This doorbell captures clear audio and video, sends fast alerts, and offers free and paid cloud storage—including an option for 24/7 recording.

What is barrel distortionin photography

For a multi-element lens assembly distortion will usually be positive or negative, but it may not be linear across the image. One should also be aware that the level of distortion may change as working distance changes and is dependent on wavelength.

Although this model has color night vision, I found it to be grainier than other models we tested—and turning it on drained the battery faster. I recommend relying on the camera’s standard black-and-white night vision, which delivers a better picture.

In the F-Theta lens system, the actual image height is designed to satisfy the relation of ?∙?, which is smaller than the ideal image height ?∙???? in a conventional camera lens system. Because the optical system cannot completely correct all the aberrations, f-Theta lens cannot fully meet the linear relationship. F-theta distortion, which describes the relative deviation of the actual image height y from ?∙?, is defined as

Lens distortion is a cosmetic-type optical aberration which does not decrease the amount of information in an image. It occurs when information is displaced geometrically, and while it changes the shape of an image will not result in image blur.

Pincushiondistortionphotography

Wirecutter is the product recommendation service from The New York Times. Our journalists combine independent research with (occasionally) over-the-top testing so you can make quick and confident buying decisions. Whether it’s finding great products or discovering helpful advice, we’ll help you get it right (the first time).

You should occasionally clean your Wi-Fi cameras to keep them free from dead bugs, water stains, and other debris that might alter their function.

The Eufy IndoorCam C120 captures 2K images day and night, a massive upgrade from 1080p resolution, which has long been considered the gold standard. It can detect motion, tell the difference between people and pets, and even hear crying. You can store clips in one of four ways, including locally on a microSD card or NAS (network-attached storage, which you can set to capture just motion-triggered events or to record everything 24/7) and in the cloud via a paid subscription to Eufy Cloud or Apple HomeKit Secure Video. The C24 is also the least expensive, best-performing camera we’ve reviewed that supports Amazon Alexa, Apple Home, and Google Home.

The Google Nest Doorbell was the most accurate when it came to identifying types of motion (person, animal, vehicle, or package), and reacted quickly when sending smartphone alerts and displaying live views. The image resolution is only 960×1280, which is lower than our other picks, but the picture is clear, and the low-res actually ends up being easier on your Wi-Fi network to allow for smoother streaming. Audio was always clear on either end, with adjustable volume and the ability to switch off the microphone when necessary. While it offers free cloud storage, you’ll only be able to access footage from the past 3 hours . If you want to keep it longer, the Nest Aware plan (starting at $8 per month or $80 per year) can store video up to 30 days, and adds in Familiar Face Detection. In addition, if you want 24/7 recording to the cloud, you’ll have to shell out $15 a month or $150 annually for the Nest Aware Plus plan.

We have completed a new round of testing and have a new indoor security camera top pick, the TP-Link Tapo C120. This roundup will be updated soon with full reviews.

Barrel distortionexamples

Unlike other types of distortion which are part of the inherent properties of the lens, keystone distortion is caused by improper alignment in a lens array. As light hits each lens and is transmitted onward, rays cross, resulting in parallax and a trapezoidal image. Keystone distortion can often be avoided by careful attention to alignment when creating lens arrays, and may also be corrected in post-processing.

Mustachedistortion

The E340 supports both Amazon Alexa and Google Home, but currently Google Home only supports voice control of the light and doesn’t allow manually tweaking it using the app.

The Eufy Floodlight Camera E340 combines a bright outdoor LED light with two surveillance cameras: one with a 2K telephoto lens and the other a 3K resolution wide-angle camera. The E40 can survey a far greater area than other models because both cameras can pan and tilt 360 degrees horizontally and 120 degrees vertically. Both cameras can track and follow motion well, capturing clear images day and night—both with and without color night vision. Video can be stored internally on a removable microSD card (up to 128 GB), to the HomeBase S380 hub (sold separately), or in the cloud (if you opt for a subscription; they start at $3 per month). Two integrated LED panels capable of blasting 2,000 lumens of brightness can be turned on and off or tweaked via the Eufy app or voice control.

Rachel Cericola is a writer covering smart home. In addition to testing hundreds of smart devices, she has also tested dozens of ice cream sandwiches.

The TP-Link Tapo Wire-Free Magnetic Security Camera is relatively inexpensive compared to our other picks yet captures clear 2K video and includes a long-life internal battery so you can install it anywhere within reach of your Wi-Fi signal. You have the option to store video for free, using local video storage via a microSD card, or using a paid cloud subscription which enables 30 days of storage for $3.50 per month (or $35 per year for one camera). With or without a subscription AI detection is enabled—not all cameras include that—so it can distinguish between various motion triggers including, people, vehicles, and pets. To limit the volume of nuisance recordings you can create Activity Zones that tell the camera what it should and shouldn’t record—for example, you might have one zone triggered by vehicles and animals, and another zone that records only people.

F-theta lenses (used in laser scanning systems) are usually designed to produce a certain amount of distortion (barrel distortion) so that the image height is proportional to the field angle of θ. The ideal image height of an f-theta lens can be calculated using Equation 4

A smart doorbell camera allows you to see who’s on the other side of your front door so you can screen visitors and package deliveries—even if you aren’t home.

