Many cameras are found not to respect the industrial standard for C-mount (17.52 mm), which defines the flange-to-detector distance (flange focal length). Besides all the issues involved with mechanical inaccuracy, many manufacturers don’t take into the due account the thickness of the detector’s protection glass which, no matter how thin, is still part of the actual flange to detector distance.

32 InchesRing Light

These accessories make using a ring light easier, but they’re just extras. Prioritize the features above when choosing a ring light.

You should be able to bend the light and raise it up or down to get the most flattering light for whatever you’re shooting. People who wear glasses, for example, might need to raise the light and adjust it at a steeper angle to avoid glare and reflections.

More expensive doesn’t mean better quality. While researching this guide, we saw a Wescott 18-inch Ring Light that cost nearly $200 despite having only two color temperatures (cool and warm). Some ring lights cost twice as much as similar-size lights without adding more features or benefits.

It’s easy to get up and running with Zoom, but you may not know about some of its best, most useful videoconferencing features.

Melanie Pinola is a writer focused on home-office gear. To find the best paper shredder, she has shredded enough junk mail to fill several bathtubs.

Color temperature, measured in kelvins (K), greatly affects the aesthetics of your photo or video. The room you’re in, the clothes you’re wearing, and your skin tone can all look different depending on the light’s color and temperature.

LargeRing Light

In addition to a stand, most ring lights come with extras such as a carrying case for the light, a mount for your phone, and a Bluetooth remote to take a photo on your phone from a distance.

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For desktop use, a 12-inch model is best. If you plan on using a ring light propped up on your desk—not on a tall stand on the floor—look for a moderately sized model, like the Godox LR120 12-inch LED Ring Light. These have stands designed for desktop use and cost less than larger models.

Smaller, USB-powered lights are great for mobile use. Ring lights that are 12 inches or smaller can be powered via USB, whereas the larger ring lights use an AC/DC adapter because they need to draw more power. So if you want a ring light that you can use outdoors—tethered to a laptop or USB power bank, without an outlet nearby—a ring light that’s 12 inches or smaller is ideal.

“It’s really empowering,” said content creator and educator Gia Goodrich, “because you know that even if you’re showing up without makeup, you feel insecure, or you’re in your PJs, you can at least light yourself in a way that makes you feel good.”

After researching and testing more than a dozen ring lights, we’ve learned that it’s a fast-moving category with lots of brands that may be here today but gone tomorrow. Many of the best ring lights we’ve tested are either now discontinued or have recurring stock issues. This includes the Neewer 14-inch LED Ring Light (RL-14), Neewer 16-inch LED Ring Light (RL-16), Yesker 14-inch Ring Light, and Godox LR120 12-inch LED Ring Light.

Whether you work from home or you need to nail a job interview via Skype, these are Wirecutter’s tips for looking and sounding like a pro on video calls.

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).

We’ll be testing more ring lights soon with the goal of recommending specific picks. In the meantime, the current guide remains a reliable resource for finding great lighting options.

A ring light is a simple, cost-effective option that anyone can set up and use. It makes the most sense when you need just a bit more emphasis on yourself in a space without a lot of natural light and you don’t have the time or energy to invest in a pricier professional lighting setup.

where s (s’ ) is the object (image) position with respect to the lens, customarily designated by a negative (positive) value, and f is the focal length of the optical system (cf. Fig. 1). The distance from the object to the front lens is called working distance, while the distance from the rear lens to the sensor is called back focal distance. Henceforth, we will be presenting some useful concepts and formulas based on this simplified model, unless otherwise stated.

Different mechanical mounting systems are used to connect a lens to a camera, ensuring both good focus and image stability. The mount is defined by the mechanical depth of the mechanics (flange focal distance), along with its diameter and thread pitch (if present). It’s important that the lens flange focal distance and the camera mount flange distance are exactly the same, or focusing issues may arise. The presence of a threaded mechanism allows some adjustment to the back focal distance if needed. For example, in the Opto Engineering® PCHI series lenses, the back focal adjustment is needed to adjust the focus for a different field of view.

Without it, you can look grainy, out of focus, or even shadowy—like an anonymous witness in a true-crime show. A ring light is a simple tool whose diffuse glow can bring you out of the dark and make you look more professional.

A certain number of parameters must be considered when choosing optics, depending on the area that must be imaged (field of view), the thickness of the object or features of interest (depth of field), the lens to object distance (working distance), the intensity of light, the optics type (telecentric/entocentric/pericentric), etc.

This is why a spacer kit is supplied with Opto Engineering® telecentric lenses including instructions on how to tune the back focal length at the optimal value.

Some larger models have a built-in USB port for phone charging. A few lights we tested that are 14 inches or larger had a USB port for charging your phone while it’s attached to the ring light. That’s convenient for long shoots.

Melanie Pinola covers home office, remote work, and productivity as a senior staff writer at Wirecutter. She has contributed to print and online publications such as The New York Times, Consumer Reports, Lifehacker, and PCWorld, specializing in tech, work, and lifestyle/family topics. She’s thrilled when those topics intersect—and when she gets to write about them in her PJs.

The bigger the ring light, the better the light output and quality. We looked at 10-, 12-, 14-, 16-, and 18-inch models suited for sitting at a desk or standing.

VAT IT02011230204 Fiscal code and registration number at Mantova Business Register 02011230204 Nr. REA: MN-216669 - Share Capital: 205.258,00 € 沪ICP备12040578号-2

A common F-number value is F/8 since smaller apertures could give rise to diffraction limitations, while lenses with larger apertures are more affected by optical aberrations and distortion. A rough estimate of the field depth of telecentric and macro lenses (or fixed focal length lenses used in macro configuration) is given by the following formula:

24 inchRing Light

Many of the latest ring light models also have a Wi-Fi remote to power the light and adjust the color temperature or brightness.

The focal length and the focus plane coincide only when the object is placed at an infinite distance, indeed beams from a point on the object can be considered as parallel. When instead the distance from the object is ‘short’ (rule of thumb: <10x Focal length), we are in macro mode and the focus plane is placed further away from the optical system compared to the focal length.

Each camera mount is more commonly used with certain camera sensor formats. The most typical sensor formats are listed below. It is important to remember that these are not absolute values – i.e. two cameras listed with the same sensor format may differ substantially from one another in terms of aspect ratio (even if they have the same sensor diagonal). For example, the Sony Pregius IMX250 sensor is listed as 2/3” and has an active area of 8.45 mm x 7.07 mm. The CMOSIS CMV2000 sensor is also listed as 2/3” format but has an active area of 11.26 mm x 5.98 mm.

C-mount is the most common optics mount in the industrial market. It is defined by a flange focal distance of 17.526 mm, a diameter of 1” (25.4 mm) with 32 threads per inch.

Our tests showed that a Bluetooth speakerphone won’t necessarily produce better results than a smartphone. But we found a few models worth checking out.

Expect to pay between $50 and $100 for a good ring light that has all of the features we mention above. Paying any more than that is likely throwing money away.

Find the right temperature for your skin tone. Wirecutter’s Rago said that warm light generally works best for most skin tones, but if it’s too warm, a person could look orange. Bluish light can make a pale person look lifeless.

F-mount is a bayonet-style mount originally developed by Nikon for its 35 mm format cameras and is still found in most of its digital SLR cameras. It is commonly used with bigger sensors, e.g. full-frame or line-scan cameras. Lenses can be easily swapped out thanks to the bayonet mount, but no back focal adjustment is possible.

A professional video producer shows how you can tweak the lighting you have in your home office to elevate your video-call look.

CS-mount is a less popular and 5 mm shorter version of the C-mount, with a flange focal distance of 12.526 mm. A CS-mount camera presents various issues when used together with C-mount optics, especially if the latter is designed to work at a precise back focal distance.

The main features of most optical systems can be calculated with a few parameters, provided that some approximation is accepted. The paraxial approximation requires that only rays entering the optical system at small angles with respect to the optical axis are taken into account. The thin lens approximation requires the lens thickness to be considerably smaller than the radii of curvature of the lens surfaces: it is thus possible to ignore optical effects due to the real thickness of the lenses and to simplify ray-tracing calculations. Furthermore, assuming that both object and image space are in the same medium (e.g. air), we get the following fundamental equation:

Typical F-numbers are F/1.0, F/1.4, F/2, F/2.8, F/4, F/5.6, F/8, F/11, F/16, F/22, etc. Every increment in the F-number (smaller aperture) reduces incoming light by a factor of 2. The given definition of F-number applies to fixed focal length lenses where the object is located ‘at infinity’ (i.e. a distance much greater than its focal length). For macro and telecentric lenses where objects are at a closer distance, instead, the working F/# (wF/#)is used. This is defined as:

Having multiple brightness levels means you can adjust the lighting to any environment—whether it’s cloudy or sunny, morning or night, or you have few or many other light sources.

The F-number affects the optics depth of field (DoF), that is the range between the nearest and farthest location where an object is acceptably in focus. Depth of field is quite a misleading concept because physically there is one and only one plane in object space that is conjugate to the sensor plane. However, being mindful of diffraction, aberration and pixel size, we can define an “acceptable focusing distance” from the image conjugate plane, based on subjective criteria. For example, for a given lens, the acceptable focusing distance for a precision gauging application requiring a very sharp image is smaller than for a coarse visual inspection application.

We still recommend these models if you can find them in stock. But if you can’t track them down, here are some tips that will help you choose a suitable replacement among a sea of similar-looking lights.

Wirecutter’s Melanie Pinola has spent years testing and reviewing various gear—including home-office essentials such as webcams, USB microphones, and office chairs—for Wirecutter and other sites including Lifehacker, PCWorld, Popular Mechanics, and Laptop Magazine.

More flexibility is always better. Bonus points go to ring lights—such as the Yesker 14-inch—that include a flexible gooseneck mount for your phone; this is great for getting the angle of your phone just right too.

Look for lights that can adjust brightness in 1% increments. With some ring lights, you can adjust the brightness from 0 to 100% in 10% increments (10% brightness, 20% brightness, and so on), but we prefer models that let you fine-tune the brightness to the nth degree. Some ring light descriptions will specify this; it might be called “stepless adjustment.”

You can certainly find other lighting setups that produce better portrait or video lighting—such as this two-light kit Goodrich recommends, which includes lighting umbrellas, several light stands, and a number of photo bulbs. But they’re more expensive and more complicated to set up and break down.

Lighting plays an important role in the image quality of your videos and photos, second only to the quality of your camera. But you don’t have to invest in a complicated lighting rig to get better close-ups.

For anything else, a 14- or 16-inch ring light will do. These larger models should suffice if you want to keep the stand off of your desk or you plan on using the ring light while standing. The 14-inch ring lights we tested, including the Neewer 14-inch and Yesker 14-inch, were plenty bright in our testing. A 16-inch ring light, such as the Neewer 16-inch, would be brighter. But that extra luminance is really only useful if you’re going to position the light several feet away from you.

More steps between the coolest and warmest color temperature levels mean more flexibility in suiting your skin and environment.

It’s also worth considering the height range of the ring light’s stand. The greater the range, the more versatile it will be to accommodate all kinds of situations.

A CRI of 90 or higher is best. Ring lights with a CRI of 90 or above are considered excellent, whereas those with a CRI between 80 and 90 are thought of as good, according to Westinghouse Lighting.

The focal length is a typical characteristic of an optical system. It is a measure of how strongly the system converges or diverges rays of light. If collimated rays converge to a physical point, the lens is said to be positive (convex), whereas if rays diverge the focus point is virtual and the lens is said to be negative (concave). All optics used in machine vision applications are overall positive, i.e. they focus incoming light onto the sensor plane. CCTV lenses are commonly identified by their focal length, expressed in millimeters (12mm, 25mm, 35mm, etc.).

Mxx-mounts are different types of camera mounts defined by their diameter (e.g. M72, M42), thread pitch (e.g. 1 mm, 0.75 mm) and flange focal distance. They are a common alternative to the F-mount for larger sensors.

Macro and telecentric lenses are designed to work at a distance comparable to their focal length (finite conjugates), while fixed focal length lenses are designed to image objects located at a much greater distance than their focal length (infinite conjugates). It is thus convenient to classify the first group by their magnification, which makes it easier to choose the proper lens given the sensor and object size, and the latter by their focal length.

CRI is one measure of light quality; the higher the CRI (the closer to 100, the better), the more colors the light can render and the more precise the image is color-wise.

But going too big causes issues, too. On the flip side, the 18-inch models were overkill: They were so bright that they created washed-out images at all but the lowest brightness levels.

Every optical system is characterized by an aperture stop, that determines the amount of light that passes through it. For a given aperture diameter d and focal length f we can calculate the optics F-number:

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Since fixed focal length lenses also follow the previous equation, it is possible to calculate the required focal length given the magnification and working distance, or the required working distance given the sensor size, field of view and focal length, etc. (some examples are given at the end of this section). For macro and telecentric lenses instead, the working distance and magnification are typically fixed.

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where p is the sensor pixel size (in microns), M is the lens magnification and k is a dimensionless parameter that depends on the application (reasonable values are 0.008 for measurement applications and 0.015 for defect inspection). For example, taking p = 5.5 µm and k = 0.015, a lens with 0.25X mag and WF/# = 8 has an approximate DoF = 10.5 mm.

Improving the lighting when you are in front of the camera isn’t just about vanity: Having great lighting that helps you look your best breeds confidence.

A ring light is exactly what its name suggests: a doughnut-shaped light, typically made of rows of LEDs. The halo shape diffuses light over a wide area, reducing shadows and washing away blemishes for a more-flattering appearance. The space in the middle of the light is a great place to mount a camera or phone because you get an even distribution of light around the lens.

More color temperature settings is better. Most of the ring lights we considered had at least three color-temperature settings: cool, neutral, and warm. We preferred those that offered more color-temperature steps between the coolest and the warmest levels; this allows you to dial in the setting that looks best with your skin and environment.

You might not find the CRI rating in the product description, but that doesn’t mean the ring light has a low CRI. Contact the manufacturer and ask for the number. If they don’t get back to you—or, worse, they don’t have a website—move on to the next ring light you’re considering.

Wirecutter’s Rozette Rago and Michael Hession, our head of photography and video, helped me determine the most important features to look for in a ring light.

10-inch lights aren’t great for most uses. These smallest lights had stands that raised the light only an inch off the desk, creating spooky, unflattering under-chin lighting. You could prop one of these lights up on a stack of large books or a box, but we think it’s worth paying a little more for a larger, brighter light that has a taller stand.

The basic purpose of a lens of any kind is to collect the light scattered by an object and recreate an image of the object on a light-sensitive ‘sensor’ (usually CCD or CMOS based).

For common optical systems, in thin lens approximation, the focal length is the distance over which collimated rays coming from infinity converge to a point on the optical axis.

For optical systems used in machine vision, in which rays reflected from a faraway object are focused onto the sensor plane, the focal length can be also seen as a measure of how much area is imaged on the sensor (Field of View): the longer the focal length, the smaller the FoV and vice versa (this is not completely true for some particular optical systems, e.g. in astronomy and microscopy).

How far or close you put a ring light depends mostly on your comfort level and the size of the light. But I found that for video-call purposes, somewhere between 2 and 3 feet was most flattering.