When it comes to ring lights, size does matter. The tiny ones that clip on to your cell phone or those intended for personal makeup probably won’t do the job. As the ring becomes smaller the light effectively becomes a light point source, and point sources are good at producing hard light rather than the flattering soft light we want to make the subject look better. Basically, the larger the better. In a video studio, I would want a ring light with a diameter of at least 14” and preferably 20”. But that wouldn’t be suitable for a Zoom call at a home or office desk. In that situation the webcam or smartphone will typically be at arms length, and so will the ring light. At such a distance there is no need to go for a 14” to 20” ring light. At such close distances, an 8”-10” ring light should be fine.