to be aware of is which light switch in your home controls the camera. If you install it where there was previously a light, it will be controlled by a switch somewhere in your home. I wouldn’t recommend covering it with a flat plate or disabling it because it’s a helpful troubleshooting tool if you run into any issues.

Figure 11 shows a photo taken of Edmund Optics Headquarters and the variation in the color of the sky, grass, and foliage from using or not using a polarizer in front of a camera lens. Because electrons in air molecules scatter light in many directions, the appearance of the sky without a polarizer is a lighter shade of blue, as seen in the left image (without polarizer). Additionally, the surface of leaves of trees and on blades of grass are very slightly reflective. Using a polarizer filters out some of the light reflected from these surfaces, darkening the perceived color of these surfaces.

A neat feature is three lighting panels that deliver a blinding 3,000 lumens of light at up to 5,700 Kelvins, much higher than any competitor. At full brightness, it resembles the lighting of a prison yard, which is not great for most people. Thankfully, you can change the brightness and the color temperature from cool to warm. I set it to warm, and 20 percent brightness and it was more than bright enough without being harsh.

If you add a Ring Alarm or Ring Alarm Pro to your setup and pay for the $20 monthly Ring Protect Pro plan, you also add the option of local storage, internet backup, and professional monitoring.

With smart floodlight cameras, you get the added value of better lighting plus a way to keep an eye on your home. Thanks to sensors, artificial intelligence, and machine learning, smart floodlight cameras can be set only to light up when there’s someone there instead of just when a gust of wind sends a plastic bag through your yard.

Most cameras use PIR motion sensing, but radar detection is a nice upgrade; it’s more accurate based on my testing. The lights should have an independent motion sensor, separate from the camera, to help trigger them before the camera so you get a well-lit view. Speaking of view, a wide field of view is important; one well-placed floodlight camera with a wide view (140 degrees or more) can replace the need for two or three standard cameras.

What are polarizersin physics

Video quality: 1080p HD /  Lumens: 2,600 / Smart alerts: Person, package, vehicle, animal ($) / Field of view: 143 degrees / Siren: 105 decibels / Power options: Hardwired / Wi-Fi: 2.4GHz / Storage: Cloud and local (with $35 Sync Module) / Subscription fee: $3 monthly or $30 a year / Works with: Alexa

Understanding and manipulating the polarization of light is crucial for many optical applications. Optical design frequently focuses on the wavelength and intensity of light, while neglecting its polarization. Polarization, however, is an important property of light that affects even those optical systems that do not explicitly measure it. The polarization of light affects the focus of laser beams, influences the cut-off wavelengths of filters, and can be important to prevent unwanted back reflections. It is essential for many metrology applications such as stress analysis in glass or plastic, pharmaceutical ingredient analysis, and biological microscopy. Different polarizations of light can also be absorbed to different degrees by materials, an essential property for LCD screens, 3D movies, and glare-reducing sunglasses.

This is thanks to its two lenses (hence “duo”), each with 2K video quality (4608 x 1728 p). While there’s a weird wobbly effect to the image, possibly due to how it stitches together the two images, the overall quality is excellent, and the lights are bright and responsive to motion.

The camera’s software features are also expensive. You must subscribe to its Arlo Secure service ($7.99 monthly for a single camera or $13.99 for multiple) for zoom and track, rich notifications, and smart alerts for animals, vehicles, and packages. I couldn’t even snooze motion alerts without a subscription plan. There is the option of continuous 24/7 recording for an additional fee.

Dichroic polarizers absorb a specific polarization of light, transmitting the rest; modern nanoparticle polarizers are dichroic polarizers.