What is barrel distortioncorrection

Some lenses that are engineered to exhibit very low levels of distortion may have both positive and negative distortion. This type of distortion is called moustache or wave distortion, and requires special attention to wavelength when calibrating software to remove distortion from the final image.

People who want the sense of security that comes with motion-activated lighting, along with the additional assurance of recorded or live video. The built-in LED also makes video images brighter.

At $3.50 per month per camera, the cloud service is competitively priced. However, the price continues to increase when you add cameras, $7 for two cameras, $10.50 for three, and $12 for up to 10.

Also, the Nest doorbell isn’t compatible with the old Nest app since newer Google products have switched to using Google Home. However, useful Nest app features like the ability to “favorite” the doorbell so you can view the live feed upon opening Google Home have made the transition easier.

Similar to all Eufy cameras, this model downgrades 2K footage to 1080p and 3K footage to 2K when it is uploaded to the cloud. Still, we always recommend cloud video storage for security reasons—if someone steals or damages your camera, you don’t lose your recordings—and in real-world use, we noticed a drop in image quality only when we deliberately compared videos side by side (and it’s still of good quality).

In some situations, distortion is engineered into a system. There are many reasons why a lens distortion effect may be desirable. In laser applications, f-theta lenses are chosen to introduce a certain amount of distortion into an optical system. In cameras, image creators use an effects library which includes radial distortion, barrel distortion, perspective distortion and pincushion distortion to introduce novelty effects into their images. Wide angle lenses and zoom lenses also create their own signature type of distortion.

This camera delivers high-resolution images and can distinguish between people, pets, and motion, a feature usually available on high-priced models.

People who want a permanently installed way to screen visitors at the door, whether they’re on the other side of the door or the other side of the world.

Pincushiondistortionlens

Alpha Industrial Park, Tu Thon Village, Ly Thuong Kiet Commune, Yen My District, Hung Yen Province Vietnam 17721 +84 221-730-8668 rfqvn@shanghai-optics.com

This cord-free camera offers excellent battery life, the option to store recordings locally or in the cloud, and the best array of customizations for the money.

Our extensive optical experience and state of the art metrology equipment allows us to test every lens which we manufacture at Shanghai Optics, and we can provide distortion curves for specific lenses upon request. Although distortion is primarily cosmetic, it remains an important quality of every lens and the level of distortion can greatly change the ease in which information is gleaned from a system or the CPU load required for post processing.

The Familiar Face Detection feature (a feature that “recognizes” and names frequent visitors) included with the Nest Aware subscription can be faulty. It needs a good look at your visitors to work properly–and even then it still gets some wrong, but you can correct it.

A good home security system should make it easy to find peace of mind. It can alert you to an open door or window, frighten away prowlers, and call for help.

Pincushiondistortion

Room 609, 6/F, Global Gateway Tower, No.63 Wing Hong Street, Cheung Sha Wan, Kowloon, Hong Kong +852-54993705 info@shanghai-optics.com

Wi-Fi security cameras let you keep tabs on packages outside your home, pets on the couch, and even prowlers raiding your refrigerator. We’ve done hundreds of hours of research and testing on outdoor, indoor, hardwired, cordless, and doorbell Wi-Fi cameras, searching for the best models to fit a variety of homes, budgets, and security needs. If you want to know what’s going on when you’re away, one of our camera recommendations will do the job.

Apple’s cloud service for security cameras has many great features, including the price—but we don’t recommend it for most people.

What is barrel distortionin glasses

Although the Eufy Solo IndoorCam C24 delivers vivid 2K images for live viewing or recording to a microSD card, it downgrades clips stored on NAS devices and in the cloud to 1080p resolution. In our tests we always found its images to be sharp regardless of the storage method, but if 2K resolution is important to you, opt to use a microSD card.

As with other aberrations, a lens with a larger field of view will generally exhibit a larger amount of distortion. A fisheye lens or ultra wide-angle lens produces strong visual distortion. Figure 3 shows the distortion in a fisheye lens with effective focal length of 3.0mm. Figure 4 shows a simulated image of a wide angle lens with -50% distortion.

People who want to keep tabs on what’s going on inside, whether they’re checking in on kids and pets or watching for unidentified houseguests.

I write about everything from smart lighting and home security to Wi-Fi cameras and smart bird feeders. I’ve also covered ice cream sandwiches, robot vacuums, and snoring.

Distortion in a simple lens is a third-order aberration which increases with the cube of the field height. Since distortion affects the image shape, its appearance is very important especially in visual systems. Generally distortion in the order of 2 to 3% is acceptable visually. Figure 2 shows images of a rectilinear object with zero distortion and -3% distortion.

As with other aberrations, F-theta distortion is determined by the optical design of the lens. Shanghai Optics Inc. has over 55 years of experience in design and manufacturing low distortion f-theta lenses. Fig.5 shows the F-Theta

Distortion correction can be done post production in a photo editor, since the amount of distortion a lens introduces can be mathematically quantified at any given point. Distortion varies with wavelength, and in situations where a narrow band of light is used it may be computed at the central wavelength.  Digital fine-tune programs are often used to provide lens correction and eliminate unwanted distortion from a final image.

This hardwired floodlight has two pan-and-tilt HD cameras, and it stores video internally for free or in the cloud with a subscription. Its bulb is light but dimmable